Melanoma cells transfected to express CD83 induce antitumor immunity that can be increased by also engaging CD137

AUTOR(ES)
FONTE

National Academy of Sciences

RESUMO

Interactions between CD83 and its ligand(s) can up-regulate immune responses. M2-CD83 cells, derived by transfecting the M2 clone of mouse melanoma K1735 cells to express mouse CD83, were rejected by syngeneic mice, unless they were injected with a CD83Ig fusion protein. Rejection was mediated by CD4+ and CD8+ T cells plus natural killer cells, whereas rejection of M2-1D8 cells, which express anti-CD137 single-chain variable region fragments (scFv), occurs in the absence of CD8+ T cells. Furthermore, the tumor specificity of the immunity induced by the two cell lines differed. Immunization with live or mitomycin C-treated M2-CD83 cells prevented outgrowth of transplanted M2-WT cells and had therapeutic efficacy against established M2-WT tumors. A highly metastatic clone of K1735 cells, SW1-C, and its subline SW1-P2, which expresses an activating transcription factor 2-driven peptide, were then studied because they have particularly low immunogenicity. Neither SW1-C nor SW1-P2 cells became rejectable after expression of CD83 or anti-CD137 scFv. However, outgrowth of cells from either line was delayed in mice immunized against M2-CD83 or M2-1D8 cells, and immunization with a mixture of mitomycin C-treated cells from M2-CD83 plus M2-1D8 prevented tumor formation by SW1-P2 cells in five of five and by SW1-C cells in three of five mice. We conclude that M2 cells expressing CD83 can induce a tumor-destructive immune response also against SW1 cells and that this response can be made more effective by combining them with M2 cells expressing anti-CD137 scFv. A similar approach may be therapeutically beneficial against certain human cancers.

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