Nonidiotypic V H antigens can be detected on human lymphocytes

Abstract

Human peripheral blood B and T lymphocytes, thymocytes, as well as mononuclear cells from patients with chronic lymphocytic leukemias (CLL) were analyzed for surface-bound V H antigens using an indirect immunofluorescence (IF) technique. A rabbit antiserum raised against a fragment corresponding to the variable region of the IgG3k myeloma protein Kup was used. Anti-V H antiserum and anti-F (ab′) 2 antiserum reacted similarly with unfractionated lymphocytes and T-cell-depleted normal peripheral blood lymphocytes. This was also seen when CLL cells were stained. Thymocytes were not positively stained. In contrast a proportion of the peripheral blood T lymphocytes sometimes showed a faint positive staining. Anti-V H antiserum was also used to inhibit allogeneic and autologous mixed lymphocyte reactions (MLR). A significant inhibition of the lymphocyte responses in allogeneic MLR was seen when a stimulator/responder cell ratio of 20 100 was used. No inhibition was obtained using a stimulator/responder cell ratio of 100 100 . Autologous MLR lymphocyte responses were also strongly inhibited by anti-V H antiserum. Thus the results obtained with the functional assays further strengthen the anticipation that peripheral blood T lymphocytes bear V H antigens and that these antigens may be integral parts of the T-cell receptor for antigen.