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.
Department of Molecular Biology, Massachusetts General Hospital, Boston 02114.
Z R
ZR
Liu
K P
KP
Williams
Y H
YH
Chang
J A
JA
Smith
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