The relationship between immune rosette forming cells and plaque forming cells in the lizard, Calotes versicolor

The specificity of immune rosette forming cells was assessed using the in vitro blocking of rosette formation with sonicated erythrocyte fragments. An appreciable degree of inhibition of rosette formation against appropriate erythrocytes was observed. The ability of immune rosette forming cells to form plaques was analyzed by separation rating immune rosettes on a fetal calf serum (FCS) gradient or by separating immune spleen cells on Ficoll-isopyenic gradient. The majority of rosette forming cells were found in a fraction different from that of plaque forming cells. We confirmed these results using a rosette-plaque assay. The data indicate that the majority of antigen-binding cells do not secrete antibody at the peak of immune response.