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Human epidermis contains a phenotypically heterogeneous population of T cells. No information, however, is available regarding the TCR repertoire of these T cells and their relevant physiologic and pathologic functions in vivu. To this end, T cells were prepared from the lesional epidermis in two patients with fixed drug eruption (FDE) and their phenotype, function and TCR repertoire were examined in parallel. Both epidermal T cells, termed FDE-1 and -2 cells, respectively, expressed αβ TCR, but displayed some phenolypic heterogeneity. These T cells were induced to display cytolytic activity by ligation of the CD3/TCR-αβ complex. Comparative analyses of TCR Vα and Vβ expression in the epidermal T cells and the paired peripheral blood lymphocytes (PBL) by quantitative polymerase chain reaction (PCR) demonstrated that the epidermal T cells, but not the paired PBL, utilized a very limited range of Vα and Vβ genes. These results indicate that some expansion or preferential migration of epidermal T cells that recognize a restricted set of antigens expressed within the epidermis could occur in situ following ingestion of the causative drug. The persistence of these epidermal T cells in FDE lesions suggests their pathologic role in a drug-induced flare. [ABSTRACT FROM AUTHOR]

The effect of sheep red blood cells (SRBC) fragments on rosette formation of human peripheral T lymphocytes with SRBC was evaluated on the active and total T-rosette tests. The rosetting capacity of active rosette-forming cells was selectively and nearly completely inhibited by the pretreatment of lymphocytes with SRBC fragments. The decrease in total rosettes by blocking with SRBC fragments was almost parallel to that of active rosettes. SRBC fragments had no inhibitory effect on the rosetting capacity of a lymphocyte population in which active rosette- forming cells were removed by gradient centrifugation. These results suggested that active rosette-forming cells in human T lymphocytes have the receptors of high affinity for SRBC and these receptors readily bind SRBC fragments, resulting in block of rosette formation. [ABSTRACT FROM AUTHOR]

The generation of immunoglobulin-producing cells from human peripheral blood lymphocytes in pokeweed mitogen-stimulated cultures was significantly suppressed by levamisole. Greatest suppression was observed when cells were incubated with levamisole at a concentration of 10-6 M for 20 min or more prior to culture. Such suppression occurred when untreated as well as levamisole-treated B cells were co-cultured only with levamisole-treated T cells. Adding of levamisole-treated T cells to a combination of untreated autologous B and T cells resulted in the suppression of B cell differentiation. The results suggest that levamisole treatment of lymphocytes exerts suppression on pokeweed mitogen-induced B cell differentiation through its effect on T cell regulatory properties. [ABSTRACT FROM AUTHOR]