Identification of the blood group Lewisadeterminant in the oviducal mucins ofXenopus tropicalis

The amphibian Xenopus tropicalis appears an increasingly appealing model for both genetic and developmental biology studies, compared to the related species Xenopus laevis. Study of the glycosylation pattern of its secreted glycoproteins revealed that this species synthesizes large amounts of Lewis(a) epitope, whereas this motif has previously only been identified in animals within the primate lineage. The use of (1)H-nuclear magnetic resonance spectroscopy enabled us to resolve the sequence of three Lewis(a)-bearing O-linked glycans associated with oviducal secretions, out of which one contained the novel sequence Gal(beta 1-3)GlcNAc(beta 1-6)GalNAc-ol. These structural data suggested the emergence of an alpha 1,4-fucosyltransferase activity in animals outside the primate lineage. On this basis, the screening of a X. tropicalis GenBank database with human Lewis-fucosyltransferase sequences revealed the occurrence of a putative fucosyltransferase gene that presented an unusual acceptor motif.

A preclinical study comparing approaches for augmenting the immunogenicity of a heptavalent KLH-conjugate vaccine against epithelial cancers

Previously using a series of monovalent vaccines, we demonstrated that the optimal method for inducing an antibody response against cancer cell-surface antigens is covalent conjugation of the antigens to keyhole limpet hemocyanin (KLH) and the use of a saponin adjuvant. We have prepared a heptavalent-KLH conjugate vaccine containing the seven epithelial cancer antigens GM2, Globo H, Lewis(y), TF(c), Tn(c), STn(c), and glycosylated MUC1. In preparation for testing this vaccine in the clinic, we tested the impact on antibody induction of administering the individual conjugates plus adjuvant compared with a mixture of the seven conjugates plus adjuvant, and of several variables thought to augment immunogenicity. These include approaches for decreasing suppressor cell activity or increasing helper T-lymphocyte activity (low dose cyclophosphamide or anti-CTLA-4 MAb), different saponin adjuvants at various doses (QS-21 and GPI-0100), and different methods of formulation (lyophilization and use of polysorbate 80). We find that: (1). Immunization with the heptavalent-KLH conjugate plus GPI-0100 vaccine induces antibodies against the seven antigens of comparable titer to those induced by the individual-KLH conjugate vaccines, high titers of antibodies against Tn (median ELISA titer IgM/IgG 320/10240), STn (640/5120), TF (320/10240), MUC1 (80/20480), and globo H (640/40); while lower titers of antibodies against Lewis(y)()(160/0) and only occasional antibodies against GM2 are induced. (2). These antibodies reacted with the purified synthetic antigens by ELISA, and with naturally expressed antigens on the cancer cell surface by FACS. (3). None of the approaches for further altering the suppressor cell/helper T-cell balance nor changes to the standard formulation by lyophilization or use of polysorbate 80 had any impact on antibody titers. (4). An optimal dose of saponin adjuvant, QS-21 (50 microg) or GPI-0100 (1000 microg), is required for optimal antibody titers. This heptavalent vaccine is sufficiently optimized for testing in the clinic.

Modulation of MUC1 and blood group antigen expression in gastric adenocarcinoma cells by cytokines

Immunohistological studies demonstrated that MUC1 expression in gastric cancer is associated with a poor prognosis. As a mediator of cell-cell interactions, MUC1 may also be involved in metastasis. However, these aspects are of relevance since cytokine levels are locally increased as a consequence of peritumorous inflammatory response and coexisting chronic gastritis. Therefore we analyzed the potential influence of several cytokines on the expression of tumor-associated MUC1 and Lewis blood group antigens in gastric carcinoma cells. Gastric cancer cell lines AGS and KATOIII were incubated with the cytokines interleukin-1beta, interferon-gamma, tumor necrosis factor-alpha (TNF-alpha), and hepatocyte growth factor over a period of 72 h. Expressions of mucin antigens and cytokine secretion were measured by immunocytochemistry and/or enzyme-linked immunosorbent assay (ELISA). Analysis by fluorescence-activated cell sorter (FACS) demonstrated that MUC1 and sialyl Lewis A reactivities of AGS cells were increased significantly following TNF-alpha stimulation but not by other cytokines. Expression of mucin-associated antigens by cell line KATOIII was not affected by any of the employed cytokines. These data provide evidence that TNF-alpha can raise the expression of important mucin peptide as well as mucin-associated carbohydrate antigens and thereby potentially influence the progression of gastric carcinomas.

