CD4 and neoplasm: In our pre-experiments, treating 1 × 106 of SLpFlaB alone to mice did not effectively stimulate the expansion of CD4 T cells and CD8 T cells in the tumor, which is consistent with the other research results; for example, in mice treated with 1 × 107 of SLpFlaB, no expansion of CD4 T cells and CD8 T cells was detected [20].