The influence of allogeneic or syngeneic cells surface backgrounds on the antibody response of mice to rabbit Fab’ fragments

Recent work has shown that in vitro, the cytotoxic immune response to cell surface antigens is enhanced if the antigen to which the immune response is directed, is on cells bearing major histocompatibility antigens identical to those of the responding cells. This 'H-2 restriction' has been demonstrated in the mouse using virally infected cells, haptenated cells, cells bearing the male Y antigen, and cells differing at the minor histocompatibility loci. Other investigations have shown that antigenic determinants coupled to tolerated antigens or isologous serum proteins, elicit a humoral response which is weaker than that to the same determinant coupled to a heterologous carrier. This and other evidence suggest an inverse relationship between humoral and cell mediated immunity. The purpose of this investigation was to explore the humoral response to antigens on cells which are syngeneic or allogeneic to the recipient, in order to determine the influence of a tolerated as opposed to allogeneic background. The approach used in this study was as follows: Mice were immunized with antigen (rabbit Fab' fragments) attached to syngeneic, allogeneic, or F₁ (semi syngeneic), irradiated spleen cells. Specific anti-rabbit Fab' plaque forming cell numbers were determined five days after the third, weekly injection of Fab' coated spleen cells. Some of the spleen cells taken from the responding animals, on the day of sacrifice, were incubated in vitro with soluble antigen (rabbit Fab' fragments not specific for mouse cells) for four days. The results showed that the humoral response to antigens attached to cells bearing 'self histocompatibility antigens (i.e. syngeneic or F₁ semi syngeneic cells) was significantly weaker than the humoral response to the same antigen on allogeneic cells. The effect of in vitro incubation of responder spleen cells for four days with soluble antigen was to reverse this difference. Those spleen cells exhibiting lowered plaque forming cell numbers initially (i.e. those cells from mice immunized with antigen on syngeneic or F₁ cell surfaces) showed, after incubation, a response equal to or greater than those cells which intially (before in vitro incubation) demonstrated a larger response (i.e. cells from those mice immunized with antigen on allogeneic cell surfaces).Science, Faculty ofMicrobiology and Immunology, Department ofGraduat