[Mechanism of EA-rosette formation blockade by antisera against cell surface antigens].

The effect of different antisera to cell surface antigens on EA-rosette formation was investigated. Anti-immunoglobulin serum causes almost total blockade of EA-rosette formation by murine spleen and bone marrow cells. Rabbit anti-mouse brain-associated theta-antigen immunoglobulin has the same effect on EA-rosette formation by murine splenocytes but it has a slight action on EA-rosette formation by rat splenocytes. The mixing of rat splenocytes and autologous or mouse thymocytes increased the blocking influence of anti-BA theta-immunoglobulin. These findings indicate a requirement for specific antigen in the test-system for blockade of EA-rosette formation. This antigen is not necessarily expressed on the surface of Fc-receptor-bearing cells.