Analysis of T-cell-receptor variable gene segment usage in peripheral-blood lymphocytes of advanced cancer patients

Clonal expansion of renal cell carcinoma-infiltrating T lymphocytes

T lymphocytes can mediate the destruction of cancer cells by virtue of their ability to recognize tumor-derived antigenic peptides that are presented on the cell surface in complex with HLA molecules and expand. Thus, the presence of clonally expanded T cells within neoplastic lesions is an indication of ongoing HLA-restricted T cell-mediated immune responses. Multiple tumors, including renal cell carcinomas (RCCs), are often infiltrated by significant amounts of T cells, the so-called tumor-infiltrating lymphocytes (TILs). In the present study, we analyzed RCC lesions (n = 13) for the presence of expanded T-cell clonotypes using T-cell receptor clonotype mapping. Surprisingly, we found that RCCs comprise relatively low numbers of distinct expanded T-cell clonotypes as compared with melanoma lesions. The numbers of different T-cell clonotypes detected among RCC-infiltrating lymphocytes were in the range of 1–17 (median = 5), and in several patients, the number of clonotypes expanded within tumor lesions resembled that observed among autologous peripheral blood mononuclear cells. Moreover, several of these clonotypes were identical in TILs and PBMCs. Flow cytometry data demonstrated that the general differentiation status of CD8⁺ TILs differed from that of circulating CD8⁺ T cells. Furthermore, PD-1 and LAG-3 were expressed by a significantly higher percentage of CD8⁺ RCC-infiltrating lymphocytes as compared with PBMCs obtained from RCC patients or healthy individuals. Thus, CD8⁺ TILs display a differentiated phenotype and express activation markers as well as surface molecules associated with the inhibition of T-cell functions. However, TILs are characterized by a low amount of expanded T-cell clonotypes.

Gene expression profile of peripheral blood lymphocytes from renal cell carcinoma patients treated with IL-2, interferon-α and dendritic cell vaccine

Lymphocytes are a key component of the immune system and their differentiation and function are directly influenced by cancer. We examined peripheral blood lymphocyte (PBL) gene expression as a biomarker of illness and treatment effect using the Affymetrix Human Gene ST1 platform in patients with metastatic renal cell carcinoma (mRCC) who received combined treatment with IL-2, interferon-?-2a and dendritic cell vaccine. We examined gene expression, cytokine levels in patient serum and lymphocyte subsets as determined by flow cytometry (FCM). Pre-treatment PBLs from patients with mRCC exhibit a gene expression profile and serum cytokine profile consistent with inflammation and proliferation not found in healthy donors (HD). PBL gene expression from patients with mRCC showed increased mRNA of genes involved with T-cell and T_REG-cell activation pathways, which was also reflected in lymphocyte subset distribution. Overall, PBL gene expression post-treatment (POST) was not significantly different than pre-treatment (PRE). Nevertheless, treatment related changes in gene expression (post-treatment minus pre-treatment) revealed an increased expression of T-cell and B-cell receptor signaling pathways in responding (R) patients compared to non-responding (NR) patients. In addition, we observed down-regulation of T_REG-cell pathways post-treatment in R vs. NR patients. While exploratory in nature, this study supports the hypothesis that enhanced inflammatory cytotoxic pathways coupled with blunting of the regulatory pathways is necessary for effective anti-cancer activity associated with immune therapy. This type of analysis can potentially identify additional immune therapeutic targets in patients with mRCC.

T-cell receptor beta chain variability in bone marrow and peripheral blood in severe acquired aplastic anemia

