FLOW-CYTOMETRIC ANALYSIS OF T-CELL RECEPTOR EXPRESSION IN PERIPHERAL-BLOOD LYMPHOCYTES

Background: Lymphocytes of subjects sensitized to the insect-derived a llergen Chi t 1-9 are, in response to the allergen, characterized by a n elevated proliferation and increased expression of activation marker s such as HLA-DR and CD25 in vitro. A restriction for HLA-DR B1 in mon osensitized patients was found. Objective: The aim of this study was t o investigate whether the response to the allergen Chi t 1-9 involves the preferential cell surface expression of a specific alpha/beta T-ce ll receptor type. Methods: The T-cell receptor repertoire was measured with 7 monoclonal antibodies to epitopes on the variable region of th e alpha- and beta-chain by flow cytometry. Cell lines of 9 patients we re established with Chi t 1-9, 6 with tetanus toroid and 6 with phytoh aemagglutinin in the presence of interleukin 2. In addition, non-stimu lated 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 lymphoc yte expression for each T-cell receptor specificity. However, after st imulation 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 significan t changes due to the allergen stimulation. Conclusion: These data sugg est that the expression of certain T-cell receptor types plays an impo rtant role in the development of Chi t 1-9 allergy.