Third party CMV viral specific T-cells for refractory CMV viremia and disease after hematopoietic transplant

BACKGROUND

Refractory CMV viremia and disease are associated with significant morbidity and mortality in recipients of hematopoietic stem cell transplant (HCT).

METHODS

In Phase I/II trials, we treated 67 subjects for CMV viremia or disease arising after allogeneic hematopoietic cell transplant with adoptive transfer of banked off-the-shelf, 3rd party, CMVpp65-sensitized T cells (CMVpp65-VSTs). All were evaluable for toxicity and 59 for response. Evaluable subjects had CMV disease or persisting viremia that had failed at least two weeks of induction therapy with a median of 3 antiviral drugs; 84.7% had >3/11 high risk features. CMVpp65-VSTs were specific for 1-3 CMVpp65 epitopes, presented by a limited set of HLA class I or II alleles, and were selected based on high resolution HLA matching at 2/10 HLA alleles and matching for subject and subject's HCT donor for ≥1 allele through which the CMVpp65-VSTs were restricted.

RESULTS

T-cell infusions were well tolerated. Of 59 subjects evaluable for response, 38 (64%) achieved complete or durable partial responses.

CONCLUSIONS

Recipients responding to CMVpp65VSTs experienced an improved overall survival. Of the risk factors evaluated, transplant type, recipient CD4+ and CD8+ T-cell levels prior to adoptive therapy, and the HLA-restriction of CMVpp65-VSTs infused each significantly affected responses. In addition, CMVpp65-specific T cells of HCT donor or recipient origin contribute to the durability of both complete and partial responses.

TRIAL REGISTRATION

The trials describe were registered with the NIH as follows: NCT00674648, NCT01646645 and NCT02136797. They were single center investigator-initiated trials and were not industry sponsored.

FUNDING

This study was supported by funding from the National Institute of Health (P01 CA23766, R21 CA162002 and P30 CA008748), the Aubrey Fund, Claire Tow Foundation, Major Family Foundation, "Rick" Eisemann Pediatric Research Fund, Banbury Foundation, Edith Robertson Foundation, and Larry Smead Foundation.

Biosorption of Rhodamine B onto novel biosorbents from Kappaphycus alvarezii, Gracilaria salicornia and Gracilaria edulis

In the present investigation seaweeds of macroalgae like Kappaphycus alvarezii, Gracilaria salicornia and Gracilaria edulis used as novel biosorbent in native (KA, GS, GE) and ethanol modified (EKA, EGS, EGE) for Rhodamine B (RB) removal from aqueous solution in batch process. Effect of various biosorption parameters such as pH, initial concentration of RB, biosorbent dosage and contact time were studied. The maximum biosorption capacity determined as 9.84 (KA), 11.03 (GS), 8.96 (GE), 112.35 (EKA), 105.26 (EGS) and 97.08 mg/g (EGE), respectively towards the removal of RB from aqueous solutions. Better removal of RB was observed using EKA, EGS, and EGE biosorbents at 2.0 pH. The characterizations of the biosorbents were performed using Scanning Electron microscope and Fourier Transform Infrared Spectroscopy. Biosorption equilibrium data evaluated using Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Jovanovic isotherm model. The Langmuir isotherm model best suited the equilibrium data for all the biosorbents studied. The rate of RB removal subjected to kinetic analysis using pseudo-first-order, pseudo-second-order, intra-particle diffusion and Elovich models. Pseudo-second-order kinetic model better described the experimental data of the RB biosorption. Desorption studies performed using 0.1 M sodium hydroxide as eluting agents for regeneration and recycle analysis. The recyclability of the six biosorbents showed consistent biosorption capacity towards RB removal up to the entire three cycles. The studied biosorbents sourced from large volume and easily available, further biosorption performance indicated that the KA, GS, GE, EKA, EGS and EGE could be used as efficient, alternative and eco-friendly biosorbents for the removal of harmful dyes in the environment.

Depleting T regulatory cells by targeting intracellular Foxp3 with a TCR mimic antibody

Depletion of T regulatory cells (Tregs) in the tumor microenvironment is a promising cancer immunotherapy strategy. Current approaches for depleting Tregs are limited by lack of specificity and concurrent depletion of anti-tumor effector T cells. The transcription factor forkhead box p3 (Foxp3) plays a central role in the development and function of Tregs and is an ideal target in Tregs, but Foxp3 is an intracellular, undruggable protein to date. We have generated a T cell receptor mimic antibody, "Foxp3-#32," recognizing a Foxp3-derived epitope in the context of HLA-A*02:01. The mAb Foxp3-#32 selectively recognizes CD4 + CD25 + CD127low and Foxp3 + Tregs also expressing HLA-A*02:01 and depletes these cells via antibody-mediated cellular cytotoxicity. Foxp3-#32 mAb depleted Tregs in xenografts of PBMCs from a healthy donor and ascites fluid from a cancer patient. A TCRm mAb targeting intracellular Foxp3 epitope represents an approach to deplete Tregs.

TCR-mimic bispecific antibodies targeting LMP2A show potent activity against EBV malignancies

EBV infection is associated with a number of malignancies of clinical unmet need, including Hodgkin lymphoma, nasopharyngeal carcinoma, gastric cancer, and posttransplant lymphoproliferative disease (PTLD), all of which express the EBV protein latent membrane protein 2A (LMP2A), an antigen that is difficult to target by conventional antibody approaches. To overcome this, we utilized phage display technology and a structure-guided selection strategy to generate human T cell receptor-like (TCR-like) monoclonal antibodies with exquisite specificity for the LMP2A-derived nonamer peptide, C426LGGLLTMV434 (CLG), as presented on HLA-A*02:01. Our lead construct, clone 38, closely mimics the native binding mode of a TCR, recognizing residues at position P3-P8 of the CLG peptide. To enhance antitumor potency, we constructed dimeric T cell engaging bispecific antibodies (DiBsAb) of clone 38 and an affinity-matured version clone 38-2. Both DiBsAb showed potent antitumor properties in vitro and in immunodeficient mice implanted with EBV transformed B lymphoblastoid cell lines and human T cell effectors. Clone 38 DiBsAb showed a stronger safety profile compared with its affinity-matured variant, with no activity against EBV- tumor cell lines and a panel of normal tissues, and was less cross-reactive against HLA-A*02:01 cells pulsed with a panel of CLG-like peptides predicted from a proteomic analysis. Clone 38 was also shown to recognize the CLG peptide on other HLA-A*02 suballeles, including HLA-A*02:02, HLA-A*02:04, and HLA-A*02:06, allowing for its potential use in additional populations. Clone 38 DiBsAb is a lead candidate to treat EBV malignancies with one of the strongest safety profiles documented for TCR-like mAbs.

