Single amino acid substitution alters T cell determinant selection during antigen processing of Staphylococcus aureus nuclease.
The effect of amino acid residues outside of T cell determinant regions of Staphylococcus aureus nuclease (Nase) on the activation of T cell hybridomas has been investigated. T cell hybridomas derived from BALB/c mice immunized with Nase were screened against a nested set of overlapping synthetic peptides spanning the entire Nase molecule. Five regions of Nase, encompassing residues 1 to 20, 21 to 40, 61 to 80, 101 to 120, and 112 to 130, were found to be the T cell determinants. Region 61 to 80 is the immunodominant site. Mutants of Nase with a single amino acid substitution outside the defined T cell determinants were tested for their ability to stimulate the T cell hybridomas. The substitution of arginine for glutamic acid at residue 43 markedly reduces the antigenic potency of the protein for I-Ed restricted T cell hybridomas, which recognize Nase peptides comprised of residues 21 to 40 (p21-40) or 112 to 130 (p112-130). In contrast, the stimulatory capacity of this mutant for I-Ad restricted T cell hybridomas remains unchanged. Our results suggest that selective regulation of an immune response may be achieved by appropriately mutagenizing protein Ag.
Liu
Z R
ZR
Department of Molecular Biology, Massachusetts General Hospital, Boston 02114.
Williams
K P
KP
Chang
Y H
YH
Smith
J A
JA
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology* / Q000378:metabolism*; D000939:Epitopes / Q000737:chemistry*; D000949:Histocompatibility Antigens Class II / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008836:Micrococcal Nuclease / Q000276:immunology* / Q000378:metabolism*; D010446:Peptide Fragments / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D000942:Antigens, Bacterial; D000939:Epitopes; D000949:Histocompatibility Antigens Class II; D010446:Peptide Fragments; D008836:Micrococcal Nuclease