Aplastic anemia (AA) is characterized by multilineage bone marrow failure of unknown etiology. In order to assess the role of immune-mediated mechanisms in hematopoietic suppression, we examined the diversity of T lymphocyte repertoire in terms of variable (V) gene segment usage of the T cell receptor (TCR) beta chain in bone marrow and peripheral blood of six patients with severe untreated AA. Expression of transcripts encoding Vbeta1-Vbeta24 subfamilies was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). The results revealed that T lymphocytes in AA utilize highly diverse segments of the beta chain loci. Over the heterogenous Vbeta expression background, transcripts encoding Vbeta3, Vbeta20, Vbeta21, and Vbeta22 subfamilies were enhanced by at least threefold in 5 of 6 patients as compared to normal samples, but a different transcript species was over expressed in each patient. To evaluate clonality of T cells, size diversity within the complementarity determining region 3 (CDR3) and usage of TCRbeta joining (J) gene segments were analyzed in PCR products specific for each of the 24 Vbeta subfamilies. We found that the majority of transcripts display normal CDR3 size patterns, as is characteristic of polyclonal populations. Nevertheless, one or two predominating junctional rearrangements were observed in each patient. They were identified in Vbeta5, Vbeta7, Vbeta8, Vbeta13, Vbeta15, Vbeta16, and Vbeta23 transcripts, which differed from patient to patient and did not correspond to transcripts with an abnormally high expression level. Our results demonstrate that T cell repertoire in AA is random with respect to the TCR beta chain. Unique rearrangements detected in the CDR3 region are suggestive of a limited process of an antigen-driven (oligo)clonal T cell expansion which may take place over the overwhelmingly polyclonal repertoire of T lymphocytes at the onset of severe AA.

Lymphocytes infiltrating colorectal cancer have low proliferative capacity but can secrete normal levels of interferon gamma

Significant numbers of infiltrating mononuclear cells are commonly observed in solid tumours, although their role in restricting tumour growth is not clear. Tumour-infiltrating lymphocytes (TIL) from 38 patients with colorectal cancer, in parallel with peripheral blood lymphocytes (PBL), were assayed to determine their ability to proliferate in response to concanavalin A (ConA), interleukin-2 (IL-2), ConA+IL-2, phorbol 12-myristate 13-acetate (PMA)+ionomycin ionomycin (IOM), and staphylococcal enterotoxin B(SEB). These reagents were selected to give a range of weak to strong proliferative responses either via or independent of the T cell receptor. Proliferation of TIL was significantly lower than that of PBL in all cultures: ConA (P < 0.001), IL-2 (P = 0.002), ConA+IL-2 (P < 0.001), PMA+IOM (P < 0.001), SEB (P = 0.002). In addition to the low proliferative capacity of TIL, production of cytokines by TIL may also play a role in control of tumour growth. We have assayed IFN gamma production in the supernatants from 16 paired TIL and PBL cultures, and tumour necrosis factor alpha (TNF alpha) in 6 paired cultures. TNF alpha concentrations were significantly lower in TIL cultures than in PBL cultures stimulated with ConA (P < 0.05), but no different in control or IL-2 stimulated cultures. IFN gamma levels did not significantly differ between PBL and TIL cultures, indicating that despite the restricted proliferative capacity of TIL, these cells remain capable of secreting significant amounts of IFN gamma.

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.

Characterization of T-cell receptor V beta repertoire in ovarian tumour-reacting CD3+ CD8+ CD4- CTL lines

T cells from tumour infiltrating lymphocytes (TIL) cultured in media containing IL-2 were shown to mediate in vitro and in vivo antitumor responses. To characterize the T-cell antigen receptor (TCR) V beta expression in autologous cytotoxic effectors we isolated CD3+ CD8+ CD4- cells from cultures of TIL and tumour-associated lymphocytes (TAL) and analysed the TCR V beta repertoire of CD3+ CD8+ CD4- lines of known HLA-A, -B and -C phenotype, using polymerase chain reaction (PCR). These lines showed preferential lysis of autologous tumours and lysed, to a much lesser extent, NK and LAK cell-sensitive targets. Tumour lysis was inhibited by antibodies to CD3 and MHC class I antigens indicating that they are cytotoxic T lymphocytes (CTL). These CD8+ CTL lines expressed a broad distribution of TCR V beta repertoire which was dominated by particular groups of V beta families in each CTL line. However, no predominant expression of one or the same V beta segment in all CTL lines was observed although statistical correlations between V beta family usage and magnitude of the antitumour cytolytic response were found. These results suggest that certain TCR V beta families may be selected by antigen in ovarian tumour-reactive T cells and this selection may be affected by Ag expression, and/or host factors. To our knowledge, this is the first documentation of TCR V beta repertoire of human ovarian tumour-reactive CD3+ CD8+ CD4- CTL from different individuals of known HLA types.