Abstract 4978: Adoptively transferred CMV-specific T-cells recognizing dominant and sub-dominant pp65 epitopes demonstrate improved in vivo inhibition of tumor xenografts in combination with PD-1 inhibition

Adoptive transfer of transplant donor or third party donor derived CMV-specific T cells (CMV-CTL) can effectively treat CMV infections in HSCT recipients. In clinical trials, infusion of partially matched third party CMV-CTLs, has demonstrated high response rates against persistent CMV infection. T-cells (TC) generated in vitro or directly selected in vivo demonstrate a striking preponderance of specificity for 1-2 immunodominant (ID) epitopes presented by specific HLA alleles. ID epitopes elicit higher TC functional activity in vivo, compared to sub-dominant (SD) epitopes. The relative clinical efficacy of TC directed against ID versus SD epitopes in vivo remains undefined. Agents augmenting activity of TC responsive to SD epitopes are unexplored. When these alleles are co-inherited in humans, epitopes of CMVpp65 presented by HLA A*02:01 are ID over HLA A*24:02 presented epitopes. We describe an in vivo model to assess efficacy of CMV-CTLs using colon carcinoma cells (coca)transduced to express CMVpp65, as a surrogate system. HLA A*02:01 + and A*24:02 + human coca cells were transduced to express CMVpp65 and GFP-firefly luciferase (cocapp65). CMV-CTLs responding to either the A*0201 presented ID NLV epitope (A2-NLV) or the A*24:02 presented SD QYD epitope (A24-QYD) were generated from donors co-inheriting HLA A*02:01 and A*24:02 by in vitro stimulation using NIH 3T3 artificial antigen presenting cells, expressing HLA A*02:01 or A*24:02, B7.1, LFA-3, and ICAM1. Tumor cells (105 cells) were injected subcutaneously into groups of 5-6 NSG mice on the R flank, and 105 cells from a pp65 expressing melanoma cell line (melpp65), lacking expression of HLA A*02:01 or A*24:02 were injected on the L shoulder as control. 2 Groups each received 106 of tetramer+ A2-NLV or A24-QYD CMV-CTLs i.v per mouse; one of each CMV-CTL treated group also received 2 i.v doses ( 200µg /dose) of anti-PD1 antibody (Nivolumab-BMS) at day 2 and 7 post CTL infusion. Control groups received IL-2, with or without anti-PD1, or HLA mismatched CMV-CTLs. Tumor growth was monitored by bioluminescent imaging. CMV-CTLs responsive to SD A24-QYD epitope induced significant cocapp65 growth suppression compared to controls, but did not eradicate tumors in any animal. Combined treatment of A24-QYD CMV-CTLs with anti-PD-1 Ab induced complete cocapp65 eradication in 2 of 5 mice, with minute residual tumors in 3 mice. Treatment with ID A2-NLV CMV-CTLs induced complete cocapp65 eradication in 2 of 5 mice, and smaller residual tumors compared to SD A24-QYD CTL treatment. Combined treatment with anti-PD-1 and A2-NLV CMV-CTLs led to complete cocapp65 eradication in 3 of 5 mice, with minute tumors in 2 mice. Taken together, these data provide evidence that blocking the PD-1/PD-L1 interaction may significantly augment the antiviral activity of both ID and SD CMV-CTLs.

Citation Format: Aisha N. Hasan, Annamalai Selvakumar, Tzu-Yun Kuo, Richard J. O'Reilly. Adoptively transferred CMV-specific T-cells recognizing dominant and sub-dominant pp65 epitopes demonstrate improved in vivo inhibition of tumor xenografts in combination with PD-1 inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4978. doi:10.1158/1538-7445.AM2017-4978

Soluble and membrane-bound interleukin (IL)-15 Rα/IL-15 complexes mediate proliferation of high-avidity central memory CD8+ T cells for adoptive immunotherapy of cancer and infections

The lack of persistence of infused T cells is a principal limitation of adoptive immunotherapy in man. Interleukin (IL)-15 can sustain memory T cell expansion when presented in complex with IL-15Rα (15Rα/15). We developed a novel in-vitro system for generation of stable 15Rα/15 complexes. Immunologically quantifiable amounts of IL-15 were obtained when both IL-15Rα and IL-15 genes were co-transduced in NIH 3T3 fibroblast-based artificial antigen-presenting cells expressing human leucocyte antigen (HLA) A:0201, β₂ microglobulin, CD80, CD58 and CD54 [A2-artificial antigen presenting cell (AAPC)] and a murine pro-B cell line (Baf-3) (A2-AAPC^15Rα/15 and Baf-3^15Rα/15 ). Transduction of cells with IL-15 alone resulted in only transient expression of IL-15, with minimal amounts of immunologically detectable IL-15. In comparison, cells transduced with IL-15Rα alone (A2-AAPC^Rα ) demonstrated stable expression of IL-15Rα; however, when loaded with soluble IL-15 (sIL-15), these cells sequestered 15Rα/15 intracellularly and also demonstrated minimal amounts of IL-15. Human T cells stimulated in vitro against a viral antigen (CMVpp65) in the presence of 15Rα/15 generated superior yields of high-avidity CMVpp65 epitope-specific T cells [cytomegalovirus-cytotoxic T lymphocytes (CMV-CTLs)] responding to ≤ 10^{- 13} M peptide concentrations, and lysing targets cells at lower effector : target ratios (1 : 10 and 1 : 100), where sIL-15, sIL-2 or sIL-7 CMV-CTLs demonstrated minimal or no activity. Both soluble and surface presented 15Rα/15, but not sIL-15, sustained in-vitro expansion of CD62L⁺ and CCR7⁺ central memory phenotype CMV-CTLs (T_CM ). 15Rα/15 complexes represent a potent adjuvant for augmenting the efficacy of adoptive immunotherapy. Such cell-bound or soluble 15Rα/15 complexes could be developed for use in combination immunotherapy approaches.

Biomolecule-assisted solvothermal synthesis of Cu2SnS3 flowers/RGO nanocomposites and their visible-light-driven photocatalytic activities

Elimination of organic pollutants from wastewaters under visible-light irradiation is a venerable challenge in the fields of environmental and material science.

Artificial Antigen Presenting Cells: An Off the Shelf Approach for Generation of Desirable T-Cell Populations for Broad Application of Adoptive Immunotherapy

Adoptive transfer of antigen specific T-cells can lead to eradication of cancer and viral infections. The broad application of this approach has further been hampered by the limited availability of adequate numbers of T-cells for treatment in a timely manner. This has led to efforts for the development of efficient methods to generate large numbers of T-cells with specificity for tumor or viral antigens that can be harnessed for use in cancer therapy. Recent studies have demonstrated that during encounter with tumor antigen, the signals delivered to T-cells by professional antigen-presenting cells can affect T-cell programming and their subsequent therapeutic efficacy. This has stimulated efforts to develop artificial antigen-presenting cells that allow optimal control over the signals provided to T-cells. In this review, we will discuss the cellular artificial antigen-presenting cell systems and their use in T-cell adoptive immunotherapy for cancer and infections.