The relationship between oral Candida carriage and the secretor status of blood group antigens in saliva

OBJECTIVE

The aim of the study was to investigate the relationship between oral Candida carriage and the secretor status of blood group antigens.

STUDY DESIGN

Unstimulated whole saliva and oral rinse samples were obtained from 180 healthy subjects. These samples were plated on Sabouraud's dextrose agar media to determine oral Candida carriage. Sodium dodecylsulfate polyacrylamide gel electrophoresis and immunoblotting were performed on whole saliva samples to determine the secretor status of blood group antigens.

RESULTS

The oral Candida carriage rate was found to be 45.0%. The sensitivity of the concentrated rinse culture proved to be superior. Oral Candida carriage was not significantly related to the blood group or secretor status of ABH or Lewis antigens. No significant relationship was found between oral Candida carriage and salivary flow rate. However, smoking affected oral Candida carriage.

CONCLUSION

Oral Candida carriage in healthy individuals is not significantly related to blood group or secretor status.

Noncovalent scFv multimers of tumor-targeting anti-Lewis(y) hu3S193 humanized antibody

Single-chain variable fragments (scFvs) of anti-Lewis(y) hu3S193 humanized antibody were constructed by joining the V(H) and V(L) domains with either +2 residues, +1 residue, or by directly linking the domains. In addition two constructs were synthesized in which one or two C-terminal residues of the V(H) domain were removed (-1 residue, -2 residue) and then joined directly to the V(L) domain. An scFv construct in the reverse orientation with the V(L) joined directly to the V(H) domain was also synthesized. Upon transformation into Escherichia coli all scFv constructs expressed active protein. Binding activity, multimeric status, and multivalent properties were assessed by flow cytometry, size exclusion chromatography, and biosensor analysis. The results for hu3S193 scFvs are consistent with the paradigm that scFvs with a linker of +3 residues or more associate to form a non-covalent dimer, and those with a shorter linker or directly linked associate predominantly to form a non-covalent trimer and tetramer that are in equilibrium. While the association of V domains to form either a dimer or trimer/tetramer is governed by the length of the linker, the stability of the trimer/tetramer in the equilibrium mixture is dependent on the affinity of the interaction of the individual V domains to associate to form the larger Fv module.

Cancer-homing toxins

Cancer-homing toxins are a group of man-made cytotoxic molecules targeting cancer cells. In the past decade they have demonstrated potential as cancer therapeutics. These molecules contain a toxin, natural or usually derivatized, connected to a cancer-homing module, such as a monoclonal antibody or growth factor or their derivatives. Various cancer-homing toxins have been designed and tested in cell-lines, animal-models and clinical trials. We review some of these data and discuss ways to better design cancer-homing toxins in the light of advances in cancer genomics, antibody-engineering techniques and computational algorithms.

Bovine anti-Helicobacter pylori antibodies for oral immunotherapy

BACKGROUND

Passive immunization with orally administered antibodies against specific pathogens has previously been successfully used therapeutically in both animal and human studies. We employed a similar strategy for experimental treatment of mice infected with the gastric pathogen Helicobacter pylori.

METHODS

An anti-H. pylori bovine colostral hyperimmune immunoglobulin preparation (BIC) was generated and its efficacy was tested in different in vitro experiments, such as binding to the Lewis(b) blood group antigen, inhibition of adherence of H. pylori to human gastric mucosa tissue sections in situ and in a haemagglutination assay. The BIC preparation was also given in the drinking water to H. pylori-infected mice.

RESULTS

An inhibition of 95% of the binding of H. pylori to Lewis(b) glycoconjugate was observed in vitro. Furthermore, a blocking activity of almost 90% was observed when the BIC was preincubated with H. pylori bacteria. Finally, the BIC preparation inhibited the haemagglutination of H. pylori and human red blood cells. Seven of 40 (17.5%) mice remained infected in the treatment group as compared with 25 of 45 (55.5%) in the control group. Hence, the cure rate was 66%, P = < 0.001. The mean number of colonies in the antibody-treated mice where eradication was not successful was also reduced (P < 0.05). In trials using FVB/N transgenic Lewis(b) expressing mice, a cure rate of 50%-66% was observed.

