The possibility that a rat alloantiserum DA anti-Lewis possesses similar recognition structures for Lewis transplantation antigens, as do DA immunocompetent cells, was investigated by raising an antiserum against this alloantiserum in (Lewis x DA)F1 hosts. This antiserum, as well as one provoked by injecting DA lymphoid cells, was active against recognition structures for Lewis antigens of DA immunocompetent cells. The anti-(DA anti-Lewis) antiserum displayed the same degree of specificity as was found previously for anti-recognition structure sera prepared by injecting parental strain lymphoid cells into F1 hosts. Since the activities of antisera raised against cell-bound receptors or against the antigen-binding region of an immunoglobulin were indistinguishable, it was concluded that the functional part of cell-associated receptors might be structurally similar to the variable portion of an immunoglobulin.
CELLULAR RECEPTORS