NK cell tolerance of self-specific activating receptor KIR2DS1 in individuals with cognate HLA-C2 ligand

NK cells are regulated by inhibiting and activating cell surface receptors. Most inhibitory receptors recognize MHC class I Ags and protect healthy cells from NK cell-mediated autoaggression. However, certain activating receptors, including the human activating killer cell Ig-like receptor (KIR) 2DS1, also recognize MHC class I. This fact raises the question of how NK cells expressing such activating receptors are tolerized to host tissues. We investigated whether the presence of HLA-C2, the cognate ligand for 2DS1, induces tolerance in 2DS1-expressing NK cells. Anti-HLA-C2 activity could be detected in vitro in some 2DS1 positive NK clones irrespective of the presence or absence of HLA-C2 ligand in the donor. The frequency of anti-HLA-C2 reactivity was high in donors homozygous for HLA-C1. Surprisingly, no significant difference was seen in the frequency of anti-HLA-C2 cytotoxicity in donors heterozygous for HLA-C2 and donors without HLA-C2 ligand. However, donors homozygous for HLA-C2, compared with all other donors, had significantly reduced frequency of anti-HLA-C2 reactive clones. The 2DS1 positive clones that express inhibitory KIR for self-HLA class I were commonly noncytotoxic, and anti-HLA-C2 cytotoxicity was nearly exclusively restricted to 2DS1 single positive clones lacking inhibitory KIR. 2DS1 single positive NK clones with anti-HLA-C2 reactivity were also present posttransplantation in HLA-C2 positive recipients of hematopoietic stem cell transplants from 2DS1 positive donors. These results demonstrate that many NK cells with anti-HLA-C2 reactivity are present in HLA-C1 homozygous and heterozygous donors with 2DS1. In contrast, 2DS1 positive clones from HLA-C2 homozygous donors are frequently tolerant to HLA-C2.

Nuclear role of WASp in the pathogenesis of dysregulated TH1 immunity in human Wiskott-Aldrich syndrome

The clinical symptomatology in the X-linked Wiskott-Aldrich syndrome (WAS), a combined immunodeficiency and autoimmune disease resulting from WAS protein (WASp) deficiency, reflects the underlying coexistence of an impaired T helper 1 (TH1) immunity alongside intact TH2 immunity. This suggests a role for WASp in patterning T(H) subtype immunity, yet the molecular basis for the TH1-TH2 imbalance in human WAS is unknown. We have discovered a nuclear role for WASp in the transcriptional regulation of the TH1 regulator gene TBX21 at the chromatin level. In primary TH1-differentiating cells, a fraction of WASp is found in the nucleus, where it is recruited to the proximal promoter locus of the TBX21 gene, but not to the core promoter of GATA3 (a TH2 regulator gene) or RORc (a TH17 regulator gene). Genome-wide mapping demonstrates association of WASp in vivo with the gene-regulatory network that orchestrates TH1 cell fate choice in the human TH cell genome. Functionally, nuclear WASp associates with H3K4 trimethyltransferase [RBBP5 (retinoblastoma-binding protein 5)] and H3K9/H3K36 tridemethylase [JMJD2A (Jumonji domain-containing protein 2A)] proteins, and their enzymatic activity in vitro and in vivo is required for achieving transcription-permissive chromatin dynamics at the TBX21 proximal promoter in primary differentiating TH1 cells. During TH1 differentiation, the loss of WASp accompanies decreased enrichment of RBBP5 and, in a subset of WAS patients, also of filamentous actin at the TBX21 proximal promoter locus. Accordingly, human WASp-deficient TH cells, from natural mutation or RNA interference-mediated depletion, demonstrate repressed TBX21 promoter dynamics when driven under TH1-differentiating conditions. These chromatin derangements accompany deficient T-BET messenger RNA and protein expression and impaired TH1 function, defects that are ameliorated by reintroducing WASp. Our findings reveal a previously unappreciated role of WASp in the epigenetic control of T-BET transcription and provide a new mechanism for the pathogenesis of WAS by linking aberrant histone methylation at the TBX21 promoter to dysregulated adaptive immunity.

KIR2DS1 positive Natural Killer cells from individuals expressing cognate HLA ligand are tolerant. (89.58)

Inhibitory KIR-HLA interactions are critical for NK tolerance to self. KIR2DS1 is the only activating counterpart of inhibitory KIRs to have ligand specificity for HLA class I, recognizing HLA-C group 2. Since KIR and HLA genes segregate independently, individuals that carry KIR2DS1 may have HLA-C antigens of the HLA-KIR ligand group C2. We here report that 2DS1 positive NK cells from such individuals are tolerant to such self HLA antigens. We demonstrate that the mechanism for tolerance is different for individuals homozygous or heterozygous for the HLA ligand. NK clones have been generated from KIR2DS1-positive and HLA-C2 homozygous, HLA-C1/C2 heterozygous or HLA-C1 homozygous individuals. Their response against HLA-KIR ligand group C2-expressing targets and their KIR repertoire have been assessed. NK clones expressing KIR2DS1 display anti-HLA-C2 alloreactivity but are tolerant to HLA-C2 if this is a self antigen. This hyporesponsiveness to C2 in C2/C2 homozygous donors is also observed for NK clones lacking 2DL1. In turn, the co-expression of inhibitory KIRs with ligand specificity for self HLA class I including C2 is an important mechanism for tolerance in HLA-C1/C2 heterozygous individuals. This is the first demonstration of activating NK receptor tolerance to cognate self MHC ligand. NK clones expressing only the activating receptor and not the homologous inhibitory receptor are readily identified. Remarkably, NK clones with self HLA ligand specificity are not deleted.

Artificial antigen presenting cells that express prevalent HLA alleles: A step towards the broad application of antigen-specific adoptive cell therapies

The artificial antigen-presenting cells (AAPCs) described in this review were generated to facilitate the production of virus-specific T-cells for the treatment of infections in patients after bone marrow transplant. These AAPCs consist of murine 3T3 cells genetically modified to express critical human molecules needed for T-cell stimulation, such as the co-stimulatory molecules B7.1, ICAM-1, and LFA-3 and one of a series of 6 common HLA class I alleles. When T-cells were sensitized against cytomegalovirus (CMV) using AAPCs that express a shared HLA allele or using autologous antigen-presenting cells (APCs) loaded with the CMVpp65 antigen, they were activated and expanded to become HLA-restricted CMVpp65-specific T-cells. These T-cells demonstrated functional activity in vitro against CMV by producing IFN-gamma and inducing CMVpp65-specific cytotoxicity. T-cells sensitized with AAPCs recognized antigenic epitopes presented by each HLA allele known to be immunogenic in Man. Sensitization with AAPCs also permitted expansion of IFN-gamma+ cytotoxic T-cells against subdominant epitopes that were not effectively recognized by T-cells sensitized with autologous APCs. This panel of AAPCs provides a source of immediately accessible, standardizable, and replenishable "off the shelf" cellular reagents with the potential to make adoptive immunotherapy widely available for the treatment of lethal infections, cancer, and autoimmune diseases.

