Genomic organization of the human LAG-3/CD4 locus.
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Antigens, CD↗
Biomedical subjects
F Triebel
Publications and source records attributed to F Triebel.
In situ demonstration of renal-cell-carcinoma-specific T-cell clones.
Using mixed lymphocyte tumor-cell culture (MLTC) in a selected renal-cell carcinoma, we derived a tumor-specific T-cell line in which Vbeta14+ and Vbeta19+ T cells represented 70% of the whole T-cell population. Selected Vbeta19+ T cells were CD8+ and exhibited a HLA-restricted specific cytotoxicity against tumor cells. Independently, 2 CTL clones were obtained by direct cloning of tumor-infiltrating lymphocytes, VIIIC2 CTL expressing a Vbeta19 and VIIB10 CTL a Vbeta13 T-cell-receptor transcript. VIIB10 lysed autologous tumor cells, normal kidney cells and EBV-transformed B cells. In contrast, VIIIC2 lysed tumor cells exclusively, demonstrating that the antigen structure recognized is tumor-specific. In addition, we used a PCR-based method to search for the presence of these CTL in situ. TCR beta chain of VIIIC2 and VIIB10 CTL were sequenced and primers complementary to their N regions were synthesized. VIIIC2 CTL constituted up to 60% of Vbeta19 transcripts in MLTC T-cell lines derived from tumor-infiltrating lymphocytes, 23% in tumor and 26% in a tumor-draining lymph node, while VIIB10 was not detected. Thus, VIIIC2 CTL was successfully derived from lymphocytes infiltrating a renal-cell carcinoma by direct cloning as well as by MLTC, probably because it was highly expanded in vivo within the tumor composing almost 2% of the TIL.
Base Sequence↗
Clonal T cell expansion induced by interleukin 2 therapy in blood and tumors.
In a phase I clinical trial on the effects of preoperative adjuvant IL-2 therapy given to patients undergoing hepatic resection of colorectal adenocarcinoma metastases, we monitored the putative induction of T cell clonal expansion in both tissues and blood. The presence of T cell clonotypes was analyzed with a PCR-based method that determines V-D-J junction size patterns in T cell receptor (TCR) V beta subfamilies in samples before and after a 5-d IL-2 infusion. This high resolution method analyzing CDR3 sizes of TCR transcripts was used in conjunction with FACS analysis of the corresponding T cell subpopulations with TCR V beta-specific mAb. At time of surgery (day 8 after starting IL-2), we found in the three patients analyzed with V beta-C beta primers multiple dominant T cell clonotypes in the tumor and peritumoral tissues which had probably expanded as a result of therapy. In three control patients not treated with IL-2, multiple oligoclonal patterns were not observed with this set of primers. In the fourth control patient a unique V beta 21-C beta CDR3 pattern which corresponds to two dominant clonotypes was found in the tumor. The same dominant clonotypes identified in the tumor after IL-2 were also detectable in the blood and comparison of the profiles obtained before and after IL-2 therapy indicates that they were induced by IL-2. The relative expansion of the corresponding T cell subpopulations was maintained for varying periods of time after surgery (4-7 d and almost 2 yr in one case). Together, these results indicate that IL-2 induces marked expansion of several T cell clones. Systemic IL-2 administration may represent, either alone or as a vaccine adjuvant, an appropriate way of boosting antigen-specific immune responses.
Adenocarcinoma↗
T-cell receptor repertoire in neuroblastoma patients.
Spontaneous regression of widespread lesions is a characteristic feature of neuroblastoma. One may postulate that the immune response contributes to these clinical regressions. Accordingly, we studied the T-cell receptor (TCR) repertoire of tumor-infiltrating lymphocytes in eight neuroblastoma tumors. The expression of 29 V alpha and 24 V beta gene segment subfamily specificities was analyzed by PCR and compared by computerized densitometry of Southern blots to values obtained in the blood. Overall, the TCR repertoire of these eight patients was diverse, with virtually all V alpha and V beta specificities expressed. Nonetheless, four of these patients showed V beta 2 gene segment subfamily overexpression in the tumor corresponding to local expansion of polyclonal T-cell subpopulations. In one patient, this expansion could be due to local secretion of superantigenic activity, as suggested by the specific stimulation of murine T cells expressing a human V beta 2 chain by supernatant of the corresponding neuroblastoma cell line. In addition, high-resolution analysis of the TCR beta transcript complementarity-determining region 3 sizes identified three patients (of six studied) with marked clonal T-cell expansion in the tumor not seen in the blood. The specific expression of several dominant clono-types in the tumor may be related to the recognition of neuroblastoma-specific antigens in these patients. Together, these results on the TCR repertoire expressed in vivo may lead to the characterization of putative immune response mechanisms (i.e., antigen- or superantigen-driven stimulation) which participate in tumor regression.
