The expression and function of surface immunoglobulin (sIg) receptors was analyzed using antigen-specific monoclonal B cells and T cells. When B cells were incubated with antigen (hapten carrier), hapten-specific sIg receptor expression was greatly reduced. The specific antigen-presentation activity of the B cells was also markedly reduced. Following the removal of antigen, expression of the sIg receptors was restored to original levels within 3-4 hr. Specific antigen-presentation activity of these B cells was concomitantly restored. Reduction of sIg receptor expression and specific antigen presentation were inhibited by the addition of competing free hapten, suggesting that crosslinking of sIg receptors is required for the observed changes in sIg receptor expression and that specific antigen presentation is hapten specific. Using oligopeptide-specific Th cells, we could show the requirement for processing of antigen in the interaction between hapten-specific B cells and carrier-specific T cells. These results indicated that the expression of sIg receptors for a specific antigen and the ability to present the antigen are interrelated.