CONCLUSION

Bovine colostral antibodies against H. pylori can be generated in high titres, inhibit binding in vitro and can eradicate or reduce the number of bacteria in infected mice.

Lectins as markers for blood grouping

Lectins are unique proteins of varying biological importance. They are characterized by specific binding to carbohydrate residues, whether monosaccharides, disaccharides or polysaccharides. The sugar heads on the surface of the erythrocyte specify the different blood groups. Lectins, as an antigenic determinant of blood group, have come to be an important tool in the identification of different blood groups. A handful of lectins may be considered excellent reagents for anti-A, anti-B, anti-N etc, but the anti-A and anti-M are not yet regarded as commercially suitable antisera. Lectin from Vicia cracca has been proved to be a good anti-A, lectin from Dolichus biflorus can be used as anti-A1, and lectin from Griffonia simplicifolia as anti-B. Lectin from Vicia graminea is said to be a good typing reagent as Anti-N. On the other hand, the lectins involved in polyagglutination are absolutely essential as the reagent of choice and these cannot as yet be replaced by antibodies of any kind. Erythrocytes with exposed cryptantigens are significantly more sensitive to agglutination by certain lectins than by polyclonal antibodies. Peanut agglutinin (PNA), Polybrene, and Glycine max lectins are frequently used for the identification of different cryptantigens. The application of lectins as an anti-B reagent has proven to be as useful as human polyclonal or mouse monoclonal antibodies. Besides their specificity, lectins are excellent reagents because of their lower cost and indigenous production. The importance of various lectins used as markers for blood grouping is discussed.

Glucocorticoid-induced differential expression of the sialylated and nonsialylated Lewis(a) epitopes and respective binding sites in human nasal polyps maintained under ex vivo tissue culture conditions

We characterized the anti-inflammatory effects of budesonide on the expression of adhesion molecules involving Lewis(a) (Le(a)) epitope, its sialylated derivative (sLe(a)), and their respective binding sites in human nasal polyposis. By computer-assisted microscopy, we quantitatively characterized the level of histochemical expression of L- and P-selectins, sialylated and nonsialylated Le(a) epitopes, and their respective binding sites in both surface epithelium and glandular epithelium of human nasal polyps obtained from surgical resection, maintained under ex vivo tissue culture conditions for 24 hours, and treated or not with budesonide. Intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) were chosen as methodological controls, because data already published in the literature clearly indicated budesonide-mediated effects on ICAM-1 and VCAM-1 levels of expression. The present data show that budesonide significantly modified the levels of expression of ICAM-1 and VCAM-1, and to a lesser extent that of P-selectin, in the surface and glandular epithelia. Budesonide markedly decreased the levels of expression of the binding sites for both Le(a) and sLe(a), while those of Le(a) and sLe(a) remained globally unchanged. In conclusion, the present study documents that glucocorticoid-induced effects can encompass receptors for Le(a) epitopes different from E- and P-selectins on epithelial cells of human nasal polyps.

Synthesis of tumor-associated glycopeptide antigens

Carbohydrates and peptides linked together in glycoproteins constitute important components of the molecular communication between cells in multicellular organisms. Cell morphogenesis and tumorigenesis are accompanied by changes in the glycoprotein profiles of the outer cell membranes. Glycopeptide fragments of glycoproteins that have altered structures in tumor cells are of interest as tumor-associated antigens for the distinction between normal cells and tumor cells. In contrast to glycoproteins isolated from biological sources, synthetic glycopeptides are obtained in pure form and exactly specified structures. The methods developed for the synthesis of glycopeptides with tumor-associated antigen structure are outlined in this article by means of a series of typical examples. Beginning with O-glycopeptides of the relatively simple alpha-O-galactosamine-serine/threonine (T(N)-antigen) type, glycopeptide antigens of increasing complexity are described. The review includes syntheses of the saccharide components, the glycosylation reactions to furnish the O-glycosyl amino acid building blocks, their selective C- and N-terminal deprotection and the use of these building blocks for glycopeptide syntheses both in solution and on the solid support. Particular attention is given to glycopeptides containing sialic acid residues, whose syntheses are demanding since reversible protection of the sialic carboxylic group is required. Synthetic methods for the construction of N-glycopeptides carrying the important cell adhesion ligands sialyl Lewis x and sialyl Lewis a antigen are also described. Strategies for the construction of glycopeptides of this type require methods compatible with the presence of the sialic acid residue, as well as with the acid-sensitivity of the fucoside bonds.

