Vaccine development against blood-stage antigens is aimed at inducing inhibitory antibodies towards the circulating merozoites, thus preventing them from infecting red blood cells. One such blood stage candidate is the 19 kDa C-terminus of merozoite surface protein-1 (MSP-1C). MSP-1C has been shown to induce both inhibitory as well as blocking antibodies, the latter blocking the protective effects of the former. Inhibitory antibodies will bind to MSP-1C and inhibit merozoite invasion of red blood cell but the binding of blocking antibodies can prevent binding of inhibitory antibodies thereby...