Immune recognition of serum albumin. XVI. role of adjuvant in the autoimmune response to mouse serum albumin

Abstract

Recently, we reported an autoreactivity with rabbit serum albumin of rabbit antisera against bovine serum albumin (BSA) or human serum albumin. Also immunization of rabbits, each with its own serum albumin in complete Freund's adjuvant (CFA), gave without exception an autoantibody response to rabbit serum albumin. The effect of adjuvant in the autoimmune response was proposed and the present work has investigated this effect. Mice immunized with BSA emulsified in CFA gave a high antibody response to BSA which exhibited considerable autoreactivity with mouse serum albumin (MSA). When BSA was injected in buffered saline (PBS) at one site and CFA was injected at a different site but on the same side of the animal, a lower antibody response (to BSA) was observed and the antibodies exhibited a lower autoreactivity with MSA than when BSA-CFA emulsion was employed. No autoreactivity was observed when BSA in PBS and CFA were injected on two different sides of the animal or when BSA in PBS was injected without adjuvant. Injection of CFA alone generated no antibody response. Similar experiments were carried out in which MSA was injected in mice. Autoantibodies were obtained when MSA in CFA emulsion was injected. A marginal autoantibody response was detected when MSA in PBS and CFA were injected at different sites on the same side of the animal. All other protocols, including emulsion in incomplete Freund's adjuvant, failed to stimulate an autoantibody response. The results indicate that CFA plays a critical role in the autoimmune response and that adjuvant and antigen must act on the same lymph nodes to mount a fruitful autoimmune response.