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Menna T, Cassese G, Modugno F, Chersi A, Buono C, Ruffilli A. Characterization of a dodecapeptide containing a dominant epitope of Par j 1 and Par o 1, the major allergens of P. judaica and P. officinalis pollen. Allergy 2012. [DOI: 10.1111/j.1398-9995.1999.tb05151.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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2
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Severino A, Abbruzzese C, Manente L, Valderas AA, Mattarocci S, Federico A, Starace G, Chersi A, Mileo AM, Paggi MG. Human papillomavirus-16 E7 interacts with Siva-1 and modulates apoptosis in HaCaT human immortalized keratinocytes. J Cell Physiol 2007; 212:118-25. [PMID: 17348035 DOI: 10.1002/jcp.21011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The viral factor E7 plays a key role in the well-established association between "high-risk" Human Papillomavirus (HPV) infection and the development of epithelial malignant tumors, as uterine cervix and ano-genital cancer. To delve into the molecular mechanisms of HPV-mediated cell transformation, we searched for novel potential cellular targets of the HPV-16 E7 oncoprotein, by means of the yeast two-hybrid technique, identifying a protein-protein interaction between HPV-16 E7 and the pro-apoptotic cellular factor Siva-1. Using co-precipitation assays and the "PepSets" technique, we confirmed this physical interaction and mapped accurately, for both proteins, the amino acid residues involved. Additionally, we found that HPV-16 E7 competed in vitro with the binding of the Bcl-X(L) anti-apoptotic factor to Siva-1, an interaction that has a major inference in UV radiation-induced apoptosis. In HaCaT immortalized human keratinocytes, forced HPV-16 E7 expression by retroviral infection caused Siva-1 transcript up-regulation, detected by cDNA macroarray hybridization and real-time quantitative PCR, paralleled by an increased amount of protein. Confirming the anti-apoptotic role of HPV-16 E7 in the HaCaT cellular model, evaluated by nuclear morphology, we also found that Siva-1 expression produced a significant increase of the apoptotic rate in UV radiation-exposed HaCaT cells, and that this effect resulted explicitly counteracted by HPV-16 E7. Being apoptosis a key physiological process for the elimination of irreversibly injured cells, the anti-apoptotic role of HPV-16 E7, performed at least by its interference with Siva-1, can be considered an additional mechanism for the survival of damaged, potentially transforming, cell clones.
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Affiliation(s)
- Anna Severino
- Department for the Development of Therapeutic Programs, Regina Elena Cancer Institute, Rome, Italy
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3
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Bruno T, De Nicola F, Iezzi S, Lecis D, D'Angelo C, Di Padova M, Corbi N, Dimiziani L, Zannini L, Jekimovs C, Scarsella M, Porrello A, Chersi A, Crescenzi M, Leonetti C, Khanna KK, Soddu S, Floridi A, Passananti C, Delia D, Fanciulli M. Che-1 phosphorylation by ATM/ATR and Chk2 kinases activates p53 transcription and the G2/M checkpoint. Cancer Cell 2006; 10:473-86. [PMID: 17157788 DOI: 10.1016/j.ccr.2006.10.012] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2005] [Revised: 07/18/2006] [Accepted: 10/05/2006] [Indexed: 12/14/2022]
Abstract
Che-1 is a RNA polymerase II-binding protein involved in the transcription of E2F target genes and induction of cell proliferation. Here we show that Che-1 contributes to DNA damage response and that its depletion sensitizes cells to anticancer agents. The checkpoint kinases ATM/ATR and Chk2 interact with Che-1 and promote its phosphorylation and accumulation in response to DNA damage. These Che-1 modifications induce a specific recruitment of Che-1 on the TP53 and p21 promoters. Interestingly, it has a profound effect on the basal expression of p53, which is preserved following DNA damage. Notably, Che-1 contributes to the maintenance of the G2/M checkpoint induced by DNA damage. These findings identify a mechanism by which checkpoint kinases regulate responses to DNA damage.
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Affiliation(s)
- Tiziana Bruno
- Experimental Chemotherapy Laboratory, Department of Experimental Oncology, Regina Elena Cancer Institute, 00158 Rome, Italy
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4
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Chersi A, Ferracuti S, Falasca G, Butler RH, Fruci D. Assembly and selective “in synthesis” labeling of quenched fluorogenic protease substrates. Anal Biochem 2006; 357:194-9. [PMID: 16930525 DOI: 10.1016/j.ab.2006.07.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 07/17/2006] [Accepted: 07/19/2006] [Indexed: 11/26/2022]
Abstract
Because impaired cellular protease activities are linked to many diseases, such as cancer, inflammation, neurodegeneration, and infection, internally quenched fluorescent peptides have recently been developed as tools for analyzing the specificities of these enzymes. Here we report convenient and cost-effective approaches for the selective "in synthesis" assembly of such substrate peptides for protease assays. Fluorescein and Dabcyl groups were covalently and selectively attached during synthesis to epsilon-amino groups of internal lysines. Functionality was then tested by digestion with leucine aminopeptidase, chymotrypsin, and microsomal vesicles. All peptides proved to be appropriate substrates of the enzymes tested and of the endogenous peptidases in the microsomal vesicles. In summary, we describe an innovative and cheap method to develop completely functional quenched fluorescent peptides that are usable in specific detection of individual proteases, in particular aminopeptidases, in both in vitro and in vivo systems.
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Affiliation(s)
- Alberto Chersi
- Laboratory of Biochemistry, Regina Elena Institute CRS, 00158 Rome, Italy
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5
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D'Agnano I, Valentini A, Gatti G, Chersi A, Felsani A. Oligopeptides impairing the Myc-Max heterodimerization inhibit lung cancer cell proliferation by reducing Myc transcriptional activity. J Cell Physiol 2006; 210:72-80. [PMID: 16998799 DOI: 10.1002/jcp.20810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Deregulated CMYC gene causes cell transformation and is often correlated with tumor progression and a worse clinical outcome of cancer patients. The transcription factor Myc functions by heterodimerizing with its partner, Max. As a strategy to inhibit Myc activity, we have synthesized three small peptides corresponding to segments of the leucine zipper (LZ) region of Max. The purpose of these peptides is to occupy the site of recognition between Myc and Max located in the LZ and inhibit-specific heterodimerization between these proteins. We have used the synthesized oligopeptides in two lung cancer cell lines with different levels of Myc expression. Results demonstrate that: (i) the three peptides resulted equally effective in competing the interaction between Myc and Max in vitro; (ii) they were efficiently internalized into the cells and significantly inhibited cell growth in the cells showing the highest Myc expression; (iii) one specific peptide, only nine aminoacids long, efficiently impaired the transcriptional activity of Myc in vivo, showing a more stable interaction with this protein. Our results are relevant to the development of novel anti-tumoral therapeutic strategies, directed to Myc-overexpressing tumors.
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Affiliation(s)
- Igea D'Agnano
- CNR, Istituto di Tecnologie Biomediche, Segrate-Milano, Italy.
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6
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Chersi A, Falasca G, Malorni W. A biochemical approach for detecting interactions between peptides from the HIV gp120 glycoprotein and a CD4 sequence. Z NATURFORSCH C 2004; 59:734-8. [PMID: 15540608 DOI: 10.1515/znc-2004-9-1019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Peptides selected from the HIV viral protein gp120 bind to a synthetic peptide mimicking sequence 78-89 of the human lymphocyte CD4 molecule, linked to activated Sepharose. The binding of viral fragments to the CD4 peptide-Sepharose beads was ascertained either by aid of a ninhydrin reagent or by fluorescence microscopy. A suitable alignment of these HIV peptides with the CD4 fragment showed that multiple interactions might occur between hydrophobic or charged groups of the two molecules. Although this experiment does not demonstrate that these two amino acid stretches are involved in the primary binding of gp120 to CD4 receptors, the present data suggest that the two sequences might have some kind of interaction during subsequent steps of viral infection.
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Affiliation(s)
- Alberto Chersi
- Regina Elena Institute for Cancer Research, Lab of Biochemistry, Via delle Messi d'oro 156, 00158 Rome, Italy.
