Cell Interactions in Antibody Formation in Vitro

Abstract

Abstract Spleen cells from DBA/2J and CBA/J mice were separated into adherent and nonadherent cell populations; adherent cells obtained from either strain may be recombined with DBA nonadherent cells and the kinetics and magnitude of the plaque-forming cell response to SRBC are equivalent. An alloantiserum directed against CBA spleen cells was used to study the length of time that the adherent population was required for a maximum in vitro response. The alloantiserum abolished the response when added during the first 2 days of culture, indicating that the adherent cell was required at least during the inductive phase of the response. This was true whether adherent cells were prepared from either spleen cells or peritoneal exudate cells of CBA mice. Nonadherent cells from mice immunized 1 week earlier required the cooperative participation of adherent cells for a shorter period than nonadherent cells from normal or remotely immunized mice. This result is consistent with the idea that most of the adherent cell dependent events have occurred in the nonadherent population following exposure to antigen in vivo. The present study demonstrates that a cell type in the adherent population is an active participant in the cell interactions leading to antibody formation in both primary and secondary in vitro responses. It is proposed that the adherent cell is an “antigen-focusing” cell which functions by providing foci of increased cell density thereby promoting interactions between thymus and bone marrow-derived cells.