As the infection progresses to d28 p.i., there is comparable total numbers of IFNγ+ CD4 and CD8 T cells between infection routes, whereas both CD4+IFNγ+ and CD8+IFNγ+ cells are producing significantly higher amounts of IFNγ upon i.p. infection compared to p.o. (Figures 5F, G). This evidence concerns the gene CD4 and infection.