Crossrecognition by CD8 T cell receptor alpha beta cytotoxic T lymphocytes of peptides in the self and the mycobacterial hsp60 which share intermediate sequence homology.
Immunization of C57BL/6 mice with the mycobacterial heat shock protein (hsp) 60 in immunostimulating complexes caused the in vivo activation of autoreactive major histocompatibility complex class I (H-2Db)-restricted CD8 T cell receptor (TcR) alpha/beta cells. A CD8 TcR alpha/beta clone with specificity for the mycobacterial hsp60 peptide499-508 was derived from this immunization, which, in addition, recognized syngeneic macrophages which had been stressed by interferon-gamma (IFN-gamma) stimulation. The stress-induced, self peptide could be extracted from IFN-gamma-stressed macrophages by acid elution, suggesting that the IFN-gamma-induced self peptide is derived from an endogenous protein. Based on our observation that lysis of stressed target cells by this cytotoxic T lymphocyte (CTL) clone was specifically inhibited by hsp60-specific antisense oligonucleotides, we used synthetic peptides representing amino acid (aa) sequences of the murine hsp60 for target cell sensitization and identification of the relevant self peptide. Synthetic peptides representing 9-mer to 11-mer aa sequences of the murine hsp60 with asparagine in anchor position 4 or 5 as the minimal requirement for H-2Db binding were tested in CTL assays. The overlapping murine hsp60 peptides162-170/171 were stimulatory at a concentration as low as 10-100 pM. Seven other peptides of the murine hsp60 required intermediate peptide concentrations of 10-100 nM for recognition by the CTL clone. Although the murine and mycobacterial hsp60 peptides recognized by this CTL clone showed only intermediate homology (3 identical and 3 similar aa), our data suggest that endogenous hsp60 itself is the source of self peptide(s) presented by IFN-gamma-stressed macrophages to the cross-reactive CTL clone with promiscuous specificity. This notion is consistent with the idea of hsp as a link between infection and autoimmunity.
Zügel
U
U
Department of Immunology, University of Ulm, FRG.
Schoel
B
B
Yamamoto
S
S
Hengel
H
H
Morein
B
B
Kaufmann
S H
SH
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000276:immunology*; D001483:Base Sequence; D018834:Chaperonin 60 / Q000737:chemistry / Q000276:immunology*; D003429:Cross Reactions; D005260:Female; D016882:ISCOMs / Q000276:immunology; D007371:Interferon-gamma / Q000494:pharmacology; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009161:Mycobacterium / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis*; D017386:Sequence Homology, Amino Acid; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D001426:Bacterial Proteins; D018834:Chaperonin 60; D016882:ISCOMs; D010446:Peptide Fragments; D016693:Receptors, Antigen, T-Cell, alpha-beta; D007371:Interferon-gamma