Suppression of the response to murine alloantigens: four-cell-type clusters, function-flipping and idiosyncratic...

Specific immune suppression develops under certain well-defined conditions of exposure to antigen, where it is evident as a diminution of the immune response due to the activity of antigen-specific suppressor cells, usually T cells. Although subject to intensive study over the last two decades, interest in suppression has declined recently because of failure to make progress in defining molecular mechanisms or the precise cells involved. This review outlines present information, and then goes on to present three new ideas that emerge from study of murine alloantigens: (1) how the formation of four-cell-type clusters might mediate suppression; (2) a classification of means whereby class II MHC molecules may mediate suppression that includes a suggestion to account for the anomalous behaviour of H-2Ab; and (3) the value of idiosyncratic responses as probes of suppressor mechanisms. It does not provide an exhaustive coverage review of the literature, but recommends certain other reviews that do so.