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Chersi A, Galati R, Accapezzato D, Francavilla V, Barnaba V, Butler RH, Tanigaki N. Responses of peptide-specific T cells to stimulation with polystyrene beads carrying HLA class I molecules loaded with single peptides. J Immunol Methods 2004; 291:79-91. [PMID: 15345307 DOI: 10.1016/j.jim.2004.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2004] [Revised: 05/04/2004] [Accepted: 05/05/2004] [Indexed: 10/26/2022]
Abstract
Cell-sized microbeads carrying single peptide-loaded HLA class I molecules were prepared for HLA-A2 and HLA-B7 by a simple procedure which transfers single peptide-loaded HLA class I molecules from cultured cells to polystyrene beads using anti-peptide antibodies directed to an intracellular segment of HLA-A alpha chains. The surface density of peptide-loaded HLA class I molecules on beads was comparable to that on the peptide-loaded cells. HLA-A2 beads loaded with an HCV peptide HCV1073 were tested for stimulation activity on an HCV1073-specific CD8+ T cell clone NS3-1. A substantial level of gamma-IFN production was induced. The stimulation was peptide-specific. The efficiency was dependent on the bead concentration and the surface HLA class I density on beads and enhanced significantly by co-coupling of anti-CD28 to peptide-loaded beads. The peptide-loading efficiency on HLA class I molecules and the transfer efficiency of HLA class I molecules to polystyrene beads were reasonably high for HLA-A2 and HLA-B7. Thus, polystyrene beads carrying these single peptide-loaded HLA class I molecules are potentially useful in further analysis of the co-stimulatory or inhibitory factors involved in CD8+ T cell responses and eventually in detection of cytotoxic T cells in PBLs.
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Affiliation(s)
- Alberto Chersi
- Department of Biochemistry, Regina Elena Institute for Cancer Research, Rome, Italy
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8
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Abstract
The ability of synthetic protein fragments to survive the degradative action of aminopeptidases and serum proteolytic enzymes can be remarkably enhanced by slight modifications at their N-terminal alpha-amino group. This can be achieved by addition of beta-alanine or amino acids of the D-configuration, amino acids which are seldom found in a living organism. These modifications do scarcely modify the chemical and physical properties of the peptides, and should be preferred, especially for in vivo tests, to drastic alterations of peptides as produced by dinitrophenylation or dansylation of the amino groups.
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Affiliation(s)
- Rossella Galati
- Istituto Regina Elena for Cancer Research, Laboratory D (Biochemistry), Via delle Messi d'oro 156, 00158 Rome, Italy
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di Somma C, Fiore L, Di Lonardo A, Ridolfi B, Garzillo C, Chersi A, Buono C, Menna T, Ruffilli A. Cross-reactivity between the major Parietaria allergen and rotavirus VP4 protein. Allergy 2003; 58:503-10. [PMID: 12757452 DOI: 10.1034/j.1398-9995.2003.00176.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND The present study investigates immunological cross-reactivity between Par o 1, the major pollen allergen of Parietaria, and the VP4 protein of rotavirus, a microorganism that is world-wide the main etiological agent of gastroenteritis in children. METHODS IgG and IgE cross-reactivity was assessed by direct binding and competitive inhibition assays (ELISA and DARIA), using recombinant VP4 from rhesus infectious rotavirus (RR), synthetic peptides and Par o 1-specific antibodies affinity purified from pooled and individual human sera. RESULTS Antibodies specifically binding Par o 1, affinity purified from the sera of 35 individuals with skin test positivity to Parietaria and from 14 pools, were extensively cross-reactive with RRVP4. Cross-reactive binding was specifically inhibited by synthetic peptides derived from the C-terminal sequences of the VP4 proteins from human and rhesus infectious rotavirus. CONCLUSIONS This study reports the first evidence of cross-reactivity between an allergen and a viral antigen.
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Affiliation(s)
- C di Somma
- Institute of Genetics and Biophysics Adriano Buzzati Traverso, CNR, Naples, Italy
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10
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Bruno T, De Angelis R, De Nicola F, Barbato C, Di Padova M, Corbi N, Libri V, Benassi B, Mattei E, Chersi A, Soddu S, Floridi A, Passananti C, Fanciulli M. Che-1 affects cell growth by interfering with the recruitment of HDAC1 by Rb. Cancer Cell 2002; 2:387-99. [PMID: 12450794 DOI: 10.1016/s1535-6108(02)00182-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
DNA tumor virus oncoproteins bind and inactivate Rb by interfering with the Rb/HDAC1 interaction. Che-1 is a recently identified human Rb binding protein that inhibits the Rb growth suppressing function. Here we show that Che-1 contacts the Rb pocket region and competes with HDAC1 for Rb binding site, removing HDAC1 from the Rb/E2F complex in vitro and from the E2F target promoters in vivo. Che-1 overexpression activates DNA synthesis in quiescent NIH-3T3 cells through HDAC1 displacement. Consistently, Che-1-specific RNA interference affects E2F activity and cell proliferation in human fibroblasts but not in the pocket protein-defective 293 cells. These findings indicate the existence of a pathway of Rb regulation supporting Che-1 as the cellular counterpart of DNA tumor virus oncoproteins.
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Affiliation(s)
- Tiziana Bruno
- Laboratory B, Via delle Messi d'Oro 156, 00158 Rome, Italy
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11
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Chersi A, Galati R, Ogino T, Butler RH, Tanigaki N. Anti-peptide antibodies that recognize conformational differences of HLA class I intracytoplasmic domains. Hum Immunol 2002; 63:731-41. [PMID: 12175727 DOI: 10.1016/s0198-8859(02)00428-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Rabbit antibodies were raised against both long and short peptides derived from exon 7 sequences of human leukocyte antigen (HLA) class I alpha chains; anti-A/B against a 13-mer shared by most HLA-A alpha and HLA-B alpha chains, anti-C against a 15-mer characteristic of HLA-C alpha chains, anti-ACT against a 6-mer specific to HLA-A alpha chains, and anti-CCT against a 5-mer specific to HLA-C alpha chains. Binding activity of the antibodies was determined with peptides by enzyme-linked immunoabsorbent assay (ELISA) and with HLA class I transfectants and the parental cells by FACS analysis. Anti-A/B and anti-C were to a greater or lesser extent crossreactive with the long and short peptides, whereas anti-ACT and anti-CCT were specific to the corresponding short peptides. No binding was seen for anti-ACT and anti-CCT with HLA class I transfectants, C1R-A2, C1R-B7, and 221-Cw1 and the parental cells, C1R (Cw4, E) and 721.221 (E, F). Anti-A/B and anti-C were substantially protein-reactive and the binding order was C1R-B7 > C1R-A2, 721.221 > C1R, 221-Cw1 for anti-A/B, and C1R-B7 > 721.221 > C1R, 221-Cw1, C1R-A2 for anti-C. Thus, anti-A/B and anti-C bound better to HLA-B and HLA-E rather than to HLA-A and HLA-C. Computer modeling of the three-dimensional structure of the intracytoplasmic domains demonstrated that this may be due to structural differences despite the sequence similarities.
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12
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Ristori G, Montesperelli C, Fiorillo M, Battistini L, Chersi A, Sorrentino R, Borsellino G, Perna A, Tramonti D, Cannoni S, Perrone M, Giubilei F, Riccio P, Salvetti M, Buttinelli C. T cell response to N-formylated peptides in humans. Eur J Immunol 2001. [DOI: 10.1002/1521-4141(200109)31:9<2762::aid-immu2762>3.0.co;2-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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13
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Ristori G, Montesperelli C, Fiorillo MT, Battistini L, Chersi A, Sorrentino R, Borsellino G, Perna A, Tramonti D, Cannoni S, Perrone MP, Giubilei F, Riccio P, Salvetti M, Buttinelli C. T cell response to N-formylated peptides in humans. Eur J Immunol 2001; 31:2762-70. [PMID: 11536175 DOI: 10.1002/1521-4141(200109)31:9<2762::aid-immu2762>3.0.co;2-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We present the first evidence of a T lymphocyte response to N-formylated peptides in humans. N-formylated peptide sequences from self (mitochondrial) and foreign (microbial) antigens were used to isolate antigen-specific T cell clones from healthy individuals, including a set of monozygotic twins. The observed response differed from that previously described in mouse (CD4(+) phenotype and MHC class II restriction in humans vs. CD8(+) phenotype and class I restriction in mice). These lymphocytes produce substantial amounts of IFN-gamma. They were isolated in only one of the monozygotic twins, which suggests that their expansion in the healthy immune repertoire is independent of the genetic background. Our result will help in assessing the relevance of N-formylated peptide-specific T cells in protection against infections within the human immune system.