A phase I trial of the single-chain immunotoxin SGN-10 (BR96 sFv-PE40) in patients with advanced solid tumors

PURPOSE

Our purpose in the study was to establish the maximum tolerated dose and toxicity profile of SGN-10 (or BR96 sFv-PE40), a single-chain immunotoxin. SGN-10 is composed of the fused gene products encoding the translocating and ADP-ribosylating domains of Pseudomonas exotoxin (PE40) and the variable heavy (V(H)) and variable light (V(L)) regions of BR96 monoclonal antibody. This antibody is specific for a Lewis(Y) (Le(Y))-related carbohydrate antigen expressed on multiple carcinomas.

EXPERIMENTAL DESIGN

A total of 46 patients with Le(Y)-positive metastatic carcinoma were enrolled in a Phase I dose-escalation study in cohorts of three to six patients who received SGN-10 at doses ranging from 0.024 to 0.962 mg/m(2), administered on days 1, 4, 8, and 11, followed by 2 weeks of rest and a second cycle of therapy. Pharmacokinetics and human antibody response to SGN-10 were also determined.

RESULTS

The maximum tolerated dose of SGN-10 was 0.641 mg/m(2) with gastrointestinal dose-limiting toxicity. Pharmacokinetic studies performed in eight patients at the 0.641-mg/m(2) dose revealed a t([1/2]) of 2.5 +/- 0.3 h and a C(max) of 389 +/- 112 ng/ml. Pharmacodynamic analyses demonstrated a rapid clearance of the drug by day 11 associated with an antitoxin human antitoxin antibody (HATA) response in most patients. Signs consistent with a modest vascular leak syndrome, specifically, transient hypoalbuminemia, were observed in patients treated with doses of > or =0.384 mg/m(2). No complete or partial tumor responses were observed at an 8-week evaluation, although 31% of patients had stable disease.

CONCLUSIONS

The maximal tolerated dose of SGN-10 given twice weekly for 2 weeks is 0.641 mg/m(2) with gastrointestinal dose-limiting toxicity. The immunogenicity of the toxin moiety limits the ability of SGN-10 to circulate by day 11 of therapy. Studies are ongoing to evaluate strategies to ameliorate toxicities and to inhibit the development of the anti-SGN-10 immune response.

Cathepsin B-labile dipeptide linkers for lysosomal release of doxorubicin from internalizing immunoconjugates: model studies of enzymatic drug release and antigen-specific in vitro anticancer activity

The anticancer drug doxorubicin (DOX) has been linked to chimeric BR96, an internalizing monoclonal antibody that binds to a Lewis(y)-related, tumor-associated antigen, through two lysosomally cleavable dipeptides, Phe-Lys and Val-Cit, giving immunoconjugates 72 and 73. A self-immolative p-aminobenzyloxycarbonyl (PABC) spacer between the dipeptides and the DOX was required for rapid and quantitative generation of free drug. DOX release from model substrate Z-Phe-Lys-PABC-DOX 49 was 30-fold faster than from Z-Val-Cit-PABC-DOX 42 with the cysteine protease cathepsin B alone, but rates were identical in a rat liver lysosomal preparation suggesting the participation of more than one enzyme. Conjugates 72 and 73 showed rapid and near quantitative drug release with cathepsin B and in a lysosomal preparation, while demonstrating excellent stability in human plasma. Against tumor cell lines with varying levels of BR96 expression, both conjugates showed potent, antigen-specific cytotoxic activity, suggesting that they will be effective in delivering DOX selectively to antigen-expressing carcinomas.

