Expression of the gangliosides GD3 and GD2 on lymphocytes in tissue sections of melanoma

Previous studies in vitro have shown that monoclonal antibodies (MAbs) against gangliosides GD3 and GD2 potentiate lymphocyte responses to a variety of stimuli. The purpose of the present study was to determine by immunohistological techniques whether GD3 and GD2 was expressed on lymphoid cells in vivo around melanoma cells. Studies on metastases in lymph nodes indicated that the lymphoid infiltrate around the margins of the metastases was predominantly CD4+ T cells, which were shown by dual labelling techniques to express mainly GD2 and to a lesser extent GD3. CD4+GD3+ T cells were detected more frequently in cortical regions of the lymph nodes. CD8+ T cells were less numerous than CD4+ T cells and expressed both GD3 and GD2. Expression of GD2 was also prominent on CD4+ T cells, B lymphocytes and dendritic reticular cells in germinal centres, whereas GD3 was mainly expressed on T cells in the margins of the follicles. In contrast to the predominance of CD4+ T cells in lymph nodes, CD4+ and CD8+ T cells were in approximately equal proportions about primary melanoma and metastases in skin. GD2 was largely undetectable on lymphocytes at these sites. In contrast, GD3 was detected on both CD8+ and CD4+ lymphocytes but not on B lymphocytes. The absence of GD2 on CD4+ T cells in skin suggested the latter were a different subpopulation to those in lymph nodes. There appeared to be no clear correlation, however, with subsets of CD4 T cells defined by the 2H4 and Leu 8 MAbs.(ABSTRACT TRUNCATED AT 250 WORDS)