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Affiliation(s)
- G Ristori
- Department of Neurosciences, Università La Sapienza, Rome, Italy
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Abstract
Allelic variations of in vitro HLA class I assembly have been investigated in both the absence and the presence of binding peptides by flow cytometry using human leukocyte antigen (HLA) class I alpha chains isolated by alkali treatment from cultured HLA homozygous B cells and polystyrene beads coated with anti-HLA class I alpha chain antibodies specific to the C-terminal segment (anti-HLA class I beads). The specificity of assembly was temperature dependent, while the stability of the assembled complex depended on the bound peptide. The efficiency of assembly was allele dependent and primarily ruled by the binding affinity of alpha chains with beta(2)m. Thus, an allele hierarchy could be defined for the binding of HLA-B alpha chain with beta(2)-microglobulin: B7, B18 > B35, B62 > B27, B51. Allele and temperature dependency was found in HLA class I reassembly on acid treated B cells. The HLA class I proteins, reassembled with specific single peptides, could be efficiently transferred to anti-HLA class I beads. These findings would be used to produce microspheres coupled at high surface density with oriented single-peptide loaded HLA class I molecules and also to improve the preparation efficiency of HLA class I tetramers by the use of site-specific biotinylation.
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Affiliation(s)
- A Chersi
- Regina Elena Institute for Cancer Research, Rome, Italy
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15
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Ortona E, Margutti P, Vaccari S, Riganò R, Profumo E, Buttari B, Chersi A, Teggi A, Siracusano A. Elongation factor 1 beta/delta of Echinococcus granulosus and allergic manifestations in human cystic echinococcosis. Clin Exp Immunol 2001; 125:110-6. [PMID: 11472433 PMCID: PMC1906106 DOI: 10.1046/j.1365-2249.2001.01569.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Allergic reactions, such as urticaria, itching and anaphylactic shock, often complicate the course of cystic echinococcosis (CE). To investigate the role of the IgE-immunoreactive recombinant Echinococcus granulosus elongation factor-1 beta/delta (EgEF-1 beta/delta) in the allergic disorders during CE we determined humoral and cell-mediated responses to this antigen in patients with CE grouped according to the clinical presence or absence of allergic reactions. Immunoblotting analysis showed that serum IgE-binding reactivity to EgEF-1 beta/delta differed significantly in patients with and without allergic reactions (38 of 42, 90% vs. 31 of 56, 56%; P < 10(-4)). EgEF-1 beta/delta induced a proliferative response in 14 of 19 (74%) patients' peripheral blood mononuclear cells (PBMC) irrespective of the allergic manifestations and skewed Th1/Th2 cytokine activation towards a preferentially Th2 polarization. Epitope mapping identified an immunodominant epitope of 18 residues with 78% identity and 89% similarity with an IgE-immunoreactive Strongyloides stercoralis antigen. Overall these findings suggest that EgEF-1 beta/delta is an allergenic molecule that may be a general marker of the intensity of CE immune response and that could lead to a deeper understanding of the specific antigen-induced mechanisms underlying allergic reactions in the human host.
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Affiliation(s)
- E Ortona
- Department of Immunology, Istituto Superiore di Sanità, Rome, Italy
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16
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Di Modugno F, Buglioni S, Mottolese M, Del Bello D, Cascioli S, Chersi A, Santoni A, Nisticò P. Polyclonal Antibodies Against gp185HER2 Peptides: Their Putative Role in the Identification of a Particular HER2 Status in Patients With Breast Cancer. J Immunother (1991) 2001; 24:221-231. [PMID: 11395637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
SUMMARY: The HER2 oncogene and its relative oncoprotein, gp185HER2, a transmembrane glycoprotein belonging to the epidermal growth factor receptor family, are overexpressed in a wide range of solid tumors including breast and ovarian cancer. In patients with breast cancer, both humoral and cell-mediated HER2 immune responses have been found as well as in some patients with gp185HER2 nonoverexpressing tumors. To establish whether peptide sequences identified as HLA-A2-restricted T-cell epitopes are expressed in breast tumor cell lines and tissues, we produced and characterized by different methodologic approaches polyclonal antibodies raised against four gp185HER2 peptides. Two of the antibodies recognized peptides eluted from the HLA-A2 groove of the mDAmB231 breast cancer cell line expressing a basal level of gp185HER2. Paraffin-embedded primary and metastatic breast tumors were specifically immunostained by all four reagents, thereby showing an overlapping reactivity. When this immunoreactivity was compared with that obtained using two different monoclonal antibodies, in 105 breast primary tumors and 36 corresponding lymph node metastases, we identified a subset of tumors that were negative with anti-gp185HER2 monoclonal antibodies and positive with the four antipeptide antibodies. Our novel observations provide in vivo evidence of the complexity involved in evaluating HER2 expression, and open a new path for understanding the biologic significance of HER2 status in breast tumors.
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Affiliation(s)
- Francesca Di Modugno
- Laboratory of Pathophysiology, CRS Regina Elena Cancer Institute; Laboratory of Pathology, Regina Elena Cancer Institute; Laboratory of Biochemistry, CRS Regina Elena Cancer Institute; and Department of Experimental Medicine and Pathology, University of Rome "La Sapienza", Rome, Italy
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17
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Di Modugno F, Buglioni S, Mottolese M, Bello DD, Cascioli S, Chersi A, Santoni A, Nisticò P. Polyclonal antibodies against gp185HER2 peptides: their putative role in the identification of a particular HER2 status in patients with breast cancer. J Immunother 2001; 24:221-31. [PMID: 11394499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
The HER2 oncogene and its relative oncoprotein, gp185HER2, a transmembrane glycoprotein belonging to the epidermal growth factor receptor family, are overexpressed in a wide range of solid tumors including breast and ovarian cancer. In patients with breast cancer, both humoral and cell-mediated HER2 immune responses have been found as well as in some patients with gp185HER2 nonoverexpressing tumors. To establish whether peptide sequences identified as HLA-A2-restricted T-cell epitopes are expressed in breast tumor cell lines and tissues, we produced and characterized by different methodologic approaches polyclonal antibodies raised against four gp185HER2 peptides. Two of the antibodies recognized peptides eluted from the HLA-A2 groove of the mDAmB231 breast cancer cell line expressing a basal level of gp185HER2. Paraffin-embedded primary and metastatic breast tumors were specifically immunostained by all four reagents, thereby showing an overlapping reactivity. When this immunoreactivity was compared with that obtained using two different monoclonal antibodies, in 105 breast primary tumors and 36 corresponding lymph node metastases, we identified a subset of tumors that were negative with anti-gp185HER2 monoclonal antibodies and positive with the four antipeptide antibodies. Our novel observations provide in vivo evidence of the complexity involved in evaluating HER2 expression, and open a new path for understanding the biologic significance of HER2 status in breast tumors.
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Affiliation(s)
- F Di Modugno
- Laboratory of Pathophysiology, CRS Regina Elena Cancer Institute, Rome, Italy
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18
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Poloni F, Puddu P, Moretti F, Flego M, Romagnoli G, Tombesi M, Capone I, Chersi A, Felici F, Cianfriglia M. Identification of a LFA-1 region involved in the HIV-1-induced syncytia formation through phage-display technology. Eur J Immunol 2001. [PMID: 11169438 DOI: 10.1002/1521-4141(200101)31:1<57::aid-immu57>3.0.co;2-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have identified a peptide region on CD18 molecule (the beta subunit of the LFA-1 molecule) involved in syncytia formation of HIV-1-infected lymphocytes. Several phage clones mimicking an epitope of the CD18 cell-surface determinant were isolated from two 9-mer random peptide phage-displayed libraries via their binding to the CD18-specific monoclonal antibody (mAb) MHM23, which in in vitro assay inhibits syncytia formation in HIV-1-infected cells. The peptide sequences displayed on phages that blocked immunolabeling of this mAb on LFA-1-expressing cells were used to identify the epitope recognized by mAb MHM23 by sequence comparison. On the basis of this analysis, two peptides which inhibited syncytia formation in HIV-1-infected cells in vitro were synthesized, thus confirming that they mimic a CD18 domain that is involved in this phenomenon. The results here presented highlight the potential of phage-display technology for the study of biological processes at the basis of virus infection, but also suggest new approaches for the therapy of AIDS.
