In 2002, the World Health Organization reported a worldwide malaria incidence of approximately 300 million clinical cases annually, with approximately 1 million deaths attributed to malaria alone or in combination with other diseases. The parasite Plasmodium falciparum is responsible for the majority of these infections and deaths. During P. falciparum infection, liver cells are invaded by the parasite and asexual multiplication occurs. The liver cells burst, and tens of thousands of infectious particles called merozoites are released. A multiprotein complex on the surface of a merozoite is necessary for the merozoite to infect a blood cell. MSP1 42-C1 is a malaria vaccine that mimics MSP1 42, a protein in the multiprotein complex. By introducing this decoy form of MSP1 42, infection of additional blood cells may be blocked. The adjuvant CPG 7909 is known to elicit cell-mediated immunity, the arm of the immune system that defends the body against intracellular pathogens such as P. falciparum. This study will evaluate the safety and immunogenicity of MSP1 42-C1/Alhydrogel at two different doses in healthy adults. The vaccine will be given either alone or with CPG 7909.~This study will last at least 34 weeks. Participants will be randomly assigned to one of four groups:~Group A participants will receive three injections of the lower dose of MSP1 42-C1/Alhydrogel.~Group B participants will receive three injections of the lower dose of MSP1 42-C1/Alhydrogel and CPG 7909.~Group C participants will receive three injections of the higher dose of MSP1 42-C1/Alhydrogel.~Group D participants will receive three injections of the higher dose of MSP1 42-C1/Alhydrogel and CPG 7909.~Enrollment into Groups C and D will begin only after safety review of all participants in Groups A and B. All participants will receive their assigned injections at study entry, Week 4, and Week 8, and will be asked to return to the clinic the day after each vaccination for clinical evaluation. Participants will be asked to keep a diary for 6 days after each vaccination, taking note of their body temperatures and any side effects they experience. There will be a total of 18 study visits over 34 weeks. A clinical evaluation will occur at each visit. Blood collection, vital signs measurement, and urine collection will occur at selected visits.
The purpose of this study is to determine the safety of and immune response to a preventive malaria vaccine, MSP1 42-C1/Alhydrogel, in healthy adults. This study will also compare responses to two different doses of the malaria vaccine given with or without the adjuvant CPG 7909.