SELECTION OF AN ADJUVANT FOR VACCINATION WITH THE MALARIA ANTIGEN, MSA-2

Various formulations of the Plasmodium falciparum merozoite surface an tigen, MSA-2, were made and tested in animals in order to select one f or use in human vaccine trials. Recombinant constructs representing bo th major allelic forms of MSA-2 were formulated with a range of adjuva nts and used to immunize rabbits, mice and sheep. After immunization, antibody responses obtained with the most potent adjuvants were at lea st tenfold greater than responses obtained with the least potent adjuv ant Alhydrogel, which was used as the reference standard, although its lower potency indicated against its further use in clinical trials. B ased on broadly similar results obtained with the three animal species , several adjuvants, including the water-in-oil adjuvant Montanide ISA 720, the oil-in-water adjuvant SAF-1, and liposomes containing lipid A formulated with Alhydrogel were demonstrated to. be potent and poten tially suitable for the clinical evaluation of MSA-2 as a candidate ma laria vaccine antigen. Of these, ISA 720 was selected for further tria l. (C) 1997 Elsevier Science Ltd.