Immunogenicity of synthetic peptide sequences S81 and S82 (residues 68-83 and 65-83) of bovine myelin basic protein. Time-course of antibody responses in rats and rabbits.

The timing and intensity of the antibody responses to the marker determinants of synthetic peptide S81 and S82 sequences of bovine myelin basic protein (MBP) (residues 68-83 and 65-83, respectively) were studied in 20 Lewis rats and 6 rabbits. All rats immunized with either peptide in CFA responded with antibody development. All rabbits immunized with S82 and CFA developed both antibodies and experimental allergic encephalomyelitis. In contrast only one rabbit developed antibodies against S81 and none of the S81-challenged rabbits developed disease. On the basis of extrapolation of linear time-response curves to zero activity, the time of appearance of anti-peptide antibody activity in the Lewis rats was 15.1 +/- 1.7 days after a single immunization, a week longer than the normal latent period before appearance of anti-MBP antibodies. The time of appearance of anti-S82 antibody activity in rabbits exhibiting linear response curves was 18 days, 4 days after a booster immunization with S82 in incomplete Freund's adjuvant. The development of clinical signs of experimental allergic encephalomyelitis occurred within 4 weeks after initial challenge (a few days after boosting) and continued for 8--13 days in all S82-immunized rabbits.