Animals↗
T cell major histocompatibility complex class II molecules down-regulate CD4+ T cell clone responses following LAG-3 binding.
T cell response to its antigen requires recognition by the T cell receptor together with a co-receptor molecule, either CD4 or CD8. Additional molecules have been identified that are capable of delivering the co-stimulatory signals provided by APC. Following T cell priming, a number of T cell activation antigens are expressed that may play a role in the inactivation phase of the T cell response. The lymphocyte activation gene (LAG)-3 protein and its counter-receptors, the major histocompatibility complex (MHC) class II molecules, are such activation antigens whose interaction may result in the down-regulation of the ongoing immune response. To investigate the role of LAG-3/class II molecule interaction, we produced a soluble form of LAG-3 by fusing the extracellular Ig domains of this membrane protein to the constant region of human IgG1 (LAG-3Ig). Here, we show a direct and specific binding of LAG-3Ig to class II molecules on the cell surface. In addition, we show that LAG-3/class II molecule interaction leads to the down-regulation of CD4+ Ag-specific T cell clone proliferation and cytokine secretion. This inhibitory effect is observed at the level of the effector cells and not the APC and is also found with anti-CD3 mAb, PHA + PMA or low-dose IL-2 driven stimulation in the absence of APC. These functional studies indicate that T cell MHC class II molecules down-regulate T cell proliferation following LAG-3 binding and suggest a role for LAG-3 in the control of the CD4+ T cell response.
Antigens, CD↗
Low-dose IL-2 treatment: activation of discrete T- and NK-cell sub-populations in vivo.
The activation of T- and NK-cell sub-populations in vivo was evaluated in a phase-I study (18 patients) with a 3-month course of low-dose s.c. IL-2, 1, 3 and 6 x 10(6) IU/day once daily, 6 days a week. At the higher doses, we observed early on (day 15) an increase in CD3+ CD56-, CD3- CD56+ and CD56+ DR+ cell counts, as well as an increase in circulating sIL-2R and non-MHC-restricted cytotoxicity against K562 and Daudi cells. In contrast, at the lowest dose, T- and NK-cell counts were not appreciably altered, while a substantial increase in NK cytotoxic activity was still observed. In addition, thyroid dysfunction resembling that described in auto-immune thyroiditis, was documented in 6 out of the 14 patients studied. Using a high-resolution method analyzing CDR3 sizes of TCR beta transcripts, we observed the appearance of dominant T-cell clonotypes in 1 patient out of 2 analyzed, corresponding to the clonal expansion of T cells primed in vivo. Overall, these results show that long courses of low-dose s.c. IL-2 treatment lead to the activation of discrete T- and NK-cell sub-populations.
Carcinoma, Renal Cell↗
In vivo local expansion of clonal T cell subpopulations in renal cell carcinoma.
Renal cell carcinoma (RCC) is one human tumor to which the immune response may control the growth of tumor cells. These tumors are infiltrated by a large mononuclear infiltrate mainly composed of T lymphocytes. To characterize the lymphocytes infiltrating RCC, we analyzed the molecular structure of the T cell receptor (TCR) alpha and beta chains in tumor and paired peripheral blood lymphocytes from a series of 6 untreated patients. We first determined V alpha and V beta gene segment usage by PCR using a panel of V specific oligonucleotide primers (V alpha 1-w29 and V beta 1-w24). A highly diverse usage of TCR V alpha and V beta gene usage was observed in 5 of 6 tumors. In addition, the few tumor overexpressed V beta specificities detected by reverse transcription-PCR were shown to contain minor T cell expansions. Strikingly, 1 of the 6 tumor studied displayed a skewed TCR repertoire with V beta 4 transcript representing 25% of the TCR signals. Clonality of the tumor overexpressed V beta transcripts was analyzed by CDR3 size distribution analysis. In the particular tumor displaying a biased repertoire large expansions of T cell subpopulations were detected (particularly in V beta 4) specifically at the tumor site. Such T cells may be expanded locally in response to tumor antigens.
Adult↗
CD4/major histocompatibility complex class II interaction analyzed with CD4- and lymphocyte activation gene-3 (LAG-3)-Ig fusion proteins.
