Figure 4.

Spirulina LPS inhibits IL-17 production through TLR4 on APCs, and neutralization of endogenous IL-17 in MH134-bearing mice results in tumor regression. (A) Spleen cells from OVA-specific TCR transgenic mice were cultured with OVA in the absence (left) or presence (right) of anti-IFN-γ mAb for 5 days. Graded doses of E. coli or Spirulina LPS were further added into the culture to examine their effect on IL-17 production. Background IL-17 production without OVA was <22 pg/ml. *P<0.05 compared with control. (B) CD4 T cells from OVA-primed C3H/HeJ mice and splenic APCs from C3H/HeN or C3H/HeJ mice were co-cultured with OVA in the absence or presence of Spirulina LPS for 5 days. The culture supernatant levels of IL-17 were measured. *P<0.05 compared with no Spirulina LPS. (C) Tumor-bearing C3H/HeN mice were injected with anti-IL-17, anti-IFN-γ, or control rat IgG antibodies 1 day before and 4 days after tumor implantation. Data represent mean tumor growth ± SE of 5 mice per group. *P<0.05 compared with no Ab. (D) In the same experiment as in C, serum IFN-γ was measured (in vivo). *P<0.05 compared with Rat IgG. Spleen cells from tumor-bearing mice treated with anti-IL-17 mAb or Rat IgG as in C were prepared 24 days after tumor implantation and cultured for 4 days to measure the production of IFN-γ (in vitro). Data represent mean ± SE. *P<0.05 compared with Rat IgG.