Effect of phytohemagglutinin on thymidine incorporation and antibody production in the secondary response in vitro towards a defined hapten

Abstract

The Weizmann Institute of Science, RehovotRabbits were immunized with 2,4-dinitrophenyl bovine serum albumin (DNP-BSA), and the spleen cells were removed and cultured in uitro in the presence of either phytohemagglutinin (PHA) or antigen, or both stimulants.PHA and antigen, when reacted together, had an additive stimulatory effect on thymidine uptake and an inhibitory effect on the production of antibodies as compared to the effect of the antigen alone. Cultures treated with PHA alone contained more antibodies than unstimulated cultures.

Quantitative studies on antigenic recognition. III. Nonspecific inhibition of the recognition process

“…This would indicate that comparatively few receptors exiRed on these aggressor cell populations. There is an appreciable amount of experimental evidence to show that these receptors or recognition structures are of immunoglobulin nature [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Since recent experiments by Paul et al [26] have shown that the hinge region of IgM is cleaved by trypsin, it is not unlikely that cellular receptors subjected to similar conditions might be inactivated by this mechanism.…”