Serum reactivities with neg Ag at several time points (I to IV). A: Group 1 comprises animals (n = 13) that were immunised with MSG1 prior to infection with M. suis and splenectomy. Pigs in group 2 (n = 10) were splenectomised and infected with M. suis. B: Occurrence of autoreactive antibodies over the time course of infection; mean values for each group are shown. Bars indicate standard errors of the means.