INTRACYTOPLASMATIC AND MEMBRANE EXPRESSION OF 28-KDA, 65-KDA, AND 70-KDA HEAT-SHOCK PROTEINS ON LYMPHOMONOCYTOID TUMOR-CELL LINES

The expression of heat shock proteins (HSP) in the cytoplasm and at th e surface of several lymphoid (T and B) and monocytoid cell lines was analysed by immunoprecipitation and flow cytometry. Murine monoclonal antibodies MoAbs: SPA-800, ML30, RPN1197 and HSP01 were specific for H SP28-, 65- and 70-kDa respectively. Moreover, ML30 and RPN1197 are als o used in antibody-dependent cell cytotoxicity, using peripheral blood lymphocytes as effector cells and tumour cells as targets. The result s obtained with these techniques suggested that all the cell lines, ex pressed HSPs, or at least their epitopes, on the cell surface. Such ex pression can be observed either constitutively (U937, HL60 and Daudi c ell lines) or after hyperthermic treatment (H9 cells). In contrast, ei ther normal or heat stressed lymphocytes showed no surface expression of HSPs. Altogether these results suggest a correlation between membra ne expression and cell transformation.