Abstract: We utilized the silkworm (Bombyx mori)/baculovirus system to produce recombinant Major Merozoite Surface Protein 1 (MSP142) because of the low cost and potential high yield of this expression system. The MSP142 (3D7 sequence) was cloned into the baculovirus, BmNPV with the melittin signal sequence. The recombinant virus, BmNPV-Sp42 was used to infect silkworms for the expression of MSP142 (Sp42). One recombinant clone expressed high level of Sp42 with an estimated 0.5 mg of antigen produced within a single worm. The Sp42 was recognized by monoclonal and polyclonal antibodies specific for parasite MSP1 in direct binding and competitive binding ELISAs, suggesting that Sp42 possesses antigenic determinants similar to parasite MSP142. Immunogenicity studies were performed in rabbits. Sp42 induced high titers of antibodies crossreactive with MSP1. Specificity analyses showed that anti-Sp42 antibodies reacted primarily against conserved determinants on MSP1-19.