Antitumor effects of a tumor cell vaccine expressing a membrane-bound form of the IL-12 p35 subunit.
We investigated whether expression of the IL-12 p35 subunit in membrane-bound form in tumor cells enhanced their immunogenicity. Since p35 is only secreted when associated with the IL-12 p40 subunit, we generated tumor cells expressing membrane-bound forms of p35 and p40 as chimeras with the transmembrane/cytoplasmic region of TNFα (mbIL-12p35 and mbIL-12p40). The relevant vectors were transfected into MethA fibrosarcoma cells, and mbIL-12p35 or mbIL-12p40-expressing tumor clones were isolated and their ability to induce antitumor immunity studied. Cells of the mbIL-12p35 tumor clone induced CD69 expression and IFNγ production in purified CD8(+) T cells in vitro, and their in vivo tumorigenicity was reduced. Cells of the mbIL-12p40 tumor clone failed to show either of these activities. Mice that had rejected cells of the mbIL-12p35 tumor clone possessed systemic antitumor immunity to wild type tumor cells. The growth rate of mbIL-12p35 tumor cells was greater in CD8(+) T cell-depleted mice than in CD4(+) T-cell- and NK cell-depleted mice or normal mice, suggesting that CD8(+) T cells were mainly responsible for the antitumor immunity. These results indicate that expression of mbIL-12p35 on tumor cells enhances their immunogenicity by increasing their ability to activate CD8(+) T cells, possibly by direct priming.
Lim
Ho Yong
HY
Department of Biochemistry, Chungnam National University, Daejeon, Republic of Korea.
Ju
Hee Young
HY
Chung
Hee-Yong
HY
Kim
Young Sang
YS
D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000235:genetics / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology*; D045744:Cell Line, Tumor; D005354:Fibrosarcoma / Q000276:immunology*; D005434:Flow Cytometry; D005818:Genetic Engineering; D007371:Interferon-gamma / Q000235:genetics / Q000378:metabolism; D053765:Interleukin-12 Subunit p35 / Q000235:genetics / Q000276:immunology*; D053762:Interleukin-12 Subunit p40 / Q000235:genetics / Q000276:immunology; D037181:Lectins, C-Type / Q000235:genetics / Q000378:metabolism; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D000099192:CD69 Antigens
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D019496:Cancer Vaccines; D007371:Interferon-gamma; D053765:Interleukin-12 Subunit p35; D053762:Interleukin-12 Subunit p40; D037181:Lectins, C-Type; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; D000099192:CD69 Antigens