Specific blocking in vitro of antibody synthesis by affinity labelling reagents [20]

INDUCTION of an antibody response is thought to involve an initial phase of antigen recognition by cells, but it is not yet known whether the recognizing cell is the precursor of the antibody producing cell or a distinct antigen sensitive cell¹. In any case, recognition is believed to take place through a cell-surface receptor. This was suggested from experiments in which free haptens inhibited the immunogenic effect of hapten-protein conjugates. Furthermore, closely related haptens interfered with the response induced by the hapten-protein conjugate; the antibodies inhibited were those which cross-reacted with the related haptenic determinant². Studies to characterize such a cell receptor indicated that antibodies inhibit induction of a response, possibly by competing with the receptor for the antigen², which suggested that the receptor is an antibody-like entity. The idea that antibody-like molecules are present on the membrane of the lymphoid cell is supported by observations that antibodies to immunoglobulins induce transformation in lymphoid cells³.