Abrogation of induced resistance to experimental allergic encephalomyelitis in guinea pigs by host-versus-graft reaction.

Experimental allergic encephalomyelitis (EAE) effector cells known to exist in guinea pigs with myelin basic protein-incomplete Freund's adjuvant (MBP-IFA)-induced resistance to EAE could be activated in vivo by means of allogeneic confrontation (local host-versus-graft reaction (HVGR)). The abrogation of the resistance was observed only when HVGR was combined with encephalitogenic challenge (myelin basic protein-complete Freund's adjuvant (MBP-CFA)) in a certain order and at certain time intervals. The injection of 20 x 10(7) gamma-irradiated allogeneic lymphoid cells 7 or 4 days prior to or along with MBP-CFA treatment resulted in development of EAE with delayed onset and protracted course. The effect was most prominent when HVGR was induced on day -4. Histological examination revealed inflammatory lymphoid cell infiltrations in spinal cord. Serum level of total and anaphylactic anti-MBP antibodies correlated with the clinical picture.