The effect of co-expression costimulatory molecule CD80 on uptake of antigen peptide-MHC class I-GFP complex by specific T cells

Abstract

CD80, a costimulatory molecule, plays an important role in eliciting antitumor immunity. Without costimulation, recognition of antigens by T cells may not cause a response, even if tumor cells express MHC class I molecules and specific antigens. On the basis of the recombinant GFP-tagged K b molecule, we constructed a co-expression vector of CD80 and GFP-tagged K b molecules. The recombinant fusion was transfected into mouse melanoma B16 cells by electroporation; positive cells were obtained by G418 screening. Highly expressing monoclonal cells, irradiated by 137 Cs, were used to immunize mice to obtain specific T cells, which were then cultivated with tumor cells in vitro and examined with a laser confocal microscope. The evident and intense uptake of the antigen peptide-MHC class I-GFP complex by specific T cells was visualized from the culture of B16/CD80-K b-GFP and T cells. However, little uptake was observed from the culture of B16/K b-GFP and T cells. These results show that co-expression of CD80 molecules with K b , an MHC class I molecule, on the surface of B16 tumor cells can enhance the response of specific T cells and thus increase the uptake of the antigen peptide-MHC class I-GFP complex. The absorbed green fluorescence was concentrated mainly on the T cell surface, and this result might pave the way to eluting specific antigen peptides directly from T cells to find and isolate novel tumor-specific antigen peptides.

A study on anti-tumor immunity induced by gene-modified melanoma B16 cells

“…In addition, a mechanism that prevents antigen-specific T cells from activation and causing local immunity tolerance in the tumor microenvironment is the low expression of the costimulatory molecule on the tumor cell surface (17,18). CD80, as a costimulatory molecule, plays an important role in T cell activation (8). The role of cytokines in T cell activation is also vital.…”

“…Without a costimulatory signal, T cells cannot be activated thoroughly and can even be in an anergy condition (6,7). The costimulatory molecule, CD80, plays an important role in the process of T cell activation (8). In addition, the lack of cytokines is one of the reasons for the tumor's escape from the immune system.…”

Co-expression of P1A35-43/β2m fusion protein and co-stimulatory molecule CD80 elicits effective anti-tumor immunity in the P815 mouse mastocytoma tumor model

“…Different modes of immunization with these two antigens have been tested for their efficiency to induce antitumor CTL responses or antitumor protection. In this study, we show that the co-expression of the epitopelinked ß2m molecule (P1A 35-43 -linked ß2m molecule or P198 [14][15][16][17][18][19][20][21][22] -linked ß2m molecule) and the co-stimulatory molecule CD80 in P815 tumor cells could significantly decrease tumorigenicity in syngeneic DBA/2 mice. In contrast, the in vivo growth of P815 cells expressing both the P1A 35-43 -linked ß2m molecule and CD80 is slower than that of P815 cells expressing both the P198 14-22 -linked ß2m molecule and CD80.…”

“…The plasmids, pcDNA3/P1A and pcDNA3/P198, are the eukaryotic expression vectors pcDNA3 (Invitrogen, CA, USA) containing the human ß2m leader followed by either the P1A [35][36][37][38][39][40][41][42][43] or P198 [14][15][16][17][18][19][20][21][22] peptide epitope tethered to the ß2m through an 8-amino acid (8aa) linker [(GGGS) 2 ]. The constructs were generated using a template from a similar construct, the human ß2m leader-OVA 258-265 -8aa linker-hß2m, inserted as a HindIII/XbaI fragment in pcDNA3 (12).…”

“…CD80 plays an important role in the activation of T cells, exogenous costimulatory molecules in tumor cells can lead to the strengthening of the effects of T cells, including cell proliferation, secretion of cytokine and CTL activity (16,17). We have successfully constructed a coexpression vector of CD80 and GFP-tagged K b molecules to enhance the response of specific T cells and thus increase the uptake of the antigen peptide-MHC class I-GFP complex (18). Therefore, we also examined the role of CD80, a member of the B7 family, in the T-cell response induced by genetically engineered P815 cells.…”