Selectin of encephalitogenic rat T‐Lymphocyte clones recognizing an immunodominant epitope on myelin basic protein

Using the soft agar‐cloning technique, we isolated 13 T‐cell clones from guinea pig basic protein (GP‐BP)‐specific T‐cell lines derived from Lewis rats. The clonal frequency was approximately 2.5 × 10⁻⁵. Each of these clones had a similar but not identical pattern of response to a battery of synthetic peptides representing overlapping epitopes in the encephalitogenic region for Lewis rats (69–89 sequence). All clones responded to the minimal encephalitogenic sequence (residues 72–84) restricted by I‐A but not I‐E molecules, and all transferred clinical experimental autoimmune encephalomyelitis (EAE) and delayed‐type hypersensitivity (DTH) reaction to naive rats. Phenotypically, the clones were W3/13⁺ (total T), W3/25⁺ (T helper), and OX‐22⁺ (DTH associated). This report demonstrates for the first time the applicability of the soft agar‐cloning technique for obtaining encephalitogenic T‐cell clones. The exclusive recovery of 72–84‐specific T‐cell clones after only two rounds of stimulation with GP‐BP indicates the immunodominance of this epitope and the power of the line selection technique for obtaining encephalitogenic T‐cell specificities.