Tumor Cell Clone Expressing the Membrane-bound Form of IL-12p35 Subunit Stimulates Antitumor Immune Responses Dominated by CD8+ T Cells.
- Author:
Hoyong LIM
1
;
Seon Ah DO
;
Sang Min PARK
;
Young Sang KIM
Author Information
- Publication Type:In Vitro ; Original Article
- Keywords: Membrane-bound form; Interleukin-12; p35 subunit; p40 subunit; MethA fibrosarcoma
- MeSH: Animals; Antigen-Presenting Cells; Clone Cells; Corynebacterium; Fibrosarcoma; Interleukin-12; Interleukin-12 Subunit p35; Interleukin-12 Subunit p40; Macrophages; Mice; Rejection (Psychology); T-Lymphocytes; T-Lymphocytes, Helper-Inducer; Tumor Necrosis Factor-alpha
- From:Immune Network 2013;13(2):63-69
- CountryRepublic of Korea
- Language:English
- Abstract: IL-12 is a secretory heterodimeric cytokine composed of p35 and p40 subunits. IL-12 p35 and p40 subunits are sometimes produced as monomers or homodimers. IL-12 is also produced as a membrane-bound form in some cases. In this study, we hypothesized that the membrane-bound form of IL-12 subunits may function as a costimulatory signal for selective activation of TAA-specific CTL through direct priming without involving antigen presenting cells and helper T cells. MethA fibrosarcoma cells were transfected with expression vectors of membrane-bound form of IL-12p35 (mbIL-12p35) or IL-12p40 subunit (mbIL-12p40) and were selected under G418-containing medium. The tumor cell clones were analyzed for the expression of mbIL-12p35 or p40 subunit and for their stimulatory effects on macrophages. The responsible T-cell subpopulation for antitumor activity of mbIL-12p35 expressing tumor clone was also analyzed in T cell subset-depleted mice. Expression of transfected membrane-bound form of IL-12 subunits was stable during more than 3 months of in vitro culture, and the chimeric molecules were not released into culture supernatants. Neither the mbIL-12p35-expressing tumor clones nor mbIL-12p40-expressing tumor clones activated macrophages to secrete TNF-alpha. Growth of mbIL-12p35-expressing tumor clones was more accelerated in the CD8+ T cell-depleted mice than in CD4+ T cell-depleted or normal mice. These results suggest that CD8+ T cells could be responsible for the rejection of mbIL-12p35-expressing tumor clone, which may bypass activation of antigen presenting cells and CD4+ helper T cells.
