Nanoparticle orientationally displayed antigen epitopes improve neutralizing antibody level in a model of porcine circovirus type 2

Ding, Peiyang; Zhang, Teng; Li, Yafei; Teng, Man; Sun, Yaning; Liu, Xiao; Chai, Shujun; Zhou, Enmin; Jin, Qianyue; Zhang, Gaiping

The cytokine in spleen lymphocytes supernatant was measured by ELISA after the cells were stimulated with Cap protein. IL-4 and IL-10 are the archetypal Th2 cellular immune response cytokines that improve the production of IgG1. As shown in Figure 8B and C, Cap-AuNPs induced significantly high levels of IL-4 and IL-10 production than Cap or AuNPs. IFN-γ, Th1-biased cytokine, can promote the proliferation and differentiation of T cells, stimulate the secretion of IgG2a and IgG2b, activate macrophages, and enhance the cytotoxic effect of NK cells, conferring protection against viral infection. As shown in Figure 8D , Cap-AuNPs resulted in markedly higher level of IFN-γ than either the Cap or AuNPs. Interestingly, AuNPs induced a higher level of IFN-γ than Cap. We speculate that the increase in IFN-γ secretion may be due to the initial interaction of AuNPs with NK cells after AuNPs were injected into mice. 42 In addition, it is likely that Cap protein mainly