Depression of direct plaque-forming cell response in mouse spleen cell cultures by aggregated IgG2b-induced factors

Abstract

Mouse spleen cells were treated with concanavalin A (Con A) or aggregated mouse IgG2b for 48 h in culture. When cells thus treated were added to fresh mouse spleen cell cultures immunized with SRBC they depressed the response of B lymphocytes as measured by enumerating plaque forming cells (PFC) on the fourth day of culture. When supernatant from cells cultured with IgG2b was added to immunized cultures this resulted in depression of PFC generation similar to that observed by addition of treated cells. The depression observed was essentially in the same range as that observed by addition of Con A treated cells or their supernatant. These observations extend previous work suggesting that IgG2b-induced PFC depression may result from activation of suppressor T cells with elaboration of soluble suppressor factors. This mechanism of immunomodulation may be important in the pathogenesis of immune complex disorders.