Immunization of mice with the N-terminal (1-272) fragment of simian virus 40 large T antigen (without adjuvants) specifically primes cytotoxic T lymphocytes.
Immunization of C57BL/6 (B6) mice (H-2b) with the "large tumor antigen" (T-Ag) of simian virus 40 (SV40) in its soluble form without adjuvants primed CD8+ cytotoxic T lymphocytes (CTL) in vivo. CD8+ CTL primed in vivo by this non-structural 708-amino acid (aa) viral protein, and specifically restimulated in vitro, lysed H-2b target cells, either transfected with an SV40 T-Ag-encoding vector, or transformed by SV40 infection. H-2b RMA-S transfectants expressing the complete 708 aa T-Ag (which fail to transport peptides through the endoplasmic reticulum membranes) were not lysed. CTL were also efficiently primed in vivo by injection of the N-terminal 272 aa fragment of the T-Ag. Hence, this fragment contains the structure(s) required for a soluble protein to enter the "endogenous" class I-restricted antigen processing and presentation pathway for CD8+ CTL activation. In soluble form, the complete T-Ag or the N-terminal T-Ag fragment sensitized in vitro RBL5 cells for lysis by T-Ag-specific CTL lines and clones. This in vitro sensitization was blocked by brefeldin A. In contrast, specific recognition of RBL5 cells pulsed in vitro with synthetic, immunogenic nonapeptides (derived from N-terminal T-Ag epitopes) by CTL lines was insensitive to brefeldin A. Hence, T-Ag and its 272-aa N-terminal fragment can enter the "endogenous" processing pathway and prime CD8+ CTL in vivo and in vitro.
Schirmbeck
R
R
Institut für Mikrobiologie, Universität Ulm, FRG.
Zerrahn
J
J
Kuhröber
A
A
Deppert
W
W
Reimann
J
J
D000276:Adjuvants, Immunologic; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D000952:Antigens, Polyomavirus Transforming / Q000276:immunology*; D002460:Cell Line; D003001:Cloning, Molecular; D003602:Cytotoxicity, Immunologic; D004705:Endocytosis; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010446:Peptide Fragments / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D000276:Adjuvants, Immunologic; D000952:Antigens, Polyomavirus Transforming; D010446:Peptide Fragments; D011994:Recombinant Proteins