A panel of artificial APCs expressing prevalent HLA alleles permits generation of cytotoxic T cells specific for both dominant and subdominant viral epitopes for adoptive therapy

Adoptive transfer of virus-specific T cells can treat infections complicating allogeneic hematopoietic cell transplants. However, autologous APCs are often limited in supply. In this study, we describe a panel of artificial APCs (AAPCs) consisting of murine 3T3 cells transduced to express human B7.1, ICAM-1, and LFA-3 that each stably express one of a series of six common HLA class I alleles. In comparative analyses, T cells sensitized with AAPCs expressing a shared HLA allele or autologous APCs loaded with a pool of 15-mer spanning the sequence of CMVpp65 produced similar yields of HLA-restricted CMVpp65-specific T cells; significantly higher yields could be achieved by sensitization with AAPCs transduced to express the CMVpp65 protein. T cells generated were CD8(+), IFN-gamma(+), and exhibited HLA-restricted CMVpp65-specific cytotoxicity. T cells sensitized with either peptide-loaded or transduced AAPCs recognized epitopes presented by each HLA allele known to be immunogenic in humans. Sensitization with AAPCs also permitted expansion of IFN-gamma(+) cytotoxic effector cells against subdominant epitopes that were either absent or in low frequencies in T cells sensitized with autologous APCs. This replenishable panel of AAPCs can be used for immediate sensitization and expansion of virus-specific T cells of desired HLA restriction for adoptive immunotherapy. It may be of particular value for recipients of transplants from HLA-disparate donors.

Knowledge, beliefs, and health care practices relating to treatment of HIV in Vellore, India

In India, little is known about health care-seeking behavior among HIV-infected individuals. Similarly, little is known about how HIV is being treated in the community, in particular by Indian Systems of Medicine (ISM) providers. Therefore, while ART implementation programs continue to expand, it is important to determine whether the knowledge, attitudes, and treatment practices of HIV-infected individuals and their health care providers are aligned with current treatment recommendations. We conducted in-depth qualitative interviews with persons with HIV (n = 9 men and 17 women), family members of persons with HIV (n = 14 men and 3 women), and ISM providers (n = 7). Many of the patients we studied turned at some point to ISM providers because they believed that such practitioners offer a cure for HIV. ISM treatments sometimes had negative impacts including side effects, unchecked progression of an underlying illness, and financial depletion. Indian women tended to be less knowledgeable about HIV and HIV treatments, and had less access to financial and other resources, than men. Finally, most of the ISM providers reported dangerous misconceptions about HIV transmission, diagnosis, and treatment. While the existence of ART in India is potentially of great benefit to those with HIV infection, this study shows that a variety of social, cultural and governmental barriers may interfere with the effective use of these therapies. Partnerships between the allopathic and traditional/complementary health sectors in research, policy, and practice are essential in building comprehensive HIV/AIDS treatment strategies.

KIR2DS1-positive NK cells mediate alloresponse against the C2 HLA-KIR ligand group in vitro

The inhibitory 2DL1 and activating 2DS1 killer Ig-like receptors (KIR) both have shared ligand specificity for codon sequences in the C2 group HLA-Cw Ags. In this study, we have investigated NK cell activation by allogeneic target cells expressing different combinations of the HLA-KIR ligand groups C1, C2, and Bw4. We demonstrate that fresh NK cells as well as IL-2-propagated NK cells from 2DS1-positive donors that are homozygous for the C1 ligand group are activated in vitro by B lymphoblastoid cell lines expressing the C2 group. This response is, in part, due to the absence of C1 group recognition mediated by the inhibitory receptor 2DL2/3. This "missing self" alloresponse to C2, however, is rarely observed in NK cells from donors lacking 2DS1. Even in presence of 2DS1, the NK alloresponse is dramatically reduced in donors that have C2 group as "self." Analysis of selected NK clones that express 2DS1 mRNA and lack mRNA for 2DL1 demonstrates that activation by the C2 ligand and mAb cross-linking of 2DS1 in these clones induces IFN-gamma. Furthermore, this C2 group-induced activation is inhibited by Abs to both HLA class I and the receptor. Collectively, these studies demonstrate that NK cells from 2DS1-positive donors are activated by target cells that express the C2 group as an alloantigen. This leads to increased IFN-gamma-positive fresh NK cells and induces NK allocytotoxicity in IL2-propagated polyclonal NK cells and NK clones. This study also provides support for the concept that incompatibility for the HLA-KIR ligand groups C1, C2, and Bw4 dominates NK alloactivation in vitro.

A High Degree of HLA Disparity Arises From Limited Allelic Diversity: Analysis of 1775 Unrelated Bone Marrow Transplant Donor-Recipient Pairs

The allelic diversity and associated human leukocyte antigen (HLA) disparity of 1775 bone marrow recipients and their unrelated donors, matched for six of six (1361/1775,77%), five of six (397/1775, 22%), or four of six (17/1775, 1%) HLA-A, -B, -DR antigens, were retrospectively evaluated. The comprehensive HLA analysis included the class I (A, B, C) and II (DRB1, DQA1, DQB1, DPA1, DPB1) loci. Most (>66%) of the predominantly Caucasian study population carried one or two of five to seven common alleles at each HLA locus. In spite of this limited diversity, 29% of the six of six antigen-matched transplants carried allele mismatches at HLA-A, -B, and/or -DRB1, and 92% carried at least one allele mismatch at one of the eight HLA loci tested. Of the 968 HLA-A,-B,-DRB1 allele-matched pairs, 89% carried mismatches at other HLA loci, predominantly at DP loci. The substantially greater than expected HLA allelic disparity between donor and recipient suggests extensive haplotypic diversity and underscores the importance of enhancing approaches to mitigate the deleterious effect of HLA mismatches.

Vaccine-induced CD4+ T cell responses to MAGE-3 protein in lung cancer patients

MAGE-3 is the most commonly expressed cancer testis Ag and thus represents a prime target for cancer vaccines, despite infrequent natural occurrence of MAGE-3-specific immune responses in vivo. We report in this study the successful induction of Ab, CD8(+), and CD4(+) T cells in nonsmall cell lung cancer patients vaccinated with MAGE-3 recombinant protein. Two cohorts were analyzed: one receiving MAGE-3 protein alone, and one receiving MAGE-3 protein with adjuvant AS02B. Of nine patients in the first cohort, three developed marginal Ab titers and another one had a CD8(+) T cell response to HLA-A2-restricted peptide MAGE-3 271-279. In contrast, of eight patients from the second cohort vaccinated with MAGE-3 protein and adjuvant, seven developed high-titered Abs to MAGE-3, and four had a strong concomitant CD4(+) T cell response to HLA-DP4-restricted peptide 243-258. One patient simultaneously developed CD8(+) T cells to HLA-A1-restricted peptide 168-176. The novel monitoring methodology used in this MAGE-3 study establishes that protein vaccination induces clear CD4(+) T cell responses that correlate with Ab production. This development provides the framework for further evaluating integrated immune responses in vaccine settings and for optimizing these responses for clinical benefit.

