MART1, a human melanoma-specific tumor antigen, was used to induce an increased immune reaction, since a MART1-protective response is required to overcome immune tolerance to the melanoma antigen MelanA.
A dural biopsy was done which showed sheets of poorly differentiated tumor cells which expressed S100 and Melan A and were immunoreactive with Human Melanoma Black (HMB)-45 antibody, consistent with the diagnosis of malignant melanoma.
All samples were positive for beta-actin and MART-1 and all but two were positive for tyrosinase, confirming RNA integrity and the presence of melanoma.
Although immunohistochemical (IHC) stains such as HMB45, Melan A, and S-100 are often utilized; the role of Sry-related HMG-box gene 10 (SOX10) in the diagnosis of melanoma in effusions has not been previously reported.
An improved protocol for reverse transcription-polymerase chain reaction (RT-PCR), amplifying tyrosinase and MelanA/MART-1 mRNA from peripheral blood, was used to test 340 blood samples from 225 patients with malignant melanoma for the presence of circulating tumour cells.
Apart from characteristic histological features of melanoma with intraepidermal involvement, the lesion was immunohistochemically positive for 5100 protein, with HMB45 and A103 (anti-human Melan-A/MART-1), and ultrastructurally showed melanosomes.
Applying the multimer technology, we report here an unexpected high frequency of Melan-A-specific CTLs in a melanoma patient with progressive lymph node metastases, consisting of 18 and 12.8% of total peripheral blood and tumor-infiltrating CD8+ T cells, respectively.
Because of its expression pattern restricted to cells of the melanocytic lineage and to melanoma cells, Melan-A is an important target of immunotherapeutic approaches for the treatment of melanoma.
By T cell receptor clonotypic mapping and staining with tetrameric HLA-peptide complexes, we demonstrate the presence of melanocyte differentiation antigen MART-1 specific T cells in the areas of destruction of both neoplastic and normal melanocytic cells in a case of a primary melanoma and its associated hypopigmentation.
CD8(+) T-cells specific for MART-1-(26-35), a dominant melanoma epitope restricted by human leukocyte antigen (HLA)-A*0201, are exceptionally common in the naive T-cell repertoire.
Dendritic cells loaded with MART-1 peptide or infected with adenoviral construct are functionally equivalent in the induction of tumor-specific cytotoxic T lymphocyte responses in patients with melanoma.
Examination of the specificity of these T cells indicated that 16% of HLA-A1 TIL, 57% of HLA-A2 TIL, 7% of HLA-A3 TIL, 13% of HLA-A24 TIL, and 27% of HLA-A31 TIL recognized shared melanoma antigens restricted by major histocompatibility complex class I. Melanosomal proteins were frequently recognized by these TIL, and MART-1(27-35), gp100(154-162), gp100(209-217), and gp100(280-288) represent highly immunogenic epitopes that were recognized by a high percentage of HLA-A2 restricted melanoma reactive TIL.
Functional CD8+ T cells against several human tumor antigens were induced, and those against the Melan-A melanoma antigen used similar TCRs to those that have been detected in T cell clones from individuals with autoimmune vitiligo or melanoma.
HLA-A2-restricted TCR-transduced (TD) CIK directed against the melanoma antigens Mart1 and NY-ESO1 were generated by lentiviral transduction and successfully expanded over a 3-4-week period.
However, not all IHC-positive cells in SLN are metastatic melanoma, as evidenced by the presence of MART-1 positive cells in SLN from breast cancer patients with no history of melanoma (so-called 'false-positive' cells).