Constructing an adenocarcinoma vaccine: immunization of mice with synthetic KH-1 nonasaccharide stimulates anti-KH-1 and anti-Le(y) antibodies

There is mounting evidence to suggest that immunization-based strategies can be used to mobilize the human immune system against specific carbohydrate antigens displayed on the surface of cancer cells. Following isolation and identification, such antigens can be administered as conjugate vaccines. The tumor-associated carbohydrate antigen KH-1 is 1 such antigen and may serve as a potential target for immunization against adenocarcinoma. However, a serious impediment to the application of a vaccine-based approach involving this antigen is that its availability from natural sources is severely limited. In order to overcome this limitation, we have developed an efficient total synthesis of this complex glycolipid. We have extended our synthesis to reach a structurally related analog in which the ceramide portion of KH-1 is replaced with an allyl substituent. These synthetic advances have led to the preparation of 2 potential vaccine constructs, each based on the conjugation of the KH-1 nonasaccharide and the carrier protein keyhole limpet hemocyanin (KLH). In 1 construct (KH-1-Et-KLH), the nonasaccharide is conjugated to KLH via a simple ethyl linkage, while in the other (KH-1-MMCCH-KLH), conjugation is mediated by a 4-(4-N-maleimidomethyl)cyclohexane-1-carboxyl hydrazide (MMCCH) cross-linker. We report here the immunological properties of these 2 constructs. Mice were immunized with either of the 2 KH-1-KLH vaccine candidates or the KH-1 ceramide, along with the immunological adjuvant QS-21. Immunization with the ceramide served as a negative control and, as expected, failed to stimulate the production of antibodies against the KH-1 glycolipid. The construct in which the KH-1 nonasaccharide is linked to KLH via a simple alkyl chain stimulated significant quantities of IgM antibodies, whereas the construct linked to KLH by MMCCH induced high titers of both IgM and IgG antibodies. Inhibition data demonstrated that antibodies generated in response to immunization with the KH-1-KLH constructs recognize not only the KH-1 antigen but also the Lewis(y) (Le(y)) antigen, which, from a structural perspective, is similar to the 4 residues located at the non-reducing end of the KH-1 nonasaccharide. Thus, the KH-1-KLH constructs elicit an immune response that successfully targets 2 adenocarcinoma markers. As assessed by FACS analysis, the antibodies raised were strongly reactive with the KH-1/Le(y) positive cell line MCF-7 but not with KH-1 and Le(y) negative melanoma cell lines. Based on the results of our study, a KH-1-KLH plus QS-21 vaccine is being prepared for clinical evaluation.

[Antigenic differentiation of blood stains by the Lewis system in practical forensic medical expert evaluation]

A modification of quantitative absorption and absorption elution tests with blood stain washing before the absorption phase is presented. Due to washing, the effect of carrier object on anti-Le(a) and anti-Le(b) sera is decreased and the sensitivity of the method is increased. Additional adsorption of the sera and elution into test erythrocytes treated with protease C is suggested for increasing the number of standard sera fit for the absorption-elution test. A new technology for preparing anti-Le(a) and anti-Le(b) immunoreagents is described.

[Effects of Lewis Y oligosaccharide on secretion and gene expression of EGF and EGF-R in mouse embryos]

Implantation is a complicated developmental process. Some hormones and cytokines are involved in the regulation of the implantation by regulating functions of the endometrium and the embryo. Oligosaccharide antigen Lewis Y is specifically expressed on embryo surface and plays an important role in implantation. In this study, effects of Lewis Y on secretion and gene expression of EGF and EGF receptor of the embryo were investigated. Embryos were pre-incubated with Le(Y) specific antibody AH6 for 3 h, then antibody was removed, immuno-dot blots and RT-PCR were used to analyze the secretion of EGF and EGF receptor and their gene expression in the embryo at different times after pre-incubation. The results showed that, when blocked by AH6 antibody for 1.5 h, the secretion and expression of EGF in the embryo were significantly declined, and the alteration was continued to over 6 h; and those of EGF-R were slightly decreased after blocking. The results suggest that Lewis Y oligosaccharide on the surface of embryo may be involved in the regulation of embryo development and implantation, by affecting the expression and secretion of EGF in embryo.

