Human phase I vaccine trials of 3 recombinant asexual stage malaria antigens with Montanide ISA720 adjuvant

Two phase I vaccine trials were conducted to test the immunogenicity and sa fety of a vaccine containing three recombinant malaria antigens from the as exual stage of Plasmodium falciparum. The three antigens are a fragment of MSPI (190LCS.T3); MSP2 and a portion of RESA and were formulated in Montani de ISA720 adjuvant, These trials investigated the dose response of each ant igen for eliciting both antibody and T-cell responses and the immunogenicit y of a mixture of the antigens compared with the antigens injected separate ly. All three antigens elicited both antibody and T-cell responses. Strong T-cell responses were observed with 190LCS,T3 and RESA with stimulation ind ices exceeding 100 for peripheral blood leucocytes in some individuals. The antibody responses were generally weak. The human antibody responses obser ved with MSP2 in Montanide ISA720 were nor significantly different from tho se obtained in an earlier trial which used MSP2 with alum as the adjuvant, No antigenic competition was observed: volunteers receiving a mixture of an tigens had similar responses to those receiving the three antigens at separ ate sites. Tenderness and pain at the injection site were common over the f irst few days following immunization. In some volunteers, especially those receiving the highest doses tested, there was a delayed reaction at the inj ection site with pain and swelling occurring approximately 10 days after in jection. (C) 1999 Elsevier Science Ltd. All rights reserved.