Plaque‐forming cell response in rats receiving mycobacterial adjuvant on day zero and SRBC on day four

Adjuvant disease was induced in Holtzman and Sprague-Dawley rats with intracutaneous tail injections of Mycobacterium butyricum in oil on Day 0. Four days later, sheep red blood cells (SRBC) were administered intravenously. On Day 8, presence of specific antibody-producing cells from the excised spleens was demonstrated by the plaque-forming cell (PFC) technic. A total of 63 rats was studied in three separate plaquing experiments. There was an increase in PFC response in rats given M butyricum in oil over that observed in Control groups receiving SRBC only. Challenge with SRBC accelerated the onset and intensified subsequent joint inflammation in two of three experiments. Results were significant at the 95% confidence limit. These data support the suggestions of other investigators that adjuvant disease may mirror a hyperimmune state.