EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS AND VACCINATION-INDUCED RESISTANCE IN DA RATS

In this report, we show that DA rats (RT1(a) haplotype) immunized with myelin basic protein (MBP)-CFA develop and recover from an ascending paralysis, with the course and severity of clinical disease similar to the kinetics observed with MBP-CFA-immunized Lewis rats. Experimental allergic encephalomyelitis (EAE) can be adoptively transferred with M BP-stimulated immune spleen cells, with onset of paralysis 4 days foll owing transfer and complete recovery 3-4 days later. To determine if t he vaccination-induced resistance response could develop in the DA rat strain, which has previously been shown to occur only in the Lewis ra t, we selected a RSBP-specific T-cell line by standard methods from DA rats immunized previously with MBP-CFA. The DA T-cell line was enceph alitogenic, and DA recipients developed and recovered from T-cell line -mediated paralytic disease. Following recovery from T-cell line-media ted disease, DA recipients were resistant to subsequent disease induct ion following MBP-CFA challenge, a response consistent with T-cell vac cination, as observed previously in Lewis rats, Analysis of the prolif erative response of the DA T-cell line showed that the encephalitogeni c fragment was within the 40-67 region of MBP, with no response to the 85-97 fragment. The 85-97 fragment, which is a minor encephalitogenic determinant for the Lewis strain, also appears to be a minor encephal itogenic epitope for DA rats. These results show that the vaccination- induced resistance response occurs in the DA rat strain and that this phenomenon is not unique to the Lewis rat model. (C) 1997 Academic Pre ss