Design and antitumor effect of nitrated T helper cell epitope vaccine CD47-NitraTh

Using the genetic code extension technology, the immunogenic amino acid, p-nitrophenylalanine, was introduced into the universal T cell epitope and then fused with the fragment of the extracellular region of the immune checkpoint molecular CD47(19-140)to construct a vaccine targeting CD47. The CD47-NitraTh vaccine elicited high titer antibody in BALB/c mice, significantly inhibited CT26 colon cancer cells growth, and increased the ratio of spleen CD4⁺ T cells and CD8⁺ T cells. Meanwhile, it promoted the polarization of naï ve T cells to Th1 cells. Notably, CD47-NitraTh not only increased the proportion of tumour-infiltrating lymphocytes but also reduced the proportion of Treg cells in tumour tissues, which means that CD47-NitraTh vaccine can remodel the tumour immunosuppressive microenvironment. The results of this study suggested that CD47-NitraTh can be used as an effective tumour vaccine candidate.