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Affiliation(s)
- F Poloni
- Laboratory of Immunology, Istituto Superiore di Sanità, Rome, Italy
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Chersi A, Pugliese O, Federico A, Viora M. Short synthetic peptides derived from viral proteins compete with HIV gp120 for the binding to CD4 receptors. Viral Immunol 2001; 13:547-54. [PMID: 11192301 DOI: 10.1089/vim.2000.13.547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In the complex mechanism of adhesion, internalization, and infection of cells by human immunodeficiency virus (HIV) viral particles, a determinant role is played by the viral envelope glycoprotein gp120, which binds to CD4 receptors of T cells and monocytes. We tested the ability of a panel of 7- to 12-residue synthetic peptides, selected from the region 414-434 of the HIV-1 gp120, to inhibit the binding of the viral protein to CD4 receptors of cultured human lymphoid cells. The assay was based on the observation that the binding of gp120 to the receptors interferes with the binding of a specific anti-CD4 monoclonal antibody, as a result of the masking of the antibody epitope; thus, we tested whether preincubation of cells with the peptides before gp120 addition might restore the recognition of the CD4 molecule by the antibody. High expression of CD4 receptors was thus assumed as indication that the binding of the viral protein had been inhibited. Maximum activity was displayed by a 9-residue peptide located near the amino terminal end of the 414-434 fragment. In addition, several fragments deduced from other viral proteins, possessing partial amino acid sequence homology with the HIV gp120 fragment, exhibited a similar type of interaction with the CD4 receptor. All active peptides contain the Cys residue (position 423 of gp120). This residue is essential, although not sufficient, for inhibiting gp120 binding, as few other amino acid residues within the fragment play a complementary role in increasing or decreasing the inhibitory ability.
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Affiliation(s)
- A Chersi
- Istituto Regina Elena for Cancer Research, Lab of Biochemistry, Rome, Italy.
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20
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Poloni F, Puddu P, Moretti F, Flego M, Romagnoli G, Tombesi M, Capone I, Chersi A, Felici F, Cianfriglia M. Identification of a LFA-1 region involved in the HIV-1-induced syncytia formation through phage-display technology. Eur J Immunol 2001; 31:57-63. [PMID: 11169438 DOI: 10.1002/1521-4141(200101)31:1<57::aid-immu57>3.0.co;2-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We have identified a peptide region on CD18 molecule (the beta subunit of the LFA-1 molecule) involved in syncytia formation of HIV-1-infected lymphocytes. Several phage clones mimicking an epitope of the CD18 cell-surface determinant were isolated from two 9-mer random peptide phage-displayed libraries via their binding to the CD18-specific monoclonal antibody (mAb) MHM23, which in in vitro assay inhibits syncytia formation in HIV-1-infected cells. The peptide sequences displayed on phages that blocked immunolabeling of this mAb on LFA-1-expressing cells were used to identify the epitope recognized by mAb MHM23 by sequence comparison. On the basis of this analysis, two peptides which inhibited syncytia formation in HIV-1-infected cells in vitro were synthesized, thus confirming that they mimic a CD18 domain that is involved in this phenomenon. The results here presented highlight the potential of phage-display technology for the study of biological processes at the basis of virus infection, but also suggest new approaches for the therapy of AIDS.
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Affiliation(s)
- F Poloni
- Laboratory of Immunology, Istituto Superiore di Sanità, Rome, Italy
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21
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Chersi A, Rosano L, Tanigaki N. Polystyrene beads coated with antibodies directed to HLA class I intracytoplasmic domain: the use in quantitative measurement of peptide-HLA class I binding by flow cytometry. Hum Immunol 2000; 61:1298-306. [PMID: 11163086 DOI: 10.1016/s0198-8859(00)00187-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Protein-reactive, conformation-independent anti-peptide antibodies were raised in rabbits against a C-terminal sequence SDSAQGSDVSLA, common to most HLA-A and -B locus products. Antibodies were coupled to 4.5-microm polystyrene beads through the Fc portion by the use of protein A. The antibody-coupled beads showed a high capacity to bind HLA-A and -B proteins as well as their alpha chains by the intracytoplasmic domain, keeping the extracellular domains solvent exposed. The density of HLA class I proteins bound on the beads was approximately the same as that on cultured B cells. The antibody beads made it possible to quantitate peptide-HLA class I binding, i.e., in vitro HLA class I assembly by flow cytometry. The assembly rate determined by the provisionally called flow cytometric HLA class I assay was 15%-19% for the reassembly of dissociated HLA class I proteins with the released selfpeptides. With single synthetic peptides, the highest rate so far obtained was 6.5%. The assay specificity and reproducibility were satisfactory.
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Affiliation(s)
- A Chersi
- Istituto Regina Elena for Cancer Research, Rome, Italy.
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22
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Ristori G, Montesperelli C, Perna A, Cannoni S, Battistini L, Borsellino G, Riccio P, Pesole G, Chersi A, Pozzilli C, Buttinelli C, Salvetti M. Global immune disregulation in multiple sclerosis: from the adaptive response to the innate immunity. J Neuroimmunol 2000; 107:216-9. [PMID: 10854659 DOI: 10.1016/s0165-5728(00)00219-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Increasing evidences show a global immune disregulation in multiple sclerosis (MS). The possible involvement of myelin and non-myelin (auto-)antigens in the autoaggressive process as well as the disregulation of both adaptive and innate immunity challenge the concept of specific immunotherapy. T cells at the boundary between innate and adaptive immunity, whose immunoregulatory role is becoming increasingly clear, have recently been shown to bear relevance for MS pathogenesis. Global immune interventions (and type I interferons may be considered as such) aimed at interfering with both innate and acquired immune responses seem to be a most promising therapeutic option in MS.
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Affiliation(s)
- G Ristori
- First Chair of Neurology, Dept. Neurosciences, Università "La Sapienza", Rome, Italy
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Abstract
A new method is described for the selective 'in synthesis' labeling of peptides by rhodamine or biotin at a single, predetermined epsilon-amino group of a lysine residue. The alpha-amino group and other lysyl residues of the peptide remain unmodified. Peptides are assembled by the Fmoc approach, which requires mild operative conditions for the final deprotection and cleavage, and ensures little damage of the reporter group. The labeling technique involves the previous preparation of a suitable Lysine derivative, easily obtained from commercially-available protected amino acids. This new derivative, where the reporter group (biotin, or rhodamine) acts now as permanent protection of lysyl side chain functions, is then inserted into the synthesis program as a conventional protected amino acid, and linked to the preceding residue by aid of carbodiimide. A simpler, alternative method is also described for the selective 'in synthesis' labeling of peptides with N-terminal lysyl residues. Several applications of labeled peptides are reported.
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Affiliation(s)
- A Chersi
- Regina Elena Institute for Cancer Research, CRS, Laboratory of Biochemistry, Via delle Messi d'oro 156, 00158, Rome, Italy
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24
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Giacomini E, Chersi A, Giordani L, Luzzati AL. Possible role of the plasminogen receptor as a site of interaction of the human immunodeficiency virus p24 immunosuppressive heptapeptide Ch7 with the host immune system. Scand J Immunol 2000; 51:164-7. [PMID: 10722370 DOI: 10.1046/j.1365-3083.2000.00672.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previous work from our laboratory demonstrated that a synthetic heptapeptide (Ch7: RGSDIAG), corresponding to a conserved sequence of human immunodeficiency virus (HIV) core protein p24 (amino acids 232- 238), was able to specifically abrogate antigen-induced responses in cultures of normal human peripheral blood mononuclear cells (PBMC), probably acting at the level of monocytes. The Ch7 peptide displays sequence homology to human plasminogen. In the present report we show that a compound (6-aminoexanoic acid), known to prevent plasminogen binding to monocyte-like cells, greatly reduced the immunosuppressive capacity of Ch7. We suggest that the plasminogen receptor may represent a target structure on human monocytes for the immunosuppressive p24 sequence.
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Affiliation(s)
- E Giacomini
- Department of Immunology, Istituto Superiore di Sanità, Rome, Italy
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Chersi A, di Modugno F, Rosano L. Flexibility of amino acid residues at position four of nonapeptides enhances their binding to human leucocyte antigen (HLA) molecules. Z NATURFORSCH C 2000; 55:109-14. [PMID: 10739109 DOI: 10.1515/znc-2000-1-220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The binding affinity of synthetic nonapeptides to human leucocyte antigens (HLA) molecules of the A0201 allotype, the most common in Caucasian, is enhanced or reduced by suitable amino acid substitutions at position 4, as a result of increased or decreased chain flexibility. A higher flexibility of the bond at this position correlates with an easier accommodation of the fragment into the HLA groove, while rigidity of the peptide chain appears to interfere. These data are based on two lines of evidence: a) most natural high affinity ligands for HLA-A0201 possess, at position 4, flexible residues b) substitutions of such residues by rigid amino acids results in a decrease of binding affinity.
