Flow-cytometric analysis of T-cell receptor expression in peripheral blood lymphocytes.

BACKGROUND Lymphocytes of subjects sensitized to the insect-derived allergen Chi t 1-9 are, in response to the allergen, characterized by an elevated proliferation and increased expression of activation markers such as HLA-DR and CD25 in vitro. A restriction for HLA-DR B1 in monosensitized patients was found. OBJECTIVE The aim of this study was to investigate whether the response to the allergen Chi t 1-9 involves the preferential cell surface expression of a specific alpha/beta T-cell receptor type. METHODS The T-cell receptor repertoire was measured with 7 monoclonal antibodies to epitopes on the variable region of the alpha- and beta-chain by flow cytometry. Cell lines of 9 patients were established with Chi t 1-9, 6 with tetanus toxoid and 6 with phytohaemagglutinin in the presence of interleukin 2. In addition, non-stimulated lymphocytes as well as lymphocytes of 5 non-sensitized controls exposed to Chi t 1-9 were examined. RESULTS Each of the 9 sensitized and 5 control subjects studied showed an individual pattern of lymphocyte expression for each T-cell receptor specificity. However, after stimulation specific to Chi t 1-9 for 2 weeks, a significant increase in V beta 8-expressing cells was measurable only in patients sensitized to Chi t 1-9. The cells of the 5 control subjects showed no significant changes due to the allergen stimulation. CONCLUSION These data suggest that the expression of certain T-cell receptor types plays an important role in the development of Chi t 1-9 allergy.