Naslov
Heat shock fusion protein gp96-Ig induces activation of innate and adaptive immunity

Autori
Štrbo, Nataša ; Yamazaki, Koichi ; Sotošek, Vlatka ; Rukavina, Daniel ; Podack, Eckhard R.

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Croatian Immunological Society Annual meeting 2002 : Abstract book / - Zagreb : Hrvatsko imunološko društvo, 2002, 13-13

Skup
Croatian Immunological Society Annual meeting

Mjesto i datum
Trakošćan, Hrvatska, 22.11.2002. - 24.11.2002

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
NK cells; dendritic cells; gp96; CD91; perforin; heat shock proteins

Sažetak
Heat shock proteins (HSPs) are cellular chaperones, participating in protein synthesis and transport through the various cellular compartments. HSPs are potent activators of cellular immune response. It is known that purified from chemically induced tumors, HSPs efficiently function as tumor vaccines, causing complete tumor regressions in in vivo tumor challenge protocols. CD8 CTL and NK cells are critical effector cells for tumor rejection. As we have shown previously, gp96-Ig peptide complexes secreted by an ovalbumin transfected tumor (EG7) mediate strong, specific tumor immunity through a CD4 T cell independent CD8 CTL response. In this study, we set out to develop an in vivo system to quantitavely determine the CD8 CTL and NK response to gp96-Ig and to evaluate the molecular components (perforin, FasL) influencing CD8 CTL expansion. Secreted heat shock protein gp96-Ig was constructed by replacment of endoplasmic reticulum retention signal with Fc potion of IgG1, transfected into EG7 (EG7-gp96-Ig) and used to induce CD8+CTL expansion in vivo. Adoptively transferred, ovalbumin specific T-cell receptor (TCR) transgenic CD8+ cells (OT1) responded with clonal expansion to the immunization with EG7-gp96-Ig. OT1 expansion was quantitated with Kb-SIINFEKL tetramer by flow cytometry. We used secreted forms of gp96: gp96-Ig and gp96-myc, transfected into syngeneic or allogeneic ovalabumine expressing tumor cells to measure CD8 CTL, NK, NKT and dendritic cells (DC) activation in vivo by 4 color flow cytometry and ELISPOT and in vitro by proliferation assay. In response to primary immunization with EG7-gp96-Ig, OT1 expand in wild type mice (C57Bl/6) from initial frequency of 0.5% to 25% of all CD8 cells, and to 50% of all CD8 after a booster immunization. Endogenous ovalbumin specific CD8 cells also expand strongly. In additon to CTL, NK cells and DC expanded to gp96-Ig secretion. In perforin deficient mice (PKO), CD8+CTL and NK expansion by tumor secreted gp96-Ig was completly abolished. Adoptive transfer of wild type splenocytes or NK cells restored the ability of PKO mice to respond to secreted gp96-Ig. Since gp96 binds to CD91 on DC our data support a positive, perforin dependent feedback loop between NK and DC as being necessary for NK and CTL activation by screted gp96-Ig in vivo. This study uncovers a novel link between the innate and adaptive immune system dependent on the presence of perforin involving CD8, NK and DC.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

POVEZANOST RADA