ETUDE DE LA REPONSE CTL DANS DEUX MODELES DE TUMEURS SOLIDES (LES CANCERS BRONCHIQUES NON A PETITES CELLULES ET LE LYMPHOME T CUTANE. CLONAGE DES ANTIGENES ASSOCIES A UN CARCINOME BRONCHIQUE A LARGES CELLULES)

PARIS12-CRETEIL BU Multidisc. (940282102) / SudocSudocFranceF

Functional Inhibitory Receptors Expressed by a Cutaneous T Cell Lymphoma-Specific Cytolytic Clonal T Cell Population

Inhibitory receptors on natural killer cells and on a minority of T lymphocytes are major histocompatibility complex class Ia or Ib specific. We have previously reported several tumor-specific cytotoxic T cell clones infiltrating a CD4+ Vβ13+ cutaneous T cell lymphoma. These clones mediated a specific major histocompatibility complex class I-restricted cytotoxic activity toward the uncultured tumor cells and autologous long-term tumor T cell lines. In this study, we cultured with interleukin-2 the peripheral blood lymphocytes of the same patient a few weeks before invasion of the blood by tumor cells. We report the rapid and selective expansion of a CD8+ Vβ13+ lymphoid population. This population was clonal, as it expressed a unique T cell receptor-Vβ junctional region. Vβ13+ tumor cells and Vβ13+ reactive T cells were shown to have different junctional sequences. The CD8+ reactive clone was functional, as it had a specific autologous tumor-specific, human leukocyte antigen-A2 restricted, cytotoxic activity. This clone coexpressed high levels of CD158a, CD158b, p70, and CD94/NKG2A inhibitory receptors. Interestingly, we found that anti-CD158a and anti-CD158b monoclonal antibodies could inhibit anti-CD3 redirected cytotoxicity mediated by the reactive clonal population. Further, an anti-human leukocyte antigen-B/C monoclonal antibody enhanced the specific cytotoxic activity of the clone against autologous tumor cells. These results are the first evidence that inhibitory receptor expression can lead to the inhibition of cutaneous T cell lymphoma-specific T cell responses

A point mutation in the alpha-actinin-4 gene generates an antigenic peptide recognized by autologous cytolytic T lymphocytes on a human lung carcinoma

We have identified an antigen recognized on a human large cell carcinoma by an autologous tumor-specific CTL clone that was derived from mononuclear cells infiltrating the primary tumor. The antigenic peptide is presented by HLA-A2 molecules and is encoded by the alpha -actinin-4 gene, which is expressed ubiquitously. In the tumor cells, a point mutation generates an amino-acid change that is essential for recognition by the CTLs, The mutation was not found in alpha -actinin-4 cDNA sequences from about 50 lung carcinoma cell lines, suggesting that it is unique to this patient. Although he did not receive chemotherapy or radiotherapy, the patient has been without evidence of tumor since the resection of the primary lesion in 1996, Using tetramers of soluble HLA-A2 molecules loaded with the mutated antigenic peptide, anti-alpha -actinin-4 CTLs could be derived from blood samples collected from the patient in 1998 and 2000, It is possible that these CTLs, recognizing a truly tumor-specific antigen, play a role in the clinical evolution of this lung cancer patient

Cutaneous T cell lymphoma reactive CD4+ cytotoxic T lymphocyte clones display a Th1 cytokine profile and use a Fas-independent pathway for specific tumor cell lysis

We have previously described two cytotoxic T lymphocyte clones isolated from lymphocytes infiltrating a human major histocompatibility complex class II–/class I+, CD4+ cutaneous T cell lymphoma. These clones displayed a CD4+CD8dim+ (TC5) and CD4+ CD8– (TC7) phenotype and mediated a specific major histocompatibility complex class I-restricted cytotoxic activity toward Cou-LB autologous tumor cell line. Our studies were performed to elucidate the mechanism involved in T-cell-clone-mediated cytotoxicity and to determine the cytokine profile of both the lymphoma cell line and specific cytotoxic T lymphocyte clones. The results indicate that, despite surface expression of Fas receptor on Cou-LB and Fas ligand induction on TC5 and TC7 cell membranes, the CD4+ cytotoxic T lymphocyte clones do not use this cytotoxic mechanism to lyse their specific target. The TC7 clone uses instead a granzyme–perforin-dependent pathway. Furthermore, quantitative analysis of Th1 and Th2 cytokine mRNA expression in the cutaneous T cell lymphoma cell line as well as in TC5 and TC7 clones indicated that, whereas the tumor cells display a Th2-type profile (interleukin-4, interleukin-6, and interleukin-10), the cytotoxic T lymphocyte clones express Th1-type cytokines (interferon-γ, granulocyte macrophage colony stimulating factor, and interleukin-2). In addition, preincubation of the tumor-infiltrating lymphocyte clones with autologous tumor cells induced their activation and subsequent amplification of the Th1-type response. These results indicate a direct contribution of the malignant cells in the Th1/Th2 imbalance observed frequently in cutaneous T cell lymphoma patients and suggest their potential role in depressed cell-mediated immunity. Identification of CD4+ Th1-type cytotoxic T lymphocyte clones, the tumor antigen they recognize, and optimization of their cytokine expression profile should be useful for the design of new immunotherapy protocols in cutaneous T cell lymphoma

Preprocalcitonin signal peptide generates a cytotoxic T lymphocyte-defined tumor epitope processed by a proteasome-independent pathway

We identified an antigen recognized on a human non-small-cell lung carcinoma by a cytotoxic T lymphocyte clone derived from autologous tumor-infiltrating lymphocytes. The antigenic peptide is presented by HLA-A2 and is encoded by the CALCA gene, which codes for calcitonin and for the α-calcitonin gene-related peptide. The peptide is derived from the carboxy-terminal region of the preprocalcitonin signal peptide and is processed independently of proteasomes and the transporter associated with antigen processing. Processing occurs within the endoplasmic reticulum of all tumoral and normal cells tested, including dendritic cells, and it involves signal peptidase and the aspartic protease, signal peptide peptidase. The CALCA gene is overexpressed in medullary thyroid carcinomas and in several lung carcinomas compared with normal tissues, leading to recognition by the T cell clone. This new epitope is, therefore, a promising candidate for cancer immunotherapy