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Affiliation(s)
- A Chersi
- Istituto Regina Elena for Cancer Research, Laboratory of Biochemistry, CRS, Roma, Italy.
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26
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Menna T, Cassese G, Di Modugno F, Chersi A, Buono C, Ruffilli A. Characterization of a dodecapeptide containing a dominant epitope of Par j 1 and Par o 1, the major allergens of P. judaica and P. officinalis pollen. Allergy 1999; 54:1048-57. [PMID: 10536883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
The pollen of Parietaria, a weed of the Urticaceae family, is a major cause of respiratory allergy in Europe, where the most common species are P. judaica and P. officinalis. Previously, we reported that a beta-galactosidase fusion protein (6a-BG) expressing a 26-bp cDNA fragment (6a cDNA) contained a dominant IgE-binding epitope (6a epitope) of the major allergens Par o 1 and Par j 1. The present study aimed to define the amino-acid sequence containing the 6a epitope. We analyzed the reactivity of anti-Par o 1 antibodies affinity purified from allergic patient sera with: 1) a panel of synthetic peptides deduced from the 6a nucleotide sequence using different reading frames 2) glutathione S-transferase (GST) fusion proteins containing selected peptides. The peptide NSARARADSCRI (p102) specifically bound anti-Par o 1 antibodies affinity purified from allergic patient sera or from rabbit anti-Par o 1 antiserum (ELISA). The related peptide NSARAGTSSCRI (p101) reacted to human but not to rabbit, anti-Par o 1 antibodies. GST fusion proteins containing p101 (GST 3.5) or p102 (GST 3.2) extensively inhibited the binding between Par o 1 and IgE or IgG antibodies from an allergic patient serum pool according to a dose-response curve. Percent inhibition of IgE antibodies binding obtained by absorbing a solution (50 microl) of affinity-purified antibodies with 5 microg of GST 3.2 or with 1.2 mg of GST 3.5 was 69% and 66%, respectively. In conclusion, the results of the present study indicate that the amino-acid sequences NSARARADSCRI (p102) and NSARAGTSSCRI (p101) contain the dominant epitope of Par o 1 and Par j 1 for human IgE and IgG antibodies indicated as 6a epitope. Moreover, the study shows that the epitope is conserved in recombinant molecules containing these peptides, irrespective of the fused polypeptide (beta-galactosidase or GST). The knowledge of the amino-acid sequence of this dominant epitope is important in therapeutic approaches to the development of allergen-derived haptens.
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Affiliation(s)
- T Menna
- International Institute of Genetics and Biophysics, CNR, Naples, Italy
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27
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Romagnoli G, Poloni F, Flego M, Moretti F, Di Modugno F, Chersi A, Falasca G, Signoretti C, Castagna M, Cianfriglia M. Epitope mapping of the monoclonal antibody MM12.10 to external MDR1 P-glycoprotein domain by synthetic peptide scanning and phage display technologies. Biol Chem 1999; 380:553-9. [PMID: 10384961 DOI: 10.1515/bc.1999.070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Epitope mapping of MDR1-P-glycoprotein using specific monoclonal antibodies (mAbs) may help in delineating P-glycoprotein topology and hence in elucidating the relationship between its structural organization and drug-efflux pump function. In this work, by using synthetic peptide scanning and phage display technologies, the binding sites of the mAb MM12.10, a novel antibody to intact human multidrug resistant (MDR) cells, were studied. The results we obtained confirm that two regions localized on the predicted fourth and sixth loops are indeed external and that MDR1 peptides covering the inner domain of the current 12 transmembrane segment (TMs) model of P-glycoprotein could form part of the MM12.10 epitope.
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Affiliation(s)
- G Romagnoli
- Laboratorio di Immunologia, Istituto Superiore di Sanità, Roma, Italy
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28
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Giacomini E, Giordani L, di Modugno F, Chersi A, Luzzati AL. Increased PGE2 production mediates the in vitro inhibitory effect of the human immunodeficiency virus P24 immunosuppressive heptapeptide Ch7. Scand J Immunol 1998; 48:248-53. [PMID: 9743208 DOI: 10.1046/j.1365-3083.1998.00389.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previous work from our laboratory demonstrated that a synthetic heptapeptide (Ch7), corresponding to a conserved sequence of human immunodeficiency virus (HIV) core protein p24 (amino acids 232-238), was able to specifically abrogate antigen-induced responses in cultures of normal human peripheral blood lymphocytes (PBL). Addition of recombinant human interferon-gamma (IFN-gamma) to Ch7-suppressed cultures restored the capacity to mount an antigen-specific antibody response, suggesting that a cytokine imbalance may be at the basis of the Ch7 immunosuppressive activity. In the present paper we show that the Ch7-dependent in vitro immunosuppression was accompanied by a significant up-regulation of prostaglandin E2 (PGE2) production and induction of interleukin-10 (IL-10)-secreting cells. In the presence of the PGE2 inhibitor indomethacin, IL-10 up-regulation was prevented and the induction of a specific antibody response was partially restored. PGE2 is indeed an important regulator of immune responses with the ability to differentially affect cytokine production. Thus, our results demonstrate that the Ch7 immunosuppressive epitope may primarily act by up-regulating PGE2 production and, through this mediator, by causing a cytokine dysregulation, finally responsible for immune response suppression.
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Affiliation(s)
- E Giacomini
- Department of Immunology, Istituto Superiore di Sanità, Rome, Italy
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29
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Di Modugno F, Castelli M, Chersi A. Isolation, characterization and comparison of antipeptide and antiprotein rabbit antibodies to the pi-isoform of glutathione S-transferase. Z NATURFORSCH C 1998; 53:902-10. [PMID: 9825545 DOI: 10.1515/znc-1998-9-1020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The main linear epitopes of pi-glutathione transferase (pi-GST, EC 2.5.1.18), an enzyme related to cancer progression in a restricted number of tumours, were identified by testing in ELISA the reactivities of polyclonal anti-pi-GST rabbit sera against a panel of 51 overlapping decapeptides, covering the whole 216-residue sequence of the protein. Several major reactivity peaks were detected, each covering two or three adjacent peptides. The most active fragments were then reconstructed by conventional solid-phase synthesis, linked to Sepharose, and used as affinity ligands for isolating specific anti-pi-GST antibody subsets. A second group of antisera was then prepared in rabbits by using as immunogens some of the above described synthetic fragments, linked to a carrier protein, and antipeptide antibodies purified by affinity chromatography. An ELISA test was then performed, using as antigens a panel of peptides and different isoforms of GST, in order to establish whether antibodies isolated from total anti-pi-GST sera would display higher reactivity and specificity, as compared to traditional antipeptide antibodies. Binding data clearly confirm that the formers might be indeed better reagents for the detection and possibly quantitation of pi-GST.
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Affiliation(s)
- F Di Modugno
- Laboratory of Biochemistry, Regina Elena Institute for Cancer Research, Roma, Italy
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30
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Di Modugno F, Mammi C, Rosanò L, Rubiu O, Nisticò P, Chersi A. MHC-peptide binding: dimers of cysteine-containing nonapeptides bind with high affinity to HLA-A2.1 class I molecules. J Immunother 1997; 20:431-6. [PMID: 9409448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Small peptides, 8-10 amino acids long, derived from degradation of cytoplasmic proteins by a proteasome-proteinase complex, are usually presented and recognized by CD8+ cytolytic T lymphocytes (CTLs) associated with major histocompatibility complex (MHC) class I molecules. Recently synthetic peptides were used for the in vitro induction of tumor-specific CTLs, offering another strategy in the study of the immune-response repertoire and providing a new tool in cancer vaccination and immunotherapy. Peptides derived from otherwise normal proteins, overexpressed in many tumors as products of the protooncogene, may represent a target for an immune response. This is the case of HER-2/neu gene (also known as ErbB-2), encoding a cysteine-rich glycoprotein transmembrane receptor with tyrosine kinase activity (gp185neu). Recent data, demonstrating that HLA-A2.1-related peptides are able to stimulate in vitro CD8+ lymphocytes, Prompted us to study the binding to HLA-A2.1 molecules of several gp185 synthetic peptides containing a cystein residue and to define the relevance of this amino acid residue in the reduced or oxidated form of the sulfhydryl group. We found that monomers and their homodimers, linked by a disulfide bridge, bind to HLA-A2.1 molecules with overlapping affinity. These results suggest that additional amino acids of the nonapeptide do not prevent the binding and the HLA refolding through chemical or sterical interactions. This might be of particular relevance for the in vivo processing of cysteine-rich proteins. Because ErbB-2 molecules, as tumor-differentiation antigens in melanoma, are cysteine-rich molecules, it may be relevant to evaluate the possible role of the cystine residues interacting with the T-cell receptor. The recognition of these heterodimers by CD8+ lymphocytes will require functional in vivo studies.