Use of surrogate antigens as vaccines against cancer

Tumor cells may evade immune surveillance by possessing polysaccharides or carbohydrates on their surface. This evasive strategy is effective because glycans are poorly immunogenic and fail to elicit immunological memory responses due to an absence of T-cell processing. Induction of an immune response to cell surface carbohydrate antigens is considered as an important strategy to fight cancer. As carbohydrates per se are poor immunogens, alternative approaches are being evaluated to induce functional cross-reactive responses. We are focusing on the use of peptide mimotopes of tumor-associated carbohydrate antigens to challenge cancer, as we would manipulate the immune system to establish protective immunity based on carbohydrate cross-reactive humoral and cellular responses.

Detection of ligands for selectins in the oligosaccharide fraction of human milk

BACKGROUND

Human milk contains a large variety of oligosaccharides which show struc tural similarities with ligands for selectins, a family of cell adhesion molecules which are involved in many cell-cell interactions.

AIM OF THE STUDY

Due to their structural similarity with selectin ligands, human milk oligosaccharides were labelled with phosphatidyl ethanolamine to be able to investigate specific effects of antibodies against carbohydrate epitopes.

METHODS

Various monoclonal antibodies against physiological selectin ligands were used to determine whether epitopes within human milk oligosaccharides are recognized. Oligosaccharides were isolated from human milk, transferred into neoglycolipids and separated using high performance thin layer chromatography prior to incubation with monoclonal antibodies for the selectin ligands sialyl-Lewis a (sLe a), sialyl-Lewis x (sLe x), Lewis x (Le x) and Lewis y (Le y) after Western blotting. Fast atom bombardment-mass spectrometry was then used to identify antibody-binding compounds. Results In the immunoassays all ligand epitopes except for Le y were detected in the oligosaccharide fraction of human milk. Anti-sLe a showed the most distinct reaction with N-acetylneuraminic acid containing neoglycolipids of which two were identified as neuraminylfucosyl-lacto-N-hexaose and neuraminyl-lacto-N-tetraose. Such oligosaccharides as well as similar structures are present in relatively high concentrations in human milk.

CONCLUSIONS

The presence of sialyl-Lewis ligands on milk oligosaccharides together with their abundancy in human milk may suggest that they could be selectin ligands and they may be part of inflammatory processes.

The Helicobacter pylori blood group antigen-binding adhesin facilitates bacterial colonization and augments a nonspecific immune response

Presence of the Helicobacter pylori adherence factor blood group Ag-binding adhesin (BabA; binding to Lewis(b) (Le(b))) is associated with ulcer disease, adenocarcinoma, and precancerous lesions. The importance of BabA for bacterial colonization and the inflammatory response is unknown. A total of 141 antral biopsies from H. pylori-infected patients were assessed in regard to the degree of granulocytic (G0 degrees--G3 degrees) and lymphocytic (L1 degrees--L3 degrees) infiltration. DNA genotypes of babA2 (the transcriptionally active gene of BabA), cagA, and vacAs1/2 were determined by PCR. Colonization density and Le(b) status on gastric epithelial cells were determined by immunohistochemistry. Real-time quantitative (TaqMan) RT-PCR determined mRNA expression of IL-8, TNF -alpha, and the Th1 markers IFN-gamma and the IL-12R beta2 chain. A total of 91% of infected patients were Le(b) positive. The vacAs1(+)/cagA(+) strains harboring babA2 showed significantly higher levels of granulocytic infiltration, bacterial colonization, and IL-8 mRNA than vacAs1(+)/cagA(+) strains lacking babA2. IL-8 mRNA and protein production by KATO III cells in vitro increased dose dependently with addition of different numbers of type 1 strains (G27 and 2808 strains, 0.1--20 bacteria/cell). The mRNA expression of TNF-alpha, IFN-gamma, and IL-12R beta2 was higher in H. pylori-positive patients than in controls, but it did not differ significantly between patients infected with different strain types. These data suggest that BabA facilitates colonization of H. pylori and thereby increases IL-8 response, resulting in enhanced mucosal inflammation. Infection with strains harboring BabA thereby augment a nonspecific immune response, whereas the Th1 response toward H. pylori appears to be independent of BabA, cytotoxin-associated gene A, or vacuolating cytotoxin.