We analyzed CD4 major histocompatibility complex (MHC) class II interactions with CD4 and lymphocyte activation gene (LAG)-3 recombinant fusion proteins termed CD4Ig and LAG-3Ig. CD4Ig bound MHC class II molecules expressed on the cell surface only when used in the micromolar range. This weak CD4Ig binding was specific, since it was inhibited by anti-CD4 and anti-MHC class II mAb. LAG-3Ig bound MHC class II molecules with intermediate avidity (Kd = 60 nM at 37 degrees C). Using LAG-3Ig as a competitor in a CD4/MHC class II-dependent cellular adhesion assay, we showed that this recombinant molecule was able to block CD4/MHC class II interaction. In contrast, no inhibition was observed in a CD4/MHC class II-dependent T cell cytotoxicity assay. Together, these results suggest that co-engagement of the TcR with CD4 alters the CD4/MHC class II molecular interaction to become insensitive to LAG-3Ig competition.
Animals↗
T-cell repertoires in healthy and diseased human tissues analysed by T-cell receptor beta-chain CDR3 size determination: evidence for oligoclonal expansions in tumours and inflammatory diseases.
Many examples of oligoclonal T-cell expansion in infiltrated diseased tissues have been reported. However, it remains to be established whether such observations can be generalized and to what extent oligoclonal patterns obtained after in vitro culture of T-cell infiltrates reflect in vivo situations. Using new high resolution analysis which requires no in vitro cellular expansion, we detected such oligoclonal T-cell expansions in 7/7 melanoma tumour biopsies, 3/3 biopsies of inflammatory skin during acute graft versus host disease (aGVHD) after allogeneic bone marrow transplantation (alloBMT) and 7/7 synovial membranes from patients with rheumatoid arthritis. Thus, oligoclonal T-cell expansions are readily observed when a sufficiently sensitive detection method is used, suggesting that similar expansions are the rule among T-cell infiltrates in different diseases. This observation and the monitoring of the in vivo evolution of such expansion during the course of the disease and during in vitro culture should have important clinical implications.
Acute Disease↗
Phase I study of prolonged low-dose subcutaneous recombinant interleukin-2 (IL-2) in patients with advanced cancer.
The present trial was designed to assess the feasibility of subcutaneous low-dose interleukin-2 (IL-2) given for 3 months in an outpatient setting. Twenty patients with advanced cancers (16 metastatic renal cell carcinoma) were included in this phase I study at the following three dose levels: 1, 3, and 6 x 10(6) IU/day (groups of 6, 6, and 8 patients, respectively). IL-2 was administered once daily 6 days a week for 12 weeks. Complete therapy was achieved in 13 of 20 patients, whereas 5 of 20 received at least 5 weeks of IL-2. Minor dose-dependent toxicities were observed including fatigue, transient grade 2-3 fever (11 of 18), and grade 1-2 digestive disorders (6 of 18) without significant biologic modifications but two cases of hypothyroidism. Doses were decreased from 6 to 3 x 10(6) IU/day in one patient (fever and allergic edema). All patients developed transient subcutaneous nodules at the injection sites. These side effects never required hospitalization nor discontinuation of therapy. A dose-dependent and sustained increase in peripheral blood eosinophils and lymphocytes was observed, demonstrating that subcutaneous injections in this low-dose range could have similar biologic effects to those achieved with more intensive schedules. Because it is safe, practicable, and low in cost, we conclude that s.c. low-dose IL-2 could be useful for the design of immunomodulation trials with potential new application fields.
Adult↗
Phase I-II randomized study on prehepatectomy recombinant interleukin-2 immunotherapy in patients with metastatic carcinoma of the colon and rectum.
