Rabbits were immunized to two antigens and 18-55 days later exchange transfusion was performed using blood of rabbits immunized to one antigen only. By this means, serum antibody levels to one antigen were reduced 50-84% while maintaining serum antibody levels to the second antigen. After exchange, serum antibody levels of the removed antibody rose rapidly for 24-48 hr and then more slowly, rea...

Neutralizing activity against T2 bacteriophage appeared in cultures of lymph node cells from normal rats in response to their in vitro stimulation with a cell-free filtrate derived from homogenized rat macrophages which had been incubated with T2 bacteriophage. This activity was specifically directed against T2 bacteriophage. It resided in a fraction of the culture fluid which had the salting-o...

In 1909, Theobald Smith (1) showed that injection of partially neutralized diphtheria toxin-antitoxin mixtures induced antitoxin formation in experimental animals, but that immunity did not result from mixtures containing a sufficient excess of antitoxin. These observations were subsequently confirmed (2-6) and have been extended to the study of additional antigens, such as tetanus toxoid (7-10...

Experiments were conducted to compare clostridial antibody response of beef heifers that do and do not develop injection-site lesions, evaluate long-term antibody response of a single- and multiple-dose toxoid, and evaluate the ability of a clostridial toxoid to elicit an active antibody response in newborn calves. In Exp. 1, 37 weaned heifers were vaccinated (d 0) with a clostridial vaccine (A...

In this observational study, mumps-specific in vitro lymphoproliferation was measured in 24 subjects with low antibody titers and 24 subjects with high antibody titers who received their last vaccine dose up to 16 years previously. Overall, a significant lymphoproliferative response was found in 32 subjects (66.7%)-namely, in 13 (54.2%) of those with low antibody titers and 19 (79.2%) of those ...