A novel 70-kDa Triton X-114-soluble antigen of Plasmodium falciparum that contains interspecies-conserved epitopes.
In order to identify novel conserved integral membrane and other membrane-associated proteins of Plasmodium falciparum, lambda gt11-P. falciparum DNA library phages were immunoscreened with convalescent-phase mouse sera and rabbit antiserum against Triton X-114-soluble proteins of P. falciparum. One recombinant phage clone, L857, reacted with both of the antibody probes. Insert DNA (857 bp long) in L857 was 69% dA+dT rich and hybridized to a fragment of 1800 bp from mung bean nuclease-digested P. falciparum genomic DNA. The cloned parasite DNA did not show notable sequence homology with any known protein gene. The L857-encoded polypeptide, p34 (M(r) 34 kDa) was expressed in bacteria, fused to glutathione S-transferase (GST). The fusion peptide, GST-p34 (M(r) 62 kDa), was recognized by immune serum against Triton X-114-soluble antigens of P. falciparum and was reactive with anti-P. falciparum, anti-Plasmodium yoelii, and anti-GST sera. Rabbit antiserum raised against the fusion peptide recognized a 70-kDa protein from lysates of P. falciparum cells and a putative homologous 100-kDa protein from lysates of P. yoelii. The rabbit serum anti-fusion peptide antibodies bound to acetone-fixed P. falciparum-infected erythrocytes and, in immunofluorescent antibody tests, produced a punctate pattern of fluorescence suggesting that the 70-kDa native protein is associated with an apical organelle of the parasite.
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Malaria Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India.
Ray
P
P
Dhanda
V
V
Das
P K
PK
Paliwal
S
S
Sahoo
N
N
Patra
K P
KP
Das
L K
LK
Singh
B
B
Kironde
F A
FA
D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D001482:Base Composition; D001483:Base Sequence; D003001:Cloning, Molecular / Q000379:methods; D016054:DNA, Protozoan / Q000235:genetics; D003902:Detergents; D000939:Epitopes / Q000032:analysis*; D004912:Erythrocytes / Q000469:parasitology; D006801:Humans; D007106:Immune Sera; D008565:Membrane Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017830:Octoxynol; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology*; D011092:Polyethylene Glycols; D015800:Protozoan Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D011817:Rabbits; D011993:Recombinant Fusion Proteins; D017422:Sequence Analysis, DNA; D012995:Solubility; D013045:Species Specificity
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D003902:Detergents; D000939:Epitopes; D007106:Immune Sera; D008565:Membrane Proteins; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D011092:Polyethylene Glycols; D017830:Octoxynol; C010615:Nonidet P-40