Comparison of antibody titers after immunization with monovalent or tetravalent KLH conjugate vaccines

Antigens such as ganglioside GD3, neutral glycolipid Lewis(y) (Le(y)) and mucins MUC1 and MUC2 are over-expressed on the cell surface of many tumors. We have shown previously that conjugation of antigens such as these to keyhole limpet hemocyanin (KLH) and the use of immunological adjuvant QS-21 is the optimal approach for inducing high titer IgM and IgG antibodies. These antibodies are able to bind with natural antigens on the tumor cell surface and mediate complement dependent cytotoxicity and/or antibody dependent cell mediated cytotoxicity. Immunization of patients with monovalent vaccines containing these and a variety of other antigens have demonstrated both the consistent immunogenicity and the safety of these vaccines. Now, in preparation for the use of polyvalent conjugate vaccines in the clinic, we have addressed for the first time with conjugate vaccines against cancer antigens several questions in the pre-clinical setting, including whether immunogenicity of the individual components is decreased in the polyvalent vaccine and issues relating to vaccine formulation and administration. We have immunized groups of mice with GD3-KLH, Le(y)-KLH, MUC1-KLH and MUC2-KLH conjugates and QS-21 separately or mixed and administered at one or four sites. High titer IgM and IgG antibodies were induced against each of the four antigens whether administered singly in separate mice, at separate sites in the same mice, or mixed and administered at a single site or at four sites, or administered subcutaneously (s.c.) or intraperitoneally (i.p.). These antibodies reacted specifically with the respective antigens and tumor cells expressing these antigens. There was no evidence of suppression of the antibody response against any one of the antigens by the presence of the other conjugates in the vaccine. Immunogenicity of the four individual antigens conjugated to KLH and QS-21 is not affected by mixing the four together and administering them at a single subcutaneous site.

Immunoreactivity of Lewis blood group and mucin peptide core antigens: correlations with grade of dysplasia and malignant transformation in the colorectal adenoma-carcinoma sequence

Previous studies on the immunoreactivity of various mucin peptide and carbohydrate antigens in neoplastic colorectal tissues led to at least in part contradictory results. Therefore, we investigated a series of 42 adenomas and 44 carcinomas applying monoclonal antibodies (mabs) directed against Lewis blood group antigens (sialyl-Le(a), Le(x), sialyl-Le(x), Le(y)) as well as mucin peptide cores (MUC1, MUC2 and MUC5AC) by immunohistochemistry. A statistically significant positive correlation between the development of high-grade dysplasia in colorectal adenomas and the immunoreactivity of Le(y) and MUC1 epitopes was observed, whereas MUC2 exhibited a significant negative correlation. The reactivity of the other epitopes did not show an association with the progression of malignant transformation. Colorectal carcinomas were subdivided according to their histopathological subtype. The immunohistochemical staining resulted in a significantly stronger MUC2 reactivity of mucinous vs. tubular adenocarcinomas. Immunoreactivity of the MUC1-specific mab, which does not react with the fully glycosylated peptide core, showed a statistically non-significant inverse tendency, whereas all carbohydrate antigens displayed a strong expression in both tumor subtypes. Furthermore, correlations between mucin peptide and carbohydrate epitope labelling were evaluated. Progression of the adenoma-carcinoma sequence was accompanied by an increase of Le(y) as well as MUC1 antigen and an increase of all Lewis antigens compared to MUC2 immunoreactivity. On the other hand, mucinous carcinomas exhibited an inverse pattern. In conclusion, these results demonstrate that Le(y) and MUC1 immunoreactivity correlate with malignant transformation in the colorectum, whereas MUC2 represents a marker for low-grade dysplasia and the subtype of mucinous carcinomas.

Congenital nonprogressive hemangioma: a distinct clinicopathologic entity unlike infantile hemangioma

BACKGROUND

Infantile hemangiomas are common tumors, distinctive for their perinatal presentation, rapid growth during the first year of life, and subsequent involution-and for their expression of a unique immunophenotype shared by placental microvessels. Occasional "hemangiomas" differ from the classic form in presenting fully formed at birth, then following a static or rapidly involuting course. These congenitally fully developed lesions have generally been assumed to be clinical variants of more typical, postnatally developing hemangiomas. This assumption has not been tested by rigorous histologic and immunophenotypic comparisons.