Survey of naturally occurring CD4+ T cell responses against NY-ESO-1 in cancer patients: correlation with antibody responses

NY-ESO-1 is one of the most immunogenic proteins described in human cancers, based on its capacity to elicit simultaneous antibody and CD8+ T cell responses in vivo. Although HLA class II restricted epitopes from NY-ESO-1 have been identified, no broad survey has yet established the status of natural CD4+ T cell responses in cancer patients in relation to CD8+ and antibody responses. We used a recently developed general strategy for monitoring CD4+ responses that overcomes the need for prior knowledge of epitope or HLA restriction to analyze a series of 31 cancer patients and healthy donors for the presence of CD4+ T cells to NY-ESO-1, and related this response to NY-ESO-1 expression in tumor cells and serum antibodies to NY-ESO-1. None of the 18 patients that tested seronegative for NY-ESO-1 had detectable CD4+ T cell responses. On the contrary, 11 of 13 cancer patients with serum antibodies to NY-ESO-1 had polyclonal CD4+ T cell responses directed against various known and previously undescribed NY-ESO-1 epitopes. NY-ESO-1 peptide 80-109 was the most immunogenic, with 10 of 11 patients responding to this peptide. We show here that 12-mer determinants from NY-ESO-1 eliciting a CD4+ T cell response were peptide 87-98 with promiscuous HLA class II presentation, peptide 108-119 restricted by HLA-DP4, and peptides 121-132 and 145-156, both shorter epitopes from previously described HLA-DR4 peptides, also presented by HLA-DR7. This study represents the next step in compiling a comprehensive picture of the adaptive immune response to NY-ESO-1, and provides a general strategy for analyzing the CD4+ T cell response to other tumor antigens eliciting a humoral immune response.

Killer Ig-like receptor haplotype analysis by gene content: evidence for genomic diversity with a minimum of six basic framework haplotypes, each with multiple subsets

Killer Ig-like receptor (KIR) genes constitute a multigene family whose genomic diversity is achieved through differences in gene content and allelic polymorphism. KIR haplotypes containing a single activating KIR gene (A-haplotypes), and KIR haplotypes with multiple activating receptor genes (B-haplotypes) have been described. We report the evaluation of KIR gene content in extended families, sibling pairs, and an unrelated Caucasian panel through identification of the presence or absence of 14 KIR genes and 2 pseudogenes. Haplotype definition included subtyping for the expressed and nonexpressed KIR2DL5 variants, for two alleles of pseudogene 3DP1, and for two alleles of 2DS4, including a novel 2DS4 allele, KIR1D. KIR1D appears functionally homologous to the rhesus monkey KIR1D and likely arose as a consequence of a 22 nucleotide deletion in the coding sequence of 2DS4, leading to disruption of Ig-domain 2D and a premature termination codon following the first amino acid in the putative transmembrane domain. Our investigations identified 11 haplotypes within 12 families. From 49 sibling pairs and 17 consanguineous DNA samples, an additional 12 haplotypes were predicted. Our studies support a model for KIR haplotype diversity based on six basic gene compositions. We suggest that the centromeric half of the KIR genomic region is comprised of three major combinations, while the telomeric half can assume a short form with either 2DS4 or KIR1D or a long form with multiple combinations of several stimulatory KIR genes. Additional rare haplotypes can be identified, and may have arisen by gene duplication, intergenic recombination, or deletions.

Molecular characterization of the HLA-Cw*0409N allele

Various molecular methods in conjunction with serologic assays are used for clinical human leukocyte antigen (HLA) typing. Although serologic reagents detect most HLA-A and -B allospecificities, serologic HLA-C typing is hampered by the lack of informative antisera for many of the known HLA-C gene products. HLA antigens not detected by serology, but detected by molecular methods, are often referred to as "blank" antigens. Their lack of reactivity with antibodies in serological assays often reflects the presence of null alleles. The present study has characterized an HLA-Cw*04 allele (Cw*0409N) detected by DNA typing but not by serology. In cultured B-lymphoid 13W09501 cells carrying this Cw*04 null allele, isoelectric focusing analysis could not detect any component with a pattern compatible with that of the product of the HLA-Cw*0401 allele, but detected components reacting with an anti-HLA-Cw4 and Cw6 monoclonal antibody. Sequencing analysis of the full length HLA-Cw4 cDNA amplified from the cell line 13W095-01 revealed a base deletion at codon 365 in exon 7, resulting in a reading frame shift that added 32 amino acids at the C-terminal of the HLA-Cw4 heavy chain. These results indicate that the HLA-Cw*0409N allele may produce a putative long HLA-Cw4 heavy chain that is not expressed on the cell surface.

Multiple transcripts of the killer cell immunoglobulin-like receptor family, KIR3DL1 (NKB1), are expressed by natural killer cells of a single individual

Natural killer (NK) cells express receptors that are ligands for HLA class I molecules. One family of such NK receptors are called killer cell immunoglobulin-like receptors (KIR). The KIR2DL (inhibiting) and KIR2DS (activating) molecules recognize HLA-Cw antigens, while the KIR3DL (inhibiting) and KIR3DS (activating) molecules interact with HLA-B antigens with the Bw4 epitope. No NK receptors have yet been identified for HLA-B antigens with the Bw6 epitope. We here report four novel full length cDNA transcripts encoding KIR3DL1-like proteins isolated from mRNA obtained from interleukin-2-activated peripheral blood mononuclear cells of a donor with two HLA-B antigens expressing the Bw6 epitope. These four transcripts belong to a group of closely related KIR3DL1-like molecules initially defined by the cDNA clone NKB1. They differ from NKB1 by only 2 to 7 nucleotides and have 2 to 4 codon changes within the 423 residues of the mature protein. All transcripts were detected by RT-PCR, together with the previously reported KIR3DL1 transcripts, NKB1 and KIR3DL1v, in mRNA from NK cells of 10 of 10 donors tested, and in seven of eight NK clones derived from one donor. Functionally, the KIR3DL1 receptors expressed by five DX9-positive NK clones were not inhibiting NK-mediated cytotoxicity when tested against the 721.221 B-lymphoblastoid cell line expressing a HLA-B antigen with Bw4 epitope. All NK clones were, however, inhibited by 721.221 cells transfected with a HLA-B antigen carrying the Bw6 epitope.

LCK-phosphorylated human killer cell-inhibitory receptors recruit and activate phosphatidylinositol 3-kinase

HLA-specific killer cell inhibitory receptors (KIR) are thought to impede natural killer (NK) and T cell activation programs through recruitment of the SH2 domain-containing tyrosine phosphatases, SHP-1 and SHP-2, to their cytoplasmic tails (CYT). To identify other SH2 domain-containing proteins that bind KIR CYT, we used the recently described yeast two-bait interaction trap and a modified version of this system, both of which permit tyrosine phosphorylation of bait proteins. Using these systems, we show that KIR CYT, once phosphorylated by the src-family tyrosine kinase LCK, additionally bind the p85alpha regulatory subunit of phosphatidylinositol (PI) 3-kinase. Furthermore, we show that in an NK cell line, NK3.3, cross-linking of KIR results in recruitment of p85alpha to KIR and activation of PI 3-kinase lipid kinase activity. One consequence of KIR coupling to PI 3-kinase is downstream activation of the antiapoptotic protein kinase AKT. Therefore, in addition to providing negative signals, KIR may also contribute positive signals for NK and T cell growth and/or survival.

