Interleukin-6 promotes anti-OspA borreliacidal antibody production in vitro

Determination of the immunological mediators responsible for promoting the production of borreliacidal antibody may facilitate the development of an improved borreliosis vaccine for human and veterinary use. Previously, we developed an in vitro assay to determine if borreliacidal antibody production could be augmented by treatment with different cytokines. In this study, in vitro treatment of lymph node cells producing borreliacidal antibody with recombinant interleukin-6 (rIL-6) resulted in a fourfold enhancement of anti-OspA borreliacidal antibody. Moreover, rIL-6 enhanced Western immunoblot titers and increased the number of B lymphocytes. In contrast, treatment of anti-OspA borreliacidal antibody-producing cells with anti-IL-6 resulted in a fourfold reduction in borreliacidal activity. Treatment with anti-IL-6 also inhibited enhanced borreliacidal antibody production induced by anti-gamma interferon. These data suggest that IL-6 plays a significant role in the production of anti-OspA borreliacidal antibodies.