OBJECTIVE

To compare the histologic and immunohistochemical features of congenital nonprogressive hemangiomas with those of typical, postnatally proliferating, hemangiomas.

DESIGN

All cellular vascular tumors resected from infants younger than 4 months at Arkansas Children's Hospital, Little Rock, over the past 20 years (43 lesions from 36 patients) were first characterized histologically and immunohistochemically, then clinically by chart review.

SETTING

A university-affiliated pediatric hospital.

MAIN OUTCOME MEASURES

Histologic appearance, immunoreactivity for the infantile hemangioma-associated antigens GLUT1 and LeY, and clinical behavior.

RESULTS

Congenital nonprogressive hemangiomas differed from postnatally proliferating infantile hemangiomas in histologic appearance and immunohistochemical profile. Distinguishing pathologic features of these tumors were lobules of capillaries set within densely fibrotic stroma containing hemosiderin deposits; focal lobular thrombosis and sclerosis; frequent association with multiple thin-walled vessels; absence of "intermingling" of the neovasculature with normal tissue elements; and lack of immunoreactivity for GLUT1 and LeY.

CONCLUSION

Congenital nonprogressive hemangiomas are histologically and immunophenotypically distinct from classically presenting hemangiomas of infancy, unlikely to be related to the latter in pathogenesis.

Ley glycolipid-recognizing monoclonal antibody inhibits procoagulant activity and metastasis of human adenocarcinoma

Tumor procoagulant is associated with cancer at advanced stages of malignancy such as infiltration and metastasis. In the present study, we investigated the role of Ley glycolipid in the mechanism of cancer metastasis. Ley glycolipid acts as an important cofactor in the expression of the blood-coagulating activity of cancer cell-derived coagulating activity 1 (CCA-1), which is one of the known tumor procoagulants. Monoclonal antibody (MoAb) FS01, which serves as the Ley-recognizing epitope, inhibits the procoagulant activity of CCA-1 was found to dose-dependently inhibit the procoagulant activity of normal plasma induced by the human lung adenocarcinoma cell line, HAL8, which shows a high level of Ley expression. It did not, however, inhibit the procoagulant activity of the human colon cancer cell line, RPMI4788, which does not express Ley. Administration of FS01 MoAb inhibited lung metastasis of HAL8 cells, but not that of RPMI4788. The absence of antibody-dependent cellular cytotoxicity and complement-mediated cytotoxicity of FS01 MoAb against the HAL8 cell line suggests that the inhibition of HAL8 metastasis by FS01 MoAb derives from the inhibition of blood-coagulating activity of the latter. These findings indicate that Ley glycolipid plays an important role in the mechanism of cancer metastasis via the procoagulant activity of CCA-1.

Selective tumor sensitization to taxanes with the mAb-drug conjugate cBR96-doxorubicin

The chimeric monoclonal antibody cBR96 conjugated to doxorubicin (cBR96-Dox) is selectively internalized by a wide variety of human carcinomas expressing an extended form of Lewis Y antigen (Le(y)). Endocytosis is followed by cleavage and release of free doxorubicin from the endocytic vesicles and subsequent cytotoxicity. Combination studies with standard anti-cancer agents, undertaken to further increase the potency of this targeted therapy, identified significant synergistic anti-tumor activity of cBR96-Dox and either of the taxanes paclitaxel or docetaxel. Treatment with cBR96-Dox 24 hr prior to paclitaxel resulted in a steady increase in the percentage of G(2) tumor cells and corresponding increase in sensitivity to taxanes. Cell cycle analysis indicated the cBR96-delivered doxorubicin was most effective against S-phase cells, yet cells exposed to even subtoxic levels progressed to and arrested in G(2), at a point of high sensitivity to the anti-tubulin agent paclitaxel. The synergy obtained by staged combination of cBR96-Dox and paclitaxel in vitro was reflected in significant anti-tumor efficacy in vivo against xenograft models of human lung and breast tumors that could not be achieved by either agent alone. The staged combination elicited significant or complete regressions of established human Le(y)-positive tumor xenografts using significantly reduced drug levels. Taken together, these data demonstrate a mechanistic approach to the selective elimination of Le(y)-positive tumors by using targeted doxorubicin followed by taxane treatment.