Nucleotide and amino acid sequence alignment for human killer cell inhibitory receptors (KIR), 1998

We present alignments of nucleotide sequences and deduced amino acid sequences for all currently identified killer cell inhibitory receptors (KIR). The genes for these receptors have been localized to human chromosome 19q13.4 and constitute a large gene family. They all encode structures typical of type I transmembrane molecules belonging to the immunoglobulin superfamily (Ig-SF). Extensive polymorphism exists within the genes and many of the currently identified cDNA clones represent alternatively spliced forms of previously reported full-length clones. The sequence alignments have been posted on the World Wide Web and are accessible at the Tissue Antigens web site at: http://www.tissue-antigens.dk/kir-align.html. The alignments will be updated at intervals.

Error rate for HLA-B antigen assignment by serology: implications for proficiency testing and utilization of DNA-based typing methods

Until recently, the majority of HLA class I typing has been performed by serology. Expensive commercial typing trays are frequently used for testing non-Caucasian subjects and new strategies using DNA-based methods have been adopted for improving clinical histocompatibility testing results and adapted as supplements in proficiency testing. A double-blind comparison of the typing of HLA-B specificities in 40 samples was carried out between serology and two polymerase chain reaction (PCR) methods, PCR amplification with sequence-specific primers (PCR-SSP) and PCR amplification and subsequent hybridization with sequence-specific oligonucleotide probes (PCR-SSOP). The results demonstrated 22.5% misassignments of HLA-B antigens by serology. There was complete concordance between the results obtained with the two PCR based typing methods. A second panel of 20 donor samples with incomplete or ambiguous serologic results was analyzed by PCR-SSP and SSOP Both PCR methods identified correctly the HLA-B antigens. Our results suggest that more accurate typing results can be achieved by complementing serologic testing with DNA-based typing techniques. The level of resolution for HLA-B antigen assignment can be obtained by this combination of serology and limited DNA-based typing is equivalent to the HLA-B specificities defined by the WHO-HLA Committee. This level of resolution cannot routinely be achieved in clinical histocompatibility testing or in proficiency testing using serologic reagents only.

The killer cell inhibitory receptor genomic region on human chromosome 19q13.4

Multiple genes encoding type I transmembrane molecules and belonging to the immunoglobulin superfamily have recently been localized to human chromosome 19q13.4. These include a family of genes encoding killer cell inhibitory receptors (KIR) expressed on natural killer (NK) cells and subsets of T-lymphocytes, immunoglobulin-like transcripts (ILT-1, -2 and 3) expressed on myeloid cells and subsets of lymphoid cells, the gp49 family of receptors expressed on mast cells and NK cells and the gene encoding human myeloid immunoglobulin A Fc receptor (CD89). The receptors have one to four extracellular immunoglobulin domains, and the ligands are known for some of these molecules. This includes the Fc alpha R and KIRs of the p58/p50 and p70/p70 delta, but the ligands for many others are unknown. Except for CD89, each subfamily of receptors exist, in two forms, of which one has a long cytoplasmic domain containing one to four immunoreceptor tyrosine-based inhibitory motifs (ITIM) and another form with a short cytoplasmic tail without ITIMs. ITIM-containing receptors can recruit cytoplasmic tyrosine phosphatases and provide inhibitory signals for cell activation, whereas receptors with a "short" tail induce activating signals. The 19q13.4 chromosomal region is therefore now emerging as the immunoglobulin superfamily linkage group of genes differentially expressed on hematopoietic cell lineages and encoding pairs of receptors with opposing effects on signal transduction pathways and effector functions in hematopoietic cells.

Genomic organization and allelic polymorphism of the human killer cell inhibitory receptor gene KIR103

Killer cell inhibitory receptors (KIR) belong to the immunoglobulin superfamily of molecules and are expressed on natural killer (NK) cells. The KIRs of the p58/p50 family have two immunoglobulin domains and are ligands for HLA-Cw antigens, whereas the p70/p70 delta family has three immunoglobulin domains and comprises ligands for HLA-B antigens and possibly some HLA-A antigens. Members of a third KIR family, KIR103, have two immunoglobulin domains but have highest nucleotide sequence homology to the p70 family. The ligands for KIR103 on target cells are currently unknown. We here report the complete genomic organization of KIR103. It spans about 12 kb of DNA and consists of eight exons of which exon 1 and exon 2 encode the leader sequence. Exon 3 encodes the first immunoglobulin domain (gamma 1), and exon 4 encodes the main part of the second immunoglobulin domain (gamma 3), which also contains sequences contributed by exon 5 and exon 6. Exon 6 encodes the transmembrane domain, whereas exons 7 and 8 encode most of the cytoplasmic domain. KIR103 is polymorphic, and two alleles, 103AS and 103LP, are defined in this study. Additional full-length cDNA clones for KIR103 have been isolated and are shown to be formed by alternative mRNA splicing with exon skipping. Some of these truncated KIR103 cDNA could encode shorter transmembrane molecules, whereas others lack the transmembrane domain and are candidate genes for secreted KIR products. KIR103 is localized to the KIR genetic region on chromosome 19q13.4.

Polymorphism and domain variability of human killer cell inhibitory receptors

Thirty-two different full-length cDNA clones for human killer cell inhibitory receptors (KIR) have been identified. They all belong to the immunoglobulin superfamily and encode mature proteins with one, two or three extracellular Ig domains. The inhibitory receptors have nearly identical transmembrane domains and cytoplasmic domains ranging in length from 76 to 95 amino-acid residues. The activating receptors have a characteristic transmembrane domain with a charged lysine residue and a short cytoplasmic tail without the protein tyrosine phosphatase binding motif I/VXYXXL present in the inhibitory receptors. Sequence analysis demonstrates that three clusters correspond to the inhibitory receptors of 58 kDa, while two clusters encode activating receptors of 50 kDa. Two other clusters correspond to the inhibitory receptors of 70 kDa and one cluster encodes genes with sequence homology to one of the two p70 clusters but contains the transmembrane and cytoplasmic domains characteristic of activating receptors. The data are consistent with a genomic organization of the KIR genetic region containing at least three KIR genes encoding receptors for each of the gene products of the HLA class I loci. Alternative mRNA splicing could be responsible for generation of activating or inhibitory receptors with the same extracellular domains. Separate genes encoding receptors with opposite function is, however, an equally likely possibility.

Analysis of CD28 cytoplasmic tail tyrosine residues as regulators and substrates for the protein tyrosine kinases, EMT and LCK

The CD28 cell surface receptor provides an important costimulatory signal for T cells necessary for their response to Ag. Early events in CD28 signaling include recruitment and activation of phosphatidylinositol 3-kinase (PI3-kinase) and activation of the protein tyrosine kinases (PTKs), LCK and EMT. Recruitment and activation of PI3-kinase is known to be dependent upon phosphorylation of tyrosine 173 of the CD28 cytoplasmic tail contained within a YMNM motif. By contrast, little is known of which residues of the CD28 tail, including tyrosines, are required for the activation of PTKs. To address this we studied the ability of truncation mutants and tyrosine to phenylalanine substitution mutants of the CD28 cytoplasmic tail to activate LCK and EMT in Jurkat T leukemia cells. Our results indicate that 1) activation of EMT is partially dependent upon tyrosine 173 of the CD28 tail, although it does not require PI3-kinase activation; 2) activation of LCK is independent of CD28 cytoplasmic tail tyrosine residues; and 3) elements sufficient for the activation of both kinases are contained within the first half of the tail. In addition we studied the CD28 tail as a substrate for both PTKs in in vitro kinase assays. We demonstrate that EMT can phosphorylate all four tyrosines of the CD28 tail, in contrast to LCK, which phosphorylates only tyrosine 173. Together with evidence that in vivo, tyrosines other than tyrosine 173 become phosphorylated following CD28 stimulation, this finding suggests that, like LCK, one function of EMT during CD28 signaling is phosphorylation of the receptor.