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Affiliation(s)
- F Di Modugno
- Laboratory of Biochemistry, Istituto Regina Elena for Cancer Research, Rome, Italy
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31
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Ristori G, Montesperelli C, Fiori P, Buttinelli C, Bomprezzi R, Kovacs D, Greco G, Chersi A, Riccio P, Mattei C, Salvetti M. 5-31-13 T cell response to mitochondrial antigens in patients with multiple sclerosis (MS). J Neurol Sci 1997. [DOI: 10.1016/s0022-510x(97)86474-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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32
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Abstract
A new method is described for producing fluorescently-tagged peptides containing specific internal derivatives of lysyl residues. The technique employs the base-labile Boc-Lys(Fmoc)-COOH derivative with base-catalyzed removal of the Fmoc protecting group during peptide synthesis and subsequent fluorescent derivatization of the deprotected epsilon-amino group of lysine. By this technique, other lysine residues and the alpha-amino group of the fragment remain unmodified, which could have some value in studies where it might be required to tag a single individual lysine residue within the peptide, but not the amino terminus. In spite of the fact that poly-substituted peptides are badly soluble and might seldom find a practical application, this technique also allows the introduction of different fluorochromes at different lysyl residues within the peptide, thus obtaining double fluorescence. The method, fast and easy, requires a limited number of manual operations during the automatic synthesis of peptides. Although peptide synthesizers provided with an oscillating glass reactor are more suitable for the manual interventions described, this technique might be also adapted to the newer instruments utilizing continuous-flow columns.
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Affiliation(s)
- A Chersi
- Laboratory of Biochemistry, Regina Elena Institute for Cancer Research, Rome, Italy
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33
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Chersi A, Di Modugno F, Rosano L. Aims and limitations in the use of antipeptide antibodies in molecular biology. Biol Chem 1997; 378:635-40. [PMID: 9278142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Antibodies to peptides obtained by synthesis and, to a much lesser extent, prepared by enzymatic digestion of proteins, have been widely used in the last ten years in a variety of immunochemical and biological investigations. There are however several limitations in the correct utilization of such reagents. In fact, in spite of their 'predetermined specificity', antipeptide antibodies often fail to discriminate related molecules, and their reactivity with native proteins may be scarce or even absent, even if the peptide has been selected from surface regions of the protein. Our critical point of view, concerning two main aspects of antipeptide antibody features, i.e. specificity and reactivity, will be presented here, as confronted with information from the available literature. We have selected a restricted number of references among hundreds of publications dealing with antipeptide antibodies: for sure we neglected outstanding papers on the subject, and we apologize in advance.
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Affiliation(s)
- A Chersi
- Istituto Regina Elena for Cancer Research, CRS, Laboratory of Biochemistry, Rome, Italy
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34
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Rosanó L, Di Modugno F, Romagnoli G, Chersi A. Definition of essential amino acid residues in the recognition of a peptide by a mouse monoclonal antibody. Z NATURFORSCH C 1997; 52:274-8. [PMID: 9167279 DOI: 10.1515/znc-1997-3-423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A mouse monoclonal antibody reacting in ELISA with a synthetic peptide representing a linear amino acid stretch of the protein antigen was tested on all overlapping 5-mer to 9-mer fragments of the peptide, as prepared by multi-pin synthesis. Analysis of the binding data suggests that several residues in the peptide might be relatively unrelevant for recognition, while few others seem to play a critical role as key residues. On the basis of such observations, we attempted to reconstruct an alternative essential epitope by introducing multiple amino acid substitutions in the 9-mer peptide exhibiting the best binding activity, and then tested its ability to be recognized by the monoclonal antibody.
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Affiliation(s)
- L Rosanó
- Istituto Regina Elena for Cancer Research, Laboratory of Biochemistry, Roma, Italy
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35
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Luzzati AL, Boirivant M, Giacomini E, Giordani L, Di Modugno F, Chersi A. Interferon-gamma (IFN-gamma) can counteract the in vitro inhibitory effect of an HIV p24 immunosuppressive heptapeptide. Clin Exp Immunol 1996; 105:403-8. [PMID: 8809126 PMCID: PMC2200524 DOI: 10.1046/j.1365-2249.1996.d01-778.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Previous work from our laboratory demonstrated that a synthetic heptapeptide (Ch7), corresponding to a conserved sequence of HIV core protein p24 (aa 232-238), was able to specifically abrogate antigen-induced responses in cultures of normal human peripheral blood lymphocytes (PBL). In the present study we show that Ch7 did not inhibit the induction of IFN-gamma-secreting cells nor the accumulation of IFN-gamma mRNA in antigen-stimulated cultures. However, delayed addition of recombinant human IFN-gamma to Ch7-suppressed cultures was able to restore fully the capacity to mount an antigen-specific antibody response. Thus, although the Ch7 immunosuppressive effect may not be directly related to a decreased production of IFN-gamma, an increased level of this cytokine is certainly able to counteract the negative effect of the peptide.
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Affiliation(s)
- A L Luzzati
- Department of Immunology, Istituto Superiore di Sanità, Rome, Italy
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36
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Chersi A, di Modugno F, Falasca G. Specificities of rabbit antisera to multiple antigen (MAP) peptides. Z NATURFORSCH C 1995; 50:735-8. [PMID: 8579691 DOI: 10.1515/znc-1995-9-1023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Two multiple antigen peptides consisting of 6 and 7 aminoa cid residues, respectively, plus a 12-residue fragment, used as a control, all linked to a polylysine core, were used as immunogens in rabbits in order to obtain an immune response. Rabbit antisera against such polymers were then tested in ELISA against a panel of antigens in order to analyze the specificities of the resulting antibodies. The responses were different for all three immunogens, being partially or totally directed, for two of the three compounds, including the 12-residue control MAP peptide, against the polylysyl core, which is considered as non immunogenic. The third MAP polymer was practically unable to elicit an immune response.
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Affiliation(s)
- A Chersi
- Regina Elena Institute for Cancer Research, CRS, Laboratory of Biochemistry, Roma, Italy
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37
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Cianfriglia M, Romagnoli G, Tombesi M, Poloni F, Falasca G, Di Modugno F, Castagna M, Chersi A. P-glycoprotein epitope mapping. II. The murine monoclonal antibody MM6.15 to human multidrug-resistant cells binds with three distinct loops in the MDR1-P-glycoprotein extracellular domain. Int J Cancer 1995; 61:142-7. [PMID: 7705928 DOI: 10.1002/ijc.2910610124] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A new murine monoclonal antibody (MAb), MM6.15, to human MDR1 P-glycoprotein was found to be reactive in ELISA with synthetic peptides selected from the predicted sequences of the first, fourth and sixth extracellular loop of MDR1-P-glycoprotein. In order to precisely define the MM6.15-binding site, a peptide library of overlapping 5- to 9-mer residues covering the entire sixth extracellular loop of both human and rodent class-1 P-glycoproteins was synthesized on polyethylene pins and tested for MAb binding. The results of this ELISA demonstrated that the MAb MM6.15 reacts only with human synthetic peptides and that the critical component of the MAb recognition is made up of the amino-acid sequence LVAHKL (residues 963-968 of the MDR1-P-glycoprotein) with histidine (H), lysine (K) and possibly leucine (L), key residues of this immunogenic domain.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/analysis
- ATP Binding Cassette Transporter, Subfamily B, Member 1/immunology
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/metabolism
- Antibody Specificity
- Binding Sites
- Cricetinae
- Drug Resistance, Multiple/genetics
- Drug Resistance, Multiple/physiology
- Epitope Mapping
- Extracellular Space/metabolism
- Histidine/metabolism
- Humans
- Leucine/metabolism
- Lysine/metabolism
- Mice
- Molecular Sequence Data
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Affiliation(s)
- M Cianfriglia
- Laboratorio di Immunologia, Istituto Superiore di Sanità, Rome, Italy
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38
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Luzzati AL, Giacomini E, Giordani L, Viora M, Chersi A, Camponeschi B, Pugliese O. An HIV p24 heptapeptide down-regulates antigen-specific responses in vitro interfering at the level of the T3-Ti complex. Cell Immunol 1994; 156:286-95. [PMID: 7517794 DOI: 10.1006/cimm.1994.1175] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Ch7 (RGSDIAG), a synthetic heptapeptide derived from a conserved region of HIV p24 (aa 232-238), was previously shown to suppress antigen-induced responses in cultures of normal human peripheral blood lymphocytes (PBL). We show in this paper that Ch7 is the shortest peptide retaining full inhibitory capacity. Further, the peptide inhibited efficiently and in a dose-dependent manner the induction of a specific antibody response to the antigens SRC (sheep red cells) and Candida albicans but did not exert any effect on the induction of immunoglobulin-secreting cells in PWM-stimulated cultures. Finally, Ch7 inhibited anti-CD3-induced lymphoproliferation but did not affect anti-CD2 activation. These results suggest that a conserved epitope of HIV p24 may be able to prevent the induction of antigen-specific antibody responses by interfering with lymphocyte activation via the T3-Ti complex, resulting in the abrogation of immune functions that are defective in HIV-infected individuals.
