Priming of CD8+ CTL effector cells in mice by immunization with a stress protein-influenza virus nucleoprotein fusion molecule.
Literature is accumulating which suggests the potential for stress proteins to form the basis of a novel vaccine technology. Immunization with mammalian tumor-derived stress proteins and their associated peptides promote anti-tumor immunity. Vaccination with HIV-1 p24 antigen fused to mycobacterial heat shock protein (Hsp) Hsp71 enhances p24-specific immunity, as measured by p24-specific antibody production and in vitro cell proliferation and cytokine induction. An ovalbumin-Hsp71 fusion protein primes ovalbumin-specific CTL activity and resistance to challenge with an ovalbumin-expressing tumor. We have extended these observations by using a mycobacterial Hsp65 fusion molecule to prime CTL specific for a viral antigen. Gene fusion constructs were generated from DNA encoding Mycobacterium bovis strain BCG Hsp65 and individual fragments of influenza virus nucleoprotein (NP) encompassing H-2Kd- and H-2Db-restricted CTL epitopes. The ability of these purified recombinant fusion proteins to prime NP-specific CTL was assessed in mice of appropriate H-2 haplotypes. We observed that adjuvant-free immunization with either fusion protein elicited significant CTL activity when administered at doses of 10-100 micrograms per mouse. An NP fusion protein made with glutathione-S-transferase failed to elicit NP-specific CTL, indicating that the phenomenon requires Hsp65 sequences. A single immunization with the Hsp65-NP fusion protein elicited CTL activity which persisted for a minimum of 4 months post-immunization, at which time it could be boosted by a second immunization. To our knowledge, this is the first report of a member of the Hsp60 family priming for antigen-specific CTL activity when employed as a fusion protein partner.
Anthony
L S
LS
StressGen Biotechnologies Corporation, Victoria, BC, Canada. lanthony@stressgen.com
Wu
H
H
Sweet
H
H
Turnnir
C
C
Boux
L J
LJ
Mizzen
L A
LA
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D006360:Heat-Shock Proteins / Q000276:immunology*; D007114:Immunization; D016130:Immunophenotyping; D051379:Mice; D008810:Mice, Inbred C57BL; D009698:Nucleoproteins / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014760:Viral Fusion Proteins / Q000276:immunology*