Rabbit serum IgG titers specific to MBP-Int280 prior to immunization (day 0), following prime (day 14) and boost (day 28) immunizations with RDEC-1Δeae860-939, and after RDEC-H19A challenge (day 35). Bars designate standard errors. *, statistically significant difference between the nonimmunized, challenged group and the immunized, challenged group.