BACKGROUND: This study, which investigates prehepatectomy immunostimulation with recombinant interleukin-2 (rIL-2), had two goals: to evaluate the tolerance of rIL-2 in association with major hepatectomy, and to verify whether preoperative immunostimulation is effective (neoadjuvant immunotherapy). In animal experiments, the conjunction of shed tumor cells into the circulation during surgery and severe surgery-induced immunodepression can promote the dissemination of the disease. Perioperative immunostimulation by rIL-2 reduces the incidence of metastases in animals. STUDY DESIGN: This prospective phase I-II randomized study included 19 patients with potentially resectable hepatic metastases from adenocarcinomas of the colon and rectum. Two-thirds were randomized to the rIL-2-treated group and one-third to the control group. Preoperative rIL-2 was administered by continuous intravenous infusion over five days and stopped two days before major hepatectomy. The dose of rIL-2 was gradually increased, from 3 x 10(6) IU/m2/day to 12 x 10(6) IU/m2/day. At least three patients were studied at each dose level before increasing the rIL-2 dose. Nineteen patients were eligible for the study (12 in the rIL-2 group and seven in the control group). Toxicity during infusion and intraoperative and postoperative complications were evaluated. Immunological monitoring consisted of repeated determination of lymphocyte counts and phenotypic analysis of lymphocyte subpopulations. Non-major histocompatibility complex-restricted cytotoxicity was assayed against K562 and DAUDI tumor cell lines. RESULTS: Toxicity during rIL-2 infusion was acceptable, similar to that of other phase I studies, and surgery was never delayed. Morbidity and mortality rates after major hepatectomy were not different between the two groups and it appeared that prehepatectomy rIL-2 at a dose of 12 x 10(6) IU/m2/day was well tolerated. During the postoperative course, the mean lymphocyte count was higher in the rIL-2 group (p < 0.05), without qualitative modification of the lymphocyte subsets. Immunological modifications were dose related. High cytotoxicity against K562 and DAUDI cells was constant at the 12 x 10(6) dose level. CONCLUSIONS: Preoperative five-day infusion of rIL-2 before major hepatectomy for colorectal metastases is well tolerated and reverses postoperative immunodepression.
Adenocarcinoma↗
The decreased expression of CD3 zeta chains in cancer patients is not reversed by IL-2 administration.
The mechanisms underlying the impaired immune response frequently observed in cancer patients are poorly understood. Recently, a decreased expression of the signal-transducing CD3 zeta chains has been shown to occur in patients with colorectal or renal-cell carcinoma. Here, we have investigated the expression of the zeta molecule on lymphocytes from patients with advanced cancers including renal-cell carcinoma (n = 21), hepatic colorectal carcinoma metastases (n = 6), head-and-neck squamous-cell carcinoma (n = 7) or miscellaneous tumors (n = 7), using flow cytometry analysis of PBMCs with monoclonal antibody specific for the cytoplasmic domain of the zeta chain. The same analysis was also performed with patients undergoing IL-2 therapy (from 5 days up to 3 months i.v. or s.c.). PBMCs from patients (n = 41) showed a significant decrease in expression of the zeta chains as compared to the levels found in lymphocytes from healthy controls (n = 15), which was not reversed by IL-2 administration. Together, these results suggest that an alteration in the expression of the zeta-chain-transducing element in PBMCs may be a common cause of progressive immunosuppression in advanced cancer patients and that IL-2 is not sufficient to reverse this situation in vivo.
Antigens, Neoplasm↗
Surface expression of functional T cell receptor chains formed by interlocus recombination on human T lymphocytes.
Structural diversity of lymphocyte antigen receptors (the immunoglobulin [Ig] of B cells and the alpha/beta or gamma/delta T cell receptor [TCR] of T cells) is generated through somatic rearrangements of V, D, and J gene segments. Classically, these recombination events involve gene segments from the same Ig or TCR locus. However, occurrence of "trans" rearrangements between distinct loci has also been described, although in no instances was the surface expression of the corresponding protein under normal physiological conditions demonstrated. Here we show that hybrid TCR genes generated by trans rearrangement between V gamma and (D) J beta elements are translated into functional antigen receptor chains, paired with TCR alpha chains. Like classical alpha/beta T cells, cells expressing these hybrid TCR chains express either CD4 or CD8 coreceptors and are frequently alloreactive. These results have several implications in terms of T cell repertoire selection and relationships between TCR structure and specificity. First, they suggest that TCR alloreactivity is determined by the repertoire selection processes operating during lymphocyte development rather than by structural features specific to V alpha V beta regions. Second, they suggest the existence of close structural relationships between gamma/delta and alpha/beta TCR and more particularly, between V gamma and V beta regions. Finally, since a significant fraction of PBL (at least 1/10(4)) expressed hybrid TCR chains on their surface, these observations indicate that trans rearrangements significantly contribute to the combinatorial diversification of the peripheral immune repertoire.
Antibodies, Monoclonal↗
T cell repertoire in patients with B chronic lymphocytic leukemia. Evidence for multiple in vivo T cell clonal expansions.