Analysis of CD28 cytoplasmic tail tyrosine residues as regulators and substrates for the protein tyrosine kinases, EMT and LCK

The CD28 cell surface receptor provides an important costimulatory signal for T cells necessary for their response to Ag. Early events in CD28 signaling include recruitment and activation of phosphatidylinositol 3-kinase (PI3-kinase) and activation of the protein tyrosine kinases (PTKs), LCK and EMT. Recruitment and activation of PI3-kinase is known to be dependent upon phosphorylation of tyrosine 173 of the CD28 cytoplasmic tail contained within a YMNM motif. By contrast, little is known of which residues of the CD28 tail, including tyrosines, are required for the activation of PTKs. To address this we studied the ability of truncation mutants and tyrosine to phenylalanine substitution mutants of the CD28 cytoplasmic tail to activate LCK and EMT in Jurkat T leukemia cells. Our results indicate that 1) activation of EMT is partially dependent upon tyrosine 173 of the CD28 tail, although it does not require PI3-kinase activation; 2) activation of LCK is independent of CD28 cytoplasmic tail tyrosine residues; and 3) elements sufficient for the activation of both kinases are contained within the first half of the tail. In addition we studied the CD28 tail as a substrate for both PTKs in in vitro kinase assays. We demonstrate that EMT can phosphorylate all four tyrosines of the CD28 tail, in contrast to LCK, which phosphorylates only tyrosine 173. Together with evidence that in vivo, tyrosines other than tyrosine 173 become phosphorylated following CD28 stimulation, this finding suggests that, like LCK, one function of EMT during CD28 signaling is phosphorylation of the receptor.

New HLA-DR haplotypes containing the DRB6 pseudogene

An unexpected probe reaction pattern was observed in two samples during HLA-DR typing by PCR-Sequence Specific Oligonucleotide Probes. In order to confirm the unusual typings, samples were analyzed by PCR-Sequence Specific Primers, cloning, and nucleotide sequencing of the second exon of the HLA-DRB-genes. The confirmed DR, DQ phenotype for one sample was DRB1*0701, DRB4*01, DRB5*0101, DRB6*0201, DQB*0602, DQB1*0202. The phenotype of other sample was DRB1*1602, DRB1*1302, DRB3*0301, DRB6*0101, DQB1*0501, DQB1*0502. The first sample has the novel combination of DRB1*0701 with DRB5*0101 and DRB6*0201. The second sample has either DRB6*0101 together with DRB1*1602 in absence of any DRB5 allele or DRB6*0101 together with DRB1*1302, DRB3*0301. We postulate that the most likely haplotype in sample #1 is DRB1*0701; DRB5*0101, DRB1*0602 which could have arisen from gene conversion. The most likely haplotype in sample #2, DRB1*1602, DRB6*0101, DQB1*0502 would have arisen from an homologous recombination event.

NK cell receptor gene of the KIR family with two IG domains but highest homology to KIR receptors with three IG domains

The killer cell inhibitory receptors (KIRs) are surface glycoproteins expressed by natural killer (NK) cells and some T cells. They recognize polymorphic human HLA class I molecules. Two families of KIRs have been identified and named p58 and p70. The p58 family of genes encode type I membrane proteins with two extracellular immunoglobulin (Ig) domains, while the p70 genes have three Ig domains. We here report the cloning and characterization of a novel KIR cDNA obtained from tumor cell lines with NK reactivity (YT and NK-92). This gene is also expressed in the normal cell line NK 3.3 and in NK cells obtained from some but not all normal donors. The clone, KIR103AS, has an open reading frame consistent with a KIR with two extracellular Ig domains, a transmembrane region and a 114 amino acid long cytoplasmic domain containing a single src homology 2 (SH2) binding motif. The membrane distal Ig domain of KIR103AS has highest homology with the first Ig domain of p70 KIRs and differs significantly from the first Ig domain of p58 KIRs. The second, membrane proximal Ig domain of KIR103AS has similar and high homology with the membrane proximal Ig domains of both p70 and p58 KIRs. The extracellular domains of KIR103AS therefore share characteristic features with both p70 and p58 genes: the domain structure is identical to p58 KIRs but the sequence homology matches closely with p70 KIRs. The putative transmembrane and cytoplasmic domains are distinctly different from all previously reported KIR cDNAs.

Phosphorylation of each of the distal three tyrosines of the CD28 cytoplasmic tail is required for CD28-induced T cell IL-2 secretion

Signaling by the CD28 T cell costimulatory receptor is known to involve recruitment and activation of phosphatidylinositol 3-kinase (PI3-kinase) which is dependent upon phosphorylation of tyrosine 173 of the CD28 cytoplasmic tail, present in a YMNM motif. However, whether this phosphorylation is required for CD28 costimulation and whether or not phosphorylation of any of the other three tyrosines of the CD28 cytoplasmic tail (tyrosines 188, 191 and 200) is also important for CD28 induced responses is unclear. To address this we examined the ability of chimeric receptors, consisting of the extracellular plus transmembrane membrane domain of human CD8 alpha linked to different mutated human CD28 cytoplasmic tails, to induce IL-2 secretion in Jurkat T leukemia cells in the presence of PMA and ionomycin. A receptor in which tyrosine 173 of the CD28 tail was mutated to phenylalanine was able to induce IL-2. By contrast, receptors which contained single tyrosine 188, 191 or 200 to phenylalanine substitutions were unable to induce IL-2. These results imply that in this system phosphorylation of tyrosine 173 and hence activation of PI3-kinase is not required for CD28 induced IL-2 secretion. Further, they imply that phosphorylation of each of tyrosines 188, 191 and 200 is necessary for this response. Despite an apparent requirement for phosphorylation of all three of these tyrosines, however, receptors which contain tyrosine only at positions 191 or 200 and a truncated receptor which does not contain tyrosine 200 induce normal IL-2. These last findings, therefore, illustrate the complexity of CD28 mediated activation signals.

Novel isoforms of murine intercellular adhesion molecule-1 generated by alternative RNA splicing

Intercellular adhesion molecule-1 (ICAM-1)-deficient mice, produced by homologous recombination and previously recognized to be devoid of the common form of ICAM-1, are shown to express residual amounts of ICAM-1 Ag in thymus and lung. We demonstrate that this expression of ICAM-1 is possible because the mutated exon 5 in these animals has been skipped by alternative splicing of RNA. Three different alternative isoforms of ICAM-1 are expressed in mutant mice. Moreover, two of these isoforms are expressed in wild-type mice together with two additional alternative isoforms that cannot be produced in mutant mice. All alternatively spliced isoforms of ICAM-1 detected are missing complete extracellular Ig domains. In both mutant and wild-type mice, expression of alternatively spliced isoforms is up-regulated following stimulation of animals with LPS. Furthermore, all alternative isoforms of ICAM-1, except one, retain the ability to bind to the well-recognized ICAM-1 counter-receptor LFA-1. These findings, along with the restricted tissue distribution in mutant mice, indicate that alternative isoforms of ICAM-1 are significant physiologic adhesion structures which could play a distinct role in the functioning of the immune system of intact animals.

