Cell-mediated immune response to guinea pig and bovine basic proteins of myelin in Lewis and PVG rats and their hybrids.

The in vitro cell-mediated immune response of rat lymph node cells (LNC) to guinea pig and bovine encephalitogenic protein (EP) has been studied with a LNC transformation test. LNC were obtained from either Lewis, PVG, or F1 (Lewis x PVG) rats 28 days after challenge with guinea pig or bovine EP in Freund's complete adjuvant (FCA) of different mycobacterium content. No differences between the strains or their hybrids in LNC response could be shown if stimulated with sensitizing EP, despite the great differences in capacity for disease development in those animals. Nor did a fivefold lowering of the amount of mycobacterium content in FCA, when guinea pig EP was used at challenge, lessen the in vitro response, although this reduces the disease development. Sensitization with guinea pig EP causes an in vitro cross-reactivity to bovine EP and the reciprocal cross-reactivity probably also exists. In rabbits, this cross-reactivity in both directions was clear-cut. LNC from Lewis rats challenged with guinea pig EP in FAC, with the higher amount of mycobacterium, showed in vitro responses to tested peptides of this EP; the amino acid sequences of these were: 1-42, 43-88, 89-169, and HNB-89-169 (89-169 blocked at the tryptophan-residue by hydroxynitrobenzylation).