To characterize circulating T cell subpopulations in B chronic lymphocytic leukemia patients, TCR V alpha and V beta gene-segment use was analyzed by PCR using a panel of V gene-segment subfamily-specific oligonucleotide primers (V alpha 1-29/V beta 1-24). Virtually all V alpha and V beta subfamily specificities were expressed in these patients (nine stage A and four stage C), and the mean values obtained for each specificity were similar to those of a group of 13 healthy donors. Nonetheless, individual analysis revealed that unique V alpha or V beta gene-segment transcripts were overrepresented in patients compared with the control group. Overrepresentation of some TCR V beta chains was also detected by cytofluorometric analysis using a panel of 18 anti-V beta-specific mAbs. To further characterize these T cell subpopulations, we sequenced five different V beta-C beta PCR products in two selected stage A patients and found highly predominant recurrent transcripts in each of the five V beta specificities (50% to 100% of the analyzed sequences with identical V(D)J regions). These results were confirmed on bulk cDNA (i.e., without cloning) and extended to other V beta specificities (up to nine clonal expansions of 24 V beta specificities in one patient) and two other patients using a PCR-based method that determines V(D)J junction size patterns. Finally, it was observed that a V beta 19+ T cell subpopulation was clonally expanded in one patient to up to 30% of circulating T cells. This V beta 19+ CD8+ T cell clone was shown to specifically recognize the autologous tumor cells in vitro, as determined in cytokine release assays. Together, these results support the view that multiple expansions of unique T cell clones may derive in vivo from B chronic lymphocytic leukemia tumor-associated Ag stimulation.
Aged↗
In vivo T-cell clonal amplification at time of acute graft-versus-host disease.
In a series of patients transplanted with HLA-matched allogeneic bone marrow grafts (alloBMT), we previously showed that a few T-cell receptor (TCR) V alpha and V beta gene segment transcripts were overexpressed in skin compared with blood at the time of acute graft-versus-host disease (aGVHD). Here, in one selected patient with overexpressed V beta 16 and V alpha 11 transcripts in skin, we analyzed the junctional variability of these transcripts in donor blood, patient blood, and skin collected at aGVHD onset. A unique junctional region sequence accounted for 81% of in frame V beta 16 transcripts (13 of 16) in skin and 59% (13 of 22) in patient blood. Similarly, two recurrent junctional region sequences were found in skin V alpha 11 transcripts, one accounting for 66% (21 of 32) and the other for 16% (5 of 32). These recurrences were also found in patient blood (36% and 15% of V alpha 11 transcripts, respectively). To extend our analysis, a polymerase chain reaction (PCR)-based method was used to precisely determine TCR beta transcript length in run-off reactions using uncloned bulk cDNA samples. All V beta-C beta PCR products analyzed in donor blood, as well as the majority of those analyzed in patient blood, included transcripts with highly diverse junctional region sizes. As expected from the sequence data, most V beta 16-C beta PCR products in skin and patient blood were of the same size (ie, same junctional region). In addition, V beta 3, V beta 5, and V beta 17 transcripts in skin were shown to display highly restricted size variability. The clonality of the V beta 16-C beta and V beta 17-C beta transcripts was further supported by the results of run-off reactions using 13 J beta specific primers. We have identified several recurrent TCR transcripts in skin, some of them also present in patient blood. These data support the view that several T-cell subpopulations are clonally expanded in vivo at the time of aGVHD onset in this case of related HLA-matched alloBMT.
Adult↗
Human TCR-gamma/delta alloreactive response to HLA-DR molecules. Comparison with response of TCR-alpha/beta.
