We recently isolated a cDNA clone that encodes the melanocyte lineage-specific antigen glycoprotein (gp)100. Antibodies directed against gp100 are an important tool in the diagnosis of human melanoma. Since the gp100 antigen is highly expressed in melanocytic cells, we investigated whether this antigen might serve as a target for antimelanoma cytotoxic T lymphocytes (CTL). Here, we demonstrate that cytotoxic tumor-infiltrating lymphocytes (TIL) derived from a melanoma patient (TIL 1200) are directed against gp100. HLA-A2.1+ melanoma cells are lysed by TIL from this patient. In addition, murine double transfectants, expressing both HLA-A2.1 and gp100, are lysed by TIL 1200, whereas transfectants expressing only HLA-A2.1 are not susceptible to lysis. Furthermore, the HLA-A2.1+ melanoma cell line BLM, which lacks gp100 expression and is resistant to lysis, becomes susceptible after transfection of gp100 cDNA. Finally, HLA-A2.1+ normal melanocytes are lysed by TIL 1200. These data demonstrate that the melanocyte differentiation antigen gp100 can be recognized in the context of HLA-A2.1 by CTL from a melanoma patient. Gp100 may therefore constitute a useful target for specific immunotherapy against melanoma, provided that no unacceptable cytotoxicity towards normal tissue is observed.

Purpose: Thus far, dendritic cell (DC)-based immunotherapy of cancer was primarily based on in vitro-generated monocytederived DCs, which require extensive in vitro manipulation. Here, we report on a clinical study exploiting primary CD1c þ myeloid DCs, naturally circulating in the blood. Experimental Design: Fourteen stage IV melanoma patients, without previous systemic treatment for metastatic disease, received autologous CD1c þ myeloid DCs, activated by only brief (16 hours) ex vivo culture and loaded with tumor-associated antigens of tyrosinase and gp100. Results: Our results show that therapeutic vaccination against melanoma with small amounts (3-10 Â 10 6 ) of myeloid DCs is feasible and without substantial toxicity. Four of 14 patients showed long-term progression-free survival (12-35 months), which directly correlated with the development of multifunctional CD8þ T-cell responses in three of these patients. In particular, high CD107a expression, indicative for cytolytic activity, and IFNg as well as TNFa and CCL4 production was observed. Apparently, these T-cell responses are essential to induce tumor regression and promote long-term survival by stalling tumor growth. Conclusions:We show that vaccination of metastatic melanoma patients with primary myeloid DCs is feasible and safe and results in induction of effective antitumor immune responses that coincide with improved progression-free survival. Clin Cancer Res; 22(9); 2155-66. Ó2015 AACR.

Purpose: It is unknown whether the route of administration influences dendritic cell (DC)-based immunotherapy. We compared the effect of intradermal versus intranodal administration of a DC vaccine on induction of immunologic responses in melanoma patients and examined whether concomitant administration of interleukin (IL)-2 increases the efficacy of the DC vaccine.Experimental Design: HLA-A2

Vaccination with CEA-peptide loaded mature DCs induced potent CEA-specific T cell responses in advanced colorectal cancer patients. In this study, antigen-specific T cell responses were readily detected in DTH skin tests, much less in abdominal lymph nodes, and not in peripheral blood and tumor tissue.

Cytotoxic T lymphocytes (CTL) reactive with human mela noma tumor cells occasionally display cross-reactivity with normal melanocytes. Previously, we identified the melanocyte lineage-specific antigen gp 100 that is expressed by both mela noma cells and normal melanocytes, as a target antigen for tumor-infiltrating lymphocytes derived from a melanoma pa tient (TIL 1200). Here, we demonstrate that the oligoclonal HLA-A2.1-restricted TIL 1200 line is reactive with 2 distinct peptides derived from the gplOO protein. CTL that recognize melanoma tumor cells in a T-cellreceptor (TcR)-mediated and MHC-restricted manner have been isolated from tumor-bearing patients (for a review see Knuth et al, 1992). However, the identity of the antigens and epitopes recognized by anti-melanoma CTL remains largely unknown. These CTL often display cross-reactivity with alloge neic HLA-A2.1 matched melanomas, implying that shared melanoma antigens are recognized in the context of HLA-A2.1 (Darrow et ai, 1989; Kawakami et al, 1992), Recently, it has been reported that some CTL react not only with melanoma tumor cells but also with normal melanocytes, suggesting recognition of melanocyte differentiation antigens (Anichini et al, 1993).Using a genetic approach, Boon and colleagues have suc ceeded in identifying a number of antigens recognized by anti-melanoma CTL. Apart from the tumor-specific MAGE-1 and -3 antigens (Van der Bruggen et al, 1991; Gaugler et al, 1994), they also identified the melanocyte lineage-specific tyrosinase protein as a target for melanoma-specific CTL (Brichard et al, 1993). Similarly, we have identified the gplOO melanocyte-specific protein as a target antigen for melanoma tumor-infiltrating lymphocytes (TIL) (Bakker et al, 1994). Recently, another melanocyte differentiation antigen, Melan A/MART-1, was identified as a target for anti-melanoma CTL (Coulieetal, 1994; Kawakami et al, 1994a). Collectively, these findings demonstrate that melanocyte differentiation antigens can be immunogenic.The gplOO antigen is an intracellular glycoprotein of approxi mately 100 kDa and is recognized by MAb NKI-beteb (Vennegoor et al, 1988). Expression of gplOO is restricted to cells of the melanocytic lineage. Recently, we isolated a cDNA clone encoding gplOO (Adema et al, 1993). Characterization of the gplOO cDNA revealed that gplOO is a type-I transmembrane glycoprotein highly homologous to another melanocytespecific protein, Pmell7 (Adema et al, 1994). Introduction of the gplOO encoding cDNA into gp 100-negative BLM cells conferred susceptibility to lysis by tumor-infiltrating lympho cytes derived from a melanoma patient (TIL 1200) (Bakker et al, 1994). Furthermore, short-term cultures of HLA-A2.1+ normal melanocytes were also Iysed by TIL 1200, demonstrat ing that TIL 1200 recognizes the non-mutated gplOO protein.Recently, it has been demonstrated that a naturally pro cessed gplOO peptide (amino acids 280-288) that was identi fied by tandem mass spectroscopy, could direct target-cell lysis by HLA-A2.1+ restricted anti-melanoma...

Abstract. Investigating the regulation of very late antigen (VLA)-mediated functions, we found that TS2/ 16, a mAb directed against the/3 chain of the VLA group of integrins, can induce binding of resting peripheral blood lymphocytes, cloned T lymphocytes, and Epstein Barr virus-transformed B cells to extracellular matrix components, fibronectin, laminin, and collagen, but not to fibrinogen. The antibody stimulates VLA-4-, VLA-5-, and VLA-6-mediated binding. Furthermore, it induces VLA-4-mediated binding to vascular cell adhesion molecule-1 expressed by rTNFor-stimulated endothelial cells, but it does not stimulate homotypic aggregation of cells as described for a number of anti-VLA-4~ antibodies (Bednarczyk,

No abstract

No abstract