CAD and infection: This decrease in liver parasite load is more marked than that observed under similar experimental conditions following passive transfer of 10 mg of IgGs from CPS-immunized volunteers, which is equivalent to the typical IgG concentration in human plasma.33 Collectively, these data show that immunization with PbVac elicits the production of high titers of functional antibodies, mostly targeting the PfCS antigen, capable of preventing a subsequent infection by human-infective parasites.