We have analyzed the human gamma/delta T cell alloreactive response to class II HLA-DR molecules and attempted to compare this response with that mediated by the TCR-alpha/beta counterparts. Several gamma/delta CTL clones from a healthy individual were generated in mixed lymphocyte reactions against an EBV-transformed B cell line termed E418. Fine specificity and primary TCR structure of 10 representative clones (all CD4- CD8 +/-) were then determined. Functional studies, with the use of B cell lines homozygous for HLA-DR (DR1-10), indicated that all gamma/delta T cell clones specifically reacted with HLA-DR2 molecules. In addition, five clones were able to cross-react with subtypes of HLA-DR8. Extended panel target experiments, including lymphoblastoid cells expressing various HLA-DR2 subtypes, showed that the T cell clones displayed distinct fine specificities. Clones with broad (Dw2, Dw12, Dw21, Dw8.1, and Dw8.2) or in contrast, more restricted (DRB1*1501 or DRB1*1503) specificity were identified. Furthermore, amino acid substitutions at predicted peptide binding site position 30 and TCR-interacting position 67 of the DRB*1 beta-chain seemed to affect alloresponse of some T cell clones. With respect to TCR-gamma/delta structure, diversity in gene segment usage was observed, with the predominance of T cells using a V3-J gamma 2/V1-J delta 1+ receptor. A smaller fraction of the cells expressed TCR comprising V gamma 9 and V delta 1 regions. In contrast, the V delta 3 gene segment was used by a minority of the cells, and the V delta 2 was not expressed by any T cell clone. Together, the present data indicate that similarly to TCR-alpha/beta, human TCR-gamma/delta lymphocytes may recognize in a highly specific fashion a particular HLA-DR heterodimer. T cell clones cross-reacting with other HLA-DR molecules were also identified. Despite some degree of heterogeneity, V gene segment use by alloreactive clones seemed to be nonrandom. No obvious correlation between TCR gene use and HLA-DR alloreactivity could be identified. Moreover, our results suggest that similarly to TCR-alpha/beta cells, foreign MHC-bound peptides may contribute to TCR-gamma/delta alloreactive response.
Amino Acid Sequence↗
Metastatic renal-cell carcinoma patients treated with interleukin 2 or interleukin 2 plus interferon gamma: immunological monitoring.
We investigated the biological response of 73 patients with metastatic renal-cell carcinoma (MRCC) treated by repetitive weekly cycles of high-dose interleukin 2 (IL-2) (protocol 1, 40 patients) or IL-2 plus interferon-gamma (IFN-gamma) (protocol 2, 33 patients). The objectives of this study were (i) to evaluate the effects of this IL-2 administration schedule on biological response, (ii) to compare the effects of IL-2 alone with those of IL-2 plus IFN-gamma, (iii) to search for any correlation between certain biological marker values and the clinical response to treatment. Mean CD56+ lymphocyte counts (i.e., NK cells) were significantly higher than those of CD3+ cells in the 2 protocols and a subpopulation of CD56bright cells in protocol 1 was found to be preferentially expanded in vivo. Cytotoxic activity against K562 and Daudi cell lines as well as TNF-alpha and sTNF-alpha R (but not IL-6) significantly increased following treatment. Comparison of the data obtained from patients treated with IL-2 alone vs. IL-2 plus IFN-gamma did not show any significant changes except for eosinophilia (higher in protocol 1). Therefore, addition of IFN-gamma did not affect either lymphocyte distribution or non-MHC-restricted cytotoxicity in vivo. No difference in cell subpopulation or cytotoxicity was detected between responders and non-responders. Pre-treatment sTNF-alpha R concentration, in contrast to IL-6 and TNF-alpha, was significantly higher in progressive than in stable and responder groups, suggesting that this parameter may be predictive of the clinical response.
Carcinoma, Renal Cell↗
Evidence for T-cell clonal expansion in a patient with squamous cell carcinoma of the head and neck.
Squamous cell carcinomas of the head and neck (SCCHN) often contain a large mononuclear cell infiltrate, composed mainly of T-lymphocytes which could reflect an in situ immune reaction against the malignant SCCHN cells. We analyzed the molecular structure of the T-cell receptor (TCR) alpha and beta chains expressed by lymphocytes in the tumor, peripheral blood (PBMC), and in the peritumoral tissue in six cases of localized SCCHN. We first determined V alpha and V beta gene segment subfamily usage by polymerase chain reaction using a panel of V subfamily-specific oligonucleotide primers (V alpha 1-w29 and V beta 1-w24). An apparently unrestricted usage of V alpha or V beta gene segment subfamilies was observed for all three samples from the six cases examined. No major difference was observed in T-cell receptor repertoire expression of PBMC between SCCHN and healthy donors, making unlikely the expression of putative tumor-related superantigen(s) in these patients. Intersample comparisons for a given V alpha or V beta T-cell receptor specificity revealed some differences in V gene segment usage in tumor-infiltrating lymphocytes versus PBMC. A detailed analysis of these V segment subfamily specificities (cloning followed by sequencing and CDR3 size distribution analysis) in one patient revealed the presence of recurrent T-cell receptor transcripts (i.e., identical V-N-J sequences) in the tumor (e.g., 40%) and in PBMC (e.g., 75%). These results show that unique T-cell subpopulations are clonally amplified in SCCHN patients, possibly as a consequence of antigen-driven selection.
Adult↗