Role of macrophage-myelin basic protein interaction in the induction of experimental allergic encephalomyelitis in Lewis rats.

Stimulated peritoneal exudate cells (PEC) containing activated macrophages (M phi) of Lewis (Le) rats were exposed for 1 hr in vivo or in vitro to radioiodinated soluble myelin basic protein (MBP) or MBP incorporated into magnetic microspheres (MBP-microspheres). The uptake by M phi of the dose of microsphere-bound MBP averaged 6.2%, whereas the average uptake of soluble MBP was 0.17%. Naive rats were sensitized with M phi-associated MBP or M phi-associated MBP-microspheres via the hind footpads without the aid of conventional immunologic adjuvants. Draining lymph node cells (LNC) or spleen cells from sensitized rats were cultured for 3 days with guinea pig MBP (GPMBP) alone or in combination with concanavalin A (Con A), then injected i.v. into naive recipients. Clinical signs of experimental allergic encephalomyelitis (EAE) appeared 6 days after transfer of LNC or spleen cells, and typical CNS lesions were seen in recipients sacrificed 10 to 14 days after transfer. The challenge of MO-MBP-sensitized rats with MBP-CFA resulted in severe clinical signs of EAE marked by an accelerated onset of neurologic symptoms.