Identification of a vaccine candidate antigen, PfMAg-1, from Plasmodium falciparum with monoclonal antibody M26-32.
Monoclonal antibody M26-32 has been shown to strongly inhibit the growth of Plasmodium falciparum in vitro. To identify the target antigen of M26-32, a P. falciparum Dd2 asexual stage cDNA expression library was screened with this antibody, and a full open reading frame cDNA was obtained. This gene, named pfmag-1, encodes a polypeptide of 589 amino acids. The protein PfMAg-1 was characterized as a membrane-associated protein that expressed on the surface of merozoite during erythrocytic stage. Remarkably, at the C terminus of PfMAg-1, there are 14 copies of a deca-peptide sequence of QTDEIKND (H/N) I. This tandem repeat domain was identified to harbor the epitope of the protective M26-32 monoclonal antibody, and was also recognized by sera of patients infected with P. falciparum. Rabbit antibody elicited against this deca-peptide repeat domain effectively inhibited P. falciparum invasion in vitro. Our work suggests that PfMAg-1 is a promising malaria vaccine candidate.
Department of Etiology, Molecular Parasitology Laboratory, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, 100005, People's Republic of China.
Yu-Hui
YH
Gao
Hui-Liang
HL
Li
Yan
Y
Lu
Fang-Ming
FM
Gao
Ya-Hui
YH
Lin
Hong-Chang
HC
Zhou
Lian-Hui
LH
Zhang
Heng
H
Wang
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000913:Antibodies, Protozoan / Q000276:immunology*; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology*; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology; D006801:Humans; D017780:Malaria Vaccines / Q000235:genetics / Q000276:immunology*; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology*; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology*; D011817:Rabbits; D020449:Repetitive Sequences, Amino Acid; D017422:Sequence Analysis, DNA
D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D000939:Epitopes; D017780:Malaria Vaccines; D008565:Membrane Proteins; D015800:Protozoan Proteins