The effect of antigen dosage on the response of adoptively transferred cells.

Mice were immunized with BSA or HSA in Freund's adjuvant, and their lymph node and spleen cells transplanted into syngeneic hosts, which in most experiments had been irradiated. After transplantation the cells do not synthesize much antibody if left without stimulation, but can be stimulated to do so by injection of BSA or HSA in solution. The response has been studied over a dose range of 10–10 μg. antigen. Stimulation can be detected down to 10 μg. antigen, and reaches a maximum at middling doses. Middling doses stimulate proliferation of the primed cells to an extent which can be measured by IUdR uptake. At high doses both antibody production and IUdR uptake are inhibited. The conclusion is drawn that high concentrations of antigen can paralyse the immunological reaction of primed cells.