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Affiliation(s)
- A L Luzzati
- Department of Immunology, Istituto Superiore di Sanità, Rome, Italy
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39
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Abstract
We have investigated the ability of APC Class II molecules to bind and release exogenous peptides, two phenomena that are still poorly understood. In order to investigate the half-life of the complex of an exogenous peptide with DR molecules we have evaluated the uptake and release of the radiolabeled peptide 17-29-Tyr of influenza virus matrix protein (MA 17-29-Y) by a B-EBV cell line at different times and under different conditions. We have found that the kinetics of both binding and release of the peptide are very fast in living cells; using glutaraldehyde-fixed cells, the kinetics of the two phenomena are slow, closely resembling those observed with the same peptide and purified, immobilized DR molecules. As confirmed by the study of a specific T-cell clone activation, the Class II-MA 17-29-Y complexes are short-living ones, with an average half-life of 55 min, and the DR molecules that bind exogenous peptides continuously undergo peptidic exchange. These data, taken together, suggest that the APC are endowed with cellular mechanisms that increase the efficiency of both the loading and the unloading of Class II HLA with exogenous peptides. These mechanisms do not appear to require ATP or to involve newly synthesized Class II molecules, intracellular acidic compartments, or the microtubule-microfilament system. On the other hand, an undamaged cell membrane appears to be crucial for an efficient binding.
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Affiliation(s)
- G Frumento
- Immunogenetica, Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy
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40
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Tanigaki N, Fruci D, Chersi A, Falasca G, Tosi R, Butler RH. HLA-A2-binding peptides cross-react not only within the A2 subgroup but also with other HLA-A-locus allelic products. Hum Immunol 1994; 39:155-62. [PMID: 8026983 DOI: 10.1016/0198-8859(94)90255-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Seven A2-binding peptides were tested by the HLA class I alpha-chain refolding assay previously described for their direct binding to HLA class I alpha chains derived from a panel of 18 HLA-homozygous B-cell lines of various HLA specificities, including four A2 subtypes: A*0201, A*0204, A*0205, and A*0206. All but one test peptide possessed the major anchor residue motifs, L-V, L-L, or I-L, of A2(A*0201)/A2(A*0205)-binding peptides or the closely related motifs, I-V or V-V. This cell panel analysis confirmed the high A2 allele specificity of the test peptides, but also revealed the existence of a broad cross-binding within the A2 subgroup. Most peptides bound to the alpha chains of the A2 subtypes tested, although their binding patterns showed differences. Furthermore, the A2-binding peptides carrying the I-V or V-V motif were found to cross-react also outside of the A2 subtypes, probably with A24, A26, A28, and A29. Other A-locus allelic products, A1, A3, A11, A30, and A31, and the B-locus allelic products carried by the cells tested were essentially negative, although a few exceptions were seen.
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Affiliation(s)
- N Tanigaki
- Institute of Cellular Biology, CNR, Rome, Italy
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41
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Cianfriglia M, Willingham MC, Tombesi M, Scagliotti GV, Frasca G, Chersi A. P-glycoprotein epitope mapping. I. Identification of a linear human-specific epitope in the fourth loop of the P-glycoprotein extracellular domain by MM4.17 murine monoclonal antibody to human multi-drug-resistant cells. Int J Cancer 1994; 56:153-60. [PMID: 7505264 DOI: 10.1002/ijc.2910560127] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A new murine monoclonal antibody (MAb), MM4.17, to human multi-drug-resistant (MDR) cells was found to be reactive in an ELISA with a synthetic 16-amino acid peptide selected from the fourth loop of the P-glycoprotein extracellular domain. Immunohistochemistry indicated that this MAb reacted in human tissues in the same pattern as that previously found with other human-specific MAbs to P-glycoprotein. For a precise definition of the MM4.17 epitope, a peptide library consisting of overlapping 4- to 10-mer residues covering the entire P-glycoprotein-fragment was synthesized on polyethylene pins and tested for MAb binding. The results of this ELISA demonstrated that the MM4.17 epitope is constituted by the continuous-linear TRIDDPET amino-acid sequence (residues 750-757 of the human MDRI-P-glycoprotein). The MAb MM4.17 recognizes only the human MDRI-P-glycoprotein isoform, and excess TRIDDPET peptide blocks the binding of the MAb to MDR variants of CEM cells. These results demonstrate that the amino-acid sequence TRIDDPET from the human MDRI gene represents the first continuous-linear epitope identified in the P-glycoprotein extracellular domain.
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Affiliation(s)
- M Cianfriglia
- Laboratorio di Immunologia, Istituto Superiore di Sanità, Roma, Italy
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42
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Fruci D, Rovero P, Falasca G, Chersi A, Sorrentino R, Butler R, Tanigaki N, Tosi R. Anchor residue motifs of HLA class-I-binding peptides analyzed by the direct binding of synthetic peptides to HLA class I alpha chains. Hum Immunol 1993; 38:187-92. [PMID: 8106276 DOI: 10.1016/0198-8859(93)90539-d] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The binding characteristics of the primary anchor residue motifs reported for HLA-A2 (A*0201, A*0205) and HLA-B27 (B*2705) alleles were investigated by a direct binding assay of the pertinent synthetic peptides to HLA class I alpha chains derived from a panel of HLA homozygous B-cell lines of various HLA phenotypes, including four A2 subtypes. The assay is based on a serologic detection of the conformational change of HLA class I alpha chains induced by binding to specific peptides in the presence of beta 2m. It is applicable to test a large number of HLA allelic products and synthetic peptides. Assay data confirmed the high allele specificity of the anchor residue motifs tested, but also revealed the intra- and interlocus cross-reactivity of these motifs. In the case of A2 anchor motifs, not only a broad cross-reactivity within the A2 subgroup, but also cross-reactivities with A24, A26, A28, and A29 were observed. With B27 anchor motifs, an interlocus cross-reactivity with A3 and A31 was seen. Several peptides, even though they carried A2 or B27 major anchor residue motifs, failed to bind to the relevant alpha chains, suggesting that the presence of a primary anchor residue motif is necessary for HLA class-I-peptide binding but is not by itself sufficient to guarantee binding.
