Prevention of experimental allergic neuritis in the Lewis rat with bovine P2 protein

Protective doses of bovine P2 protein (5, 15 or 50 micrograms) in incomplete Freund's adjuvant (IFA) were administered to Lewis rats and were followed 2, 4 or 10 weeks later by challenging doses of either 250 micrograms bovine P2 or 2.5 mg bovine PNS myelin in complete Freund's adjuvant (CFA). Protection from experimental allergic neuritis (EAN) could be achieved with a single dose of 5 micrograms of P2 in IFA. There was little difference between prophylactic 5 micrograms and 15 micrograms doses of P2. The degree of protection depended upon the interval between protective innoculation and challenge. Protection was partial at 2 weeks and maximal at 4 weeks at which time there was complete protection against P2-induced EAN and less complete protection from myelin-induced disease. Complete protection at 4 weeks from myelin-induced EAN was achieved with a 50 micrograms dose. Protection lasted for at least 10 weeks (the longest interval assessed) and was complete with respect to P2-induced EAN. Partial protection was observed in myelin-challenged animals after 10 weeks with the level of protection greater than that observed after 2 weeks.