Rat MHC class I peptides are immunogenic.
We postulated that indirect recognition of MHC-derived peptides might modulate the alloresponse to donor antigen. In this study, we looked at the potential of two class I peptides derived from the alpha 1 and alpha 2 regions of the DA RT1Aa molecule. Lew responder rats were immunized by varying concentrations of two 25mer peptides covering residues 56-81 and 96-120. The injections were under the footpad and were repeated on day 14. The thickness of the footpads was measured to control delayed-type hypersensitivity (DTH). The animals were sacrificed on day 16 and the splenocytes were tested in mixed lymphocyte culture as responders against DA stimulator cells and CAP third-party splenocytes. In addition, the phenotype of the cells was measured using flow cytometry with antibodies against CD4, CD8, CD5, MHC class II, CD25, CD14 and CD19. Peptide 96-120 induced strong sensitization of the Lew recipient animals at concentrations of 200-500 micrograms (n = 4). The stimulation index was 2-3 times higher than that of untreated animals. Peptide 56-81 failed to induce sensitization at the concentrations used, but surprisingly induced a concentration-dependent immunosuppression that was highest at 400 micrograms (n = 4). In proliferation experiments responder Lew rats proliferated only to peptide 56-81 in vitro.
Zavazava
N
N
Institute of Immunologie, University of Kiel, Germany.
Fandrich
F
F
Ott
K A
KA
Freese
A
A
Turnewitsch
K
K
D000595:Amino Acid Sequence; D000818:Animals; D004306:Dose-Response Relationship, Immunologic; D006649:Histocompatibility Antigens / Q000276:immunology*; D006968:Hypersensitivity, Delayed; D007114:Immunization; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology*; D051381:Rats; D011917:Rats, Inbred Lew
D006649:Histocompatibility Antigens; D010446:Peptide Fragments; C038353:histocompatibility antigens RT, rat