title: Immunization of Aotus nancymai with recombinant C terminus of Plasmodium falciparum merozoite surface protein 1 in liposomes and alum adjuvant does not induce protection against a challenge infection.
abstract: Merozoite surface protein 1 (MSP-1) of Plasmodium falciparum is an antimalarial vaccine candidate. The highly conserved 19-kDa C-terminal processing fragment of MSP-1 (MSP-1(19)) is of particular interest since it contains epitopes recognized by monoclonal antibodies which inhibit the invasion of erythrocytes in vitro. The presence of naturally acquired anti-MSP-1(19) antibodies in individuals exposed to malaria has been correlated with reduced morbidity, and immunization with an equivalent recombinant P. yoelii antigen induces substantial protection against this parasite in mice. We have expressed P. falciparum MSP-1(19) in Escherichia coli as a correctly folded protein and immunized Aotus nancymai monkeys by using the protein incorporated into liposomes and adsorbed to alum. After vaccination, the sera from these animals contained anti-MSP-1(19) antibodies, some of which competed for binding to MSP-1(19) with monoclonal antibodies that inhibit parasite invasion of erythrocytes in vitro. However, after challenge with either a homologous or a heterologous strain of parasite, all animals became parasitemic and required treatment. The immunization did not induce protection in this animal model.
authors: Division of Parasitology, National Institute for Medical Research, London, United Kingdom.
authors: P A
authors: PA
authors: Burghaus
authors: B T
authors: BT
authors: Wellde
authors: T
authors: T
authors: Hall
authors: R L
authors: RL
authors: Richards
authors: A F
authors: AF
authors: Egan
authors: E M
authors: EM
authors: Riley
authors: W R
authors: WR
authors: Ballou
authors: A A
authors: AA
authors: Holder
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000534:Alum Compounds; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis; D000953:Antigens, Protozoan / Q000008:administration & dosage*; D001029:Aotus trivirgatus / Q000276:immunology*; D008081:Liposomes; D017780:Malaria Vaccines / Q000008:administration & dosage; D020066:Merozoite Surface Protein 1; D010963:Plasmodium falciparum / Q000276:immunology*; D011498:Protein Precursors / Q000008:administration & dosage* / Q000276:immunology; D015800:Protozoan Proteins / Q000008:administration & dosage* / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage
chemical_list: D000276:Adjuvants, Immunologic; D000534:Alum Compounds; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D008081:Liposomes; D017780:Malaria Vaccines; D020066:Merozoite Surface Protein 1; D011498:Protein Precursors; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; C041524:aluminum sulfate