Novel isoforms of murine intercellular adhesion molecule-1 generated by alternative RNA splicing

Intercellular adhesion molecule-1 (ICAM-1)-deficient mice, produced by homologous recombination and previously recognized to be devoid of the common form of ICAM-1, are shown to express residual amounts of ICAM-1 Ag in thymus and lung. We demonstrate that this expression of ICAM-1 is possible because the mutated exon 5 in these animals has been skipped by alternative splicing of RNA. Three different alternative isoforms of ICAM-1 are expressed in mutant mice. Moreover, two of these isoforms are expressed in wild-type mice together with two additional alternative isoforms that cannot be produced in mutant mice. All alternatively spliced isoforms of ICAM-1 detected are missing complete extracellular Ig domains. In both mutant and wild-type mice, expression of alternatively spliced isoforms is up-regulated following stimulation of animals with LPS. Furthermore, all alternative isoforms of ICAM-1, except one, retain the ability to bind to the well-recognized ICAM-1 counter-receptor LFA-1. These findings, along with the restricted tissue distribution in mutant mice, indicate that alternative isoforms of ICAM-1 are significant physiologic adhesion structures which could play a distinct role in the functioning of the immune system of intact animals.

Prothymosin alpha gene in humans: organization of its promoter region and localization to chromosome 2

A genomic clone encoding prothymosin alpha (gene symbol: PTMA), a nuclear-targeted protein associated with cell proliferation, was isolated and the 5'-regulatory region subcloned and sequenced. Because of previously reported discrepancies between several cDNA clones and a genomic clone for prothymosin alpha, we determined the sequence of the first exon and of a 1.7-kb region 5' to the first exon. The sequence of the genomic clone reported here corresponds to the published cDNA sequences, suggesting that the previously noted discrepancies may be due to genetic polymorphism in this region. In addition, our sequence data extend the known 5'-upstream sequence by an additional 1.5 kb allowing the identification of numerous, potential cis-acting regulatory sites. This 5'-flanking cloned probe permitted us to localize the prothymosin gene to chromosome 2 in humans.

Genomic organization and chromosomal location of the human gene encoding the B-lymphocyte activation antigen B7

The human B lymphocyte activation antigen B7 provides regulatory signals for T lymphocytes as a consequence of binding to its ligands CD28 and CTLA-4. The cDNA for B7 has previously been isolated and predicted to encode a type I membrane protein. The predicted polypeptide has a secretory signal peptide followed by two contiguous Ig-like domains, a hydrophobic transmembrane region and a short cytoplasmic tail. Here we report the exon-intron genomic organization of human B7 and the chromosomal location. The gene has six exons that span approximately 32 kilobases of DNA. Exon 1 is not translated and the second exon contains the initiation ATG codon and encodes a predicted signal peptide. This gene structure is characteristic for several eukaryotic genes with tissue-specific expression. The third and fourth exons correspond to two Ig-like domains whereas the fifth and sixth exons encode respectively the trans-membrane portion and the cytoplasmic tail. This close relationship between exons and functional domains is a characteristic feature of genes of the Ig superfamily. Cell surface expression of the B7 gene product has previously been mapped to human chromosome 12 by antibody reactivity with the B7-specific monoclonal antibody BB-1. We here demonstrate that the B7 gene is located to the q21-qter region of chromosome 3 by DNA blot analysis of human x rodent somatic cell hybrids.

Characterization of a novel, human cytotoxic lymphocyte-specific serine protease cDNA clone (CSP-C)

A human cDNA clone encoding a novel serine protease, cytotoxic serine protease-C(CSP-C), has been isolated from a cDNA library prepared from recombinant interleukin-2 (IL-2)-activated lymphocytes of a patient with a large granular lymphoproliferative disorder. The clone has a 741-base pair open reading frame encoding a putative 246-amino acid protein. The protein sequence contains the catalytic charge relay system characteristic of a serine protease and the conserved N-terminal amino acid sequence of the mature cytotoxic lymphocyte serine proteases found in both mouse and human. The amino acid sequence of CSP-C has 71% identity with the previously reported cytotoxic serine protease-B(CSP-B)/human lymphocyte protease (HLP)/SECT and 57% identity with the granulocyte-specific serine protease cathepsin G. The homology with another lymphocyte-specific serine protease, human Hanukah factor (HF)/Granzyme A was 41%. The transcript is expressed in lymphocytes stimulated with IL-2 or IL-2 plus phytohemagglutinin (PHA). CSP-C is not expressed in B-lymphoblastoid cell lines or in the T-leukemia cell line MOLT4. The cDNA sequence suggests that the protein is expressed as a prepropeptide, as has been found in the other murine and human serine proteases of lymphocyte origin. It has recently been reported that human chromosome 14q11, in addition to containing the genes encoding cytotoxic serine protease B (CSP-B), cathepsin G, and the T-cell receptor alpha and delta genes, also includes an additional genomic DNA clone which cross-hybridized with CSP-B and cathepsin G, cathepsin-like gene-2 (CGL-2). It is likely that the CSP-C cDNA clone reported in this study corresponds to CGL-2.

Distribution of HLA antigens in the native South Indian Tamil Hindus

Blood samples from 240 unrelated healthy Tamil-speaking South Indian Hindus residing in Madras (capital city of Tamil Nadu, India) were screened for HLA-A and -B antigen profiles. Antigen, gene and haplotype frequencies were calculated and compared with the literature. Tamil Hindus lack A31, A32, Aw33, B16, B21 and Bw41. However, except for minor differences (low occurrence of Aw19 antigen), the South Indians show similarity to North Indian and other Indian groups. The data confirm once more that the haplotype A1-B17 is characteristic of Indians.

Glyoxalase-I and esterase D polymorphisms in Kotas and Badagas of Nilgiri Hills, south India

Blood samples from 217 unrelated individuals belonging to two endogamous populations, Kotas and Badagas of the Nilgiri Hills, South India, were screened for glyoxalase I and esterase D polymorphisms using mixed starch-agarose gel electrophoresis. The GLO1*1 gene frequency estimates were 0.1887 and 0.1982 for Kotas and Badagas. The ESD*1 gene frequency estimates were 0.7123 and 0.7568 for Kotas and Badagas, respectively. The results are compared with those available for other Indian populations.

Distribution of HLA antigens in Kotas and Badagas of the Nilgiri Hills, South India

Blood samples from 103 Kotas and 58 Badagas residing in the Nilgiri Hills, South India, were examined for HLA-A and -B antigen profiles. The Kota group was characterized by fairly high frequencies of A2 and B7 antigens as well as the haplotype A2-B7. The frequencies of Aw19, A28, and Bw22 were found to be higher in Badagas than in Kotas. The results are compared with the literature available on other Indian populations.