The structural variations that distinguish the A molecules encoded by wild-derived H-2 complexes which express A(k)-related molecules have been localized into the α1 and β1 domains by radiochemical sequence analyses of tryptic peptides. The A(α) subunits of B10.STC90 (A(kv1)) and W12A (A(kv2)) differ from those of B10.BR (A(k)) in two adjacent tryptic peptides spanning positions 43 to 71 in the α1 domain. The A(β) subunit of W12A differs from that of B10.BR in two peptides spanning positions 26 to 29 and 95 to 106. Isoleucine and leucine residues present at positions 28 and 95, respectively, in the B10.BR A(β) subunit are not found in the corresponding positions in W12A A(β) subunits. Both of these A(β) sequence variations are in the β1 domain. B10.STC90 A(β) subunits are identical to those of W12A except for a structural variation in the β1 domain affecting the HPLC retention time of a peptide spanning positions 49 to 63. These results suggest that these A molecules are encoded by closely related class II gene alleles which have diversified by the accumulation of discrete mutations within the exons encoding the α1 and β1 domains of the A molecule. Our previous functional analyses of these minor variant A molecules have demonstrated that they are readily distinguished with A molecule-specific alloreactive T lymphocytes. Together, these findings suggest that minor structural variations in the α1 and β1 domains of the A molecule can dramatically modify the allodeterminants recognized by alloreactive T lymphocytes.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Immunology|
|State||Published - Jan 1 1985|
ASJC Scopus subject areas
- Immunology and Allergy