ASSOCIATION BETWEEN POLYCLONAL B-CELL ACTIVATION AND THE PRESENCE OF AUTOANTIBODIES IN MICE INFECTED WITH YERSINIA-ENTEROCOLITICA O-3

Eight-week old conventional female Swiss mice were inoculated intraven ously with Yersinia enterocolitica O:3. A second group of normal mice was used as control. Five mice from each group were bled by heart punc ture and their spleens were removed for spleen cell collection on the 3rd, 5th, 7th, 10th, 14th and 21st day after infection, Immunoglobulin -secreting spleen cells were detected by the isotype-specific protein A plaque assay. Total immunoglobulin levels were determined in mouse s erum by single radial immunodiffusion and the presence of autoantibodi es was determined by ELISA. We observed a marked increase in the total number of cells secreting immunoglobulins of all isotypes as early as on the 3rd day post-infection and the peak of secretion occurred on t he 7th day, At the peak of the immunoglobulins response, the total num ber of secreting cells was 19 times higher than that of control mice a nd most immunoglobulin-secreting cells were of the IgG(2a) isotype. On the 10th day post-infection, total serum immunoglobulin values were 2 times higher in infected animals when compared to the control group, and continued at this level up to the 21st day post-infection. Serum a bsorption with viable Y. enterocolitica cells had little effect on ant ibody levels detected by single radial immunodiffusion, Analysis of se rum autoantibody levels revealed that Y. enterocolitica infection indu ced an increase of antimyosin and anti-myelin immunoglobulins. The se: ra did not react with collagen. The present study demonstrates that Y. enterocolitica O:3 infection induces polyclonal activation of murine B cells which is correlated with the activation of some autoreactive l ymphocyte clones.