STUDIES ON ANTIBODY PRODUCTION. XII. INHIBITION OF PRIMING BY DRUGS.

The effect of drugs upon the primary and the secondary antibody response to diphtheria toxoid in mice was studied using an experimental system previously described. Triethylenethiophosphoramide (thio-TEPA), chloramphenicol, 6-mercaptopurine, 8-azaguanine, and versenate were found to inhibit, partially or completely,"priming" for the secondary response. Thio-TEPA, chloramphenicol, and 6-mercaptopurine, in doses exceeding those effective in inhibiting priming, did not cause alteration of the secondary response when given only during the secondary response. However, when chloramphenicol and amethopterin were given for 5 days prior to and at least 5 days after the second antigen injection, slight suppression of peak secondary titers occurred. Therefore, drug dosages effective in suppressing priming had less effect on the secondary response. It thus appears that there is a real difference between "priming" and the induction of antibody synthesis.