CD4 and infection: Clearly, since IgG antibodies and memory B-cells are generated to a wide range of pre-erythrocytic antigens, including those with expression restricted primarily to these stages, such as circumsporozoite protein (CSP), liver-stage antigen 1 (LSA1), and sporozoite threonine–asparagine-rich protein (STARP) (12–14), CD4+ T-cells must be induced by these stages of the infection.