In vivo selection of a lymphocytic choriomeningitis virus variant that affects recognition of the GP33-43 epitope by H-2Db but not H-2Kb.

An escape mutant encoding the V3A substitution was obtained and the variant peptide is studied for MHC binding. Native epitope sequence in all databases has a C in position 9. Artificial peptide with M at position 9 is used in this MHC binding assay. The effect of the V3A substitution on Kb binding (from 7 to 20 nM IC50) is much less dramatic than the effect on Db binding (from 21 to 329 nM IC50).