However, at 3 weeks post-infection, the level of IgG2a in AQP4 KO mice was significantly lower than that in WT mice (Figure 8B), while at 5 weeks post-infection, a markedly higher level of IgG1 was observed in AQP4 KO mice compared with that in WT mice (Figure 8C). Here, AQP4 is linked to infection.