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Affiliation(s)
- D Fruci
- Institute of Cellular Biology, CNR, Rome, Italy
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43
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Buzzetti R, Nisticò L, Osborn JF, Giovannini C, Chersi A, Sorrentino R. HLA-DQA1 and DQB1 gene polymorphisms in type I diabetic patients from central Italy and their use for risk prediction. Diabetes 1993; 42:1173-8. [PMID: 8325449 DOI: 10.2337/diab.42.8.1173] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Susceptibility to type I diabetes has been shown to be highly correlated with the presence of an amino acid other than Asp at position 57 of the DQ beta-chain (non-Asp57) and also with the presence of an Arg at position 52 of the DQ alpha-chain (Arg52). In this study we analyzed the DQA1 and DQB1 gene polymorphisms in 65 patients from central Italy and 93 randomly selected control subjects. Polymerase chain reaction amplification of DNA encoding the first polymorphic domain of the DQB1 and DQA1 chains was performed, and DQB1 gene polymorphism was evaluated by dot blot analysis using 11 sequence-specific oligonucleotide probes. For DQA1 typing, a new simple procedure based on allele-specific amplification and analysis of heteroduplex DNA molecules formed by the annealing of mismatched allelic strands was used. This technique allows the discrimination of Arg52 and non-Arg52 DQA1 alleles. We then calculated by logistic regression the contribution of these genetic markers to the development of diabetes. Frequencies and odds ratios relative to the amino acid in position 57 of the DQ beta-chain and the amino acid in position 52 of the DQ alpha-chain showed that the highest odds ratio (odds ratio = 161; 95% confidence interval 19-1386) was that of the homozygous combination of the two susceptibility markers (non-Asp57 and Arg52).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R Buzzetti
- Institute of Cell Biology, Italian National Research Council, Rome
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44
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Castiglione S, Fanciulli M, Bruno T, Evangelista M, Del Carlo C, Paggi MG, Chersi A, Floridi A. Rhein inhibits glucose uptake in Ehrlich ascites tumor cells by alteration of membrane-associated functions. Anticancer Drugs 1993; 4:407-14. [PMID: 8358069 DOI: 10.1097/00001813-199306000-00019] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Rhein (RH), 4,5 dihydroxyanthraquinone-2-carboxylic acid, is known to inhibit the glycolysis of neoplastic cells by impairing glucose uptake. In order to establish whether this might be due to a selective interaction of the carrier with the drug or to functional modifications of the cell membrane, the effect of RH on glucose uptake in Ehrlich ascites tumor cells has been investigated. RH strongly inhibits the uptake of both 2-deoxyglucose and 3-O-methylglucose, so the reduced influx therefore cannot be ascribed to an effect on glucose phosphorylation. The inhibition of glucose transport does not depend on a reduction of the number of the carriers as indicated by the inability of the drug to interfere with the synthesis of the transporter. Moreover, the extent of total binding of cytochalasin B, as well as the fact that glucose specificity is not altered, indicate that the intrinsic activity of the glucose carrier is not affected. We therefore conclude that the inhibition of glucose uptake must be ascribed to an interaction of the drug with cell membranes that results in an alteration of membrane-associated functions.
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Affiliation(s)
- S Castiglione
- Laboratory for Cell Metabolism and Pharmacokinetics, Regina Elena Institute for Cancer Research, Rome, Italy
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45
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Abstract
Unfolded HLA class I alpha chains were isolated from B-cell lysates by alkaline denaturation and subsequent gel filtration and used for the detection of HLA class-I-peptide binding. Binding to specific peptides in the presence of excess beta 2-microglobulin induced the unfolded alpha chains to refold and acquire a conformation that is specific to folded alpha chains. This conformational change was measured by a specific RIA that involves inhibition of the binding of 125I-labeled HLA-A2 alpha/beta dimers and rabbit anti-HLA-B7 serum absorbed with beta 2-microglobulin. This assay procedure does not require labeling of either test peptides or test class I proteins and does not seem to have specificity degeneracy. It is applicable to the detection of peptide binding by all HLA class I allelic proteins. Evaluation of the assay conditions and HLA allelic specificity of the peptide binding defined by the use of synthetic peptides are described here, including the technical details, specificity, and reproducibility.
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Affiliation(s)
- N Tanigaki
- Institute of Cellular Biology, CNR, Rome, Italy
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46
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Fruci D, Rovero P, Chersi A, Sorrentino R, Butler R, Tanigaki N, Tosi R. Anchor residue motifs of HLA class I-binding peptides analysed by the direct binding of synthetic peptides to HLA class I alpha chains. Hum Immunol 1993. [DOI: 10.1016/0198-8859(93)90104-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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47
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Pugliese O, Viora M, Camponeschi B, Cordiali Fei P, Caprilli F, Chersi A, Evangelista M, Di Massimo AM, Colizzi V. A gp120 HIV peptide with high similarity to HLA class II beta chains enhances PPD-specific and autoreactive T cell activation. Clin Exp Immunol 1992; 90:170-4. [PMID: 1424270 PMCID: PMC1554595 DOI: 10.1111/j.1365-2249.1992.tb07923.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The recent report that anti-gp120 antibodies can be induced by allogeneic stimuli in experimental animals in the absence of HIV, has focused attention on the structural similarities between gp120 and MHC. Here we report that some HIV+ individuals develop antibodies which similarly react with the gp120 HIV sequence (aa 254-263) and with the HLA-DR beta chains (aa 142-151). As these two peptides share a high level of similarity, we have investigated the role of this gp120 region on HLA class II mediated T cell recognition. The synthetic peptide corresponding to the gp120 HIV sequence aa 254-263 has been tested on T cell line (TCL) activation. Both the PPD-specific and the self-HLA reactive TCL proliferation increased in the presence of this peptide. Prepulsing experiments indicate that this enhancing effect carried out by HIV peptide is exerted at the level of antigen presentation. Moreover, the specificity of this interaction is supported by the fact that a MoAb specific for this HIV peptide blocked the autoreactive TCL proliferation, similarly to the inhibition carried out by anticlass II antibody. These data support the hypothesis that the functional homology between the HIV peptide and the HLA beta chain described may be involved in the pathogenesis of AIDS.
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Affiliation(s)
- O Pugliese
- Istituto Superiore di Sanità, Università di Tor Vergata, Rome, Italy
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48
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Luzzati AL, Giacomini E, Giordani L, Pugliese O, Viora M, Chersi A. The antigen-specific induction of normal human lymphocytes in vitro is down-regulated by a conserved HIV p24 epitope. Immunol Lett 1992; 33:307-14. [PMID: 1385321 DOI: 10.1016/0165-2478(92)90078-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Synthetic peptides containing amino acid sequence 218-238 of the core protein p24 of human immunodeficiency virus type 1 (HIV-1) and progressively shorter sequences at its C-terminus, were tested for their effect on antigen dependent in vitro responses of peripheral blood lymphocytes (PBL) from normal human donors. A peptide as short as 7 amino acids, corresponding to a highly conserved sequence, was able to inhibit in a dose-dependent manner the induction of a specific primary antibody response to the sheep red cell (SRC) antigen, as well as the proliferative response to recall microbial antigens. The results of this study constitute additional evidence of the immunoinhibitory effects of HIV components and may help to unravel some of the pathogenic mechanisms of AIDS. Moreover, they are of potential relevance for the development of immunoprophylactic and therapeutic strategies.
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Affiliation(s)
- A L Luzzati
- Department of Immunology, Istituto Superiore di Sanità, Rome, Italy
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49
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Romano TF, Evangelista M, Castelli M, Chersi A. Preparation of tissue polypeptide antigen (TPA) from sera pools of cancer patients. Cancer Biochem Biophys 1991; 12:205-9. [PMID: 1844912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
TPA is a tumor marker characteristic of general cellular proliferation. High serum levels are found in patients with tumor progression. With the aim of bettering the clinical use, the authors have isolated TPA in purer form, in order to develop, in the future, a more specific immunoenzymatic method based on unlabeled antipeptide antibodies. A simple method for the isolation of small amounts of tissue polypeptide antigen (TPA) from the sera of patients suffering from neoplastic diseases is described. The procedure takes advantage of the availability of commercial anti-TPA coated beads; sera pools with high levels of antigen are allowed to react with such beads, then the antibody-antigen complex is dissociated by drastic changes of pH or molarity, and TPA recovered. Such TPA preparations contain low amounts of extraneous proteins, and thus can be utilized in immunoenzymatic tests, or in laboratory investigations.
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Affiliation(s)
- T F Romano
- Regina Elena Institute for Cancer Research, Rome, Italy
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50
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Chersi A, Romano TF, Evangelista M, Mileo AM, Falasca G. Preparation of rabbit antibodies to 4,4'-dimethoxytriphenylmethyl, the protective group in oligonucleotide synthesis. Biol Chem Hoppe Seyler 1991; 372:845-8. [PMID: 1772597 DOI: 10.1515/bchm3.1991.372.2.845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Antibodies were raised in 2 rabbits by immunization with carrier proteins covalently bound to deoxyguanosine bearing a 4,4'-dimethoxytriphenylmethyl group protecting the 5'-hydroxy terminus of deoxyribose. After several injections with such complexes, immune sera were tested with an immuno-enzymatic method using as antigens several compounds containing the hapten, as well as synthetic oligonucleotides bearing, or not, this protective group at the 5' terminus. One of the two antisera appeared to recognize the dimethoxytrityl group bound to carrier molecules, and thus might find a useful application for the detection, quantitation, and control of oligonucleotides obtained by automatic synthesis.
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Affiliation(s)
- A Chersi
- Laboratory of Biochemistry, Regina Elena Institute for Cancer Research, Rome
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