Immunohistological analysis of skin reaction to My1 derived from Mycobacterium leprae.

A study was made on the in situ characteristics of dermal infiltrates in a 24-hr skin reaction using monoclonal antibodies defining T-cell subsets, Ia-like antigens, Langerhans' cells, My1, and indirect immunofluorescence. The skin reaction was induced by the mycobacterial antigen My1 derived from Mycobacterium leprae. In all, 10 biopsies were studied. The infiltrates were composed of lymphocytes and polymorphonuclear leukocytes. The predominant lymphocytes in the infiltrates were activated T lymphocytes expressing OKT11, Leu3a, OKT8, and Ia-like antigens. The ratio of Leu3a+:OKT8+ cells was 1.2 +/- 0.50. Some of the cells in the infiltrates showed the presence of My1, as seen by the staining with MLO6 monoclonal antibody. No difference was observed in the numbers of OKT6+ epidermal Langerhans' cells in the skin of My1 reaction biopsies and those of normal individuals.