Immune response against the exp-1 protein of Plasmodium falciparum results in antibodies that cross-react with human T-cell lymphotropic virus type 1 proteins.
To examine the role of the Plasmodium falciparum Exp-1 blood-stage protein in producing antibodies that cross-react with human T-cell lymphotropic virus type I (HTLV-I) proteins, we studied sera from Indonesian volunteers who seroconverted to malaria after transmigrating to an area where malaria is hyperendemic. Samples from Philippine volunteers, that were used in a prior study that examined malaria antibodies that cross-react with HTLV-I proteins, were also used. Eighty-three percent of the Indonesian transmigrants developed antibodies against the malaria Exp-1 protein by 6 months postmigration. Of these malaria seroconverters, 27% developed false-positive HTLV-I enzyme immunoassay (EIA) immunoreactivity, as indicated by indeterminate HTLV-I Western blot banding patterns. Five of the six Philippine samples tested were HTLV-I EIA false positive and Western blot indeterminate. When a recombinant Exp-1 protein was used in blocking experiments, the HTLV-I Western blot immunoreactivity of sera from both groups was either completely eliminated or greatly reduced. No effect on the Western blot immunoreactivity of truly HTLV-I-positive sera was seen. To determine if immunization with the recombinant Exp-1 protein could elicit the production of HTLV-I antibodies, six mice were inoculated with the recombinant protein. Following administration of three 50-microgram doses of the protein, four of the six mice developed antibodies that cross-reacted with HTLV-I proteins on Western blot. These results indicate that the immune response against the malaria Exp-1 protein may result in HTLV-I-cross-reacting antibodies that can lead to false-positive EIA and indeterminant Western blotting results.
Porter
K R
KR
Viral and Rickettsial Diseases Program, Naval Medical Research Institute, Bethesda, Maryland, USA. porterkr@namru2.com
Aguiar
J
J
Richards
A
A
Sandjaya
B
B
Ignatias
H
H
Hadiputranto
H
H
Ridley
R G
RG
Takacs
B
B
Wignall
F S
FS
Hoffman
S L
SL
Hayes
C G
CG
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology*; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D000953:Antigens, Protozoan / Q000276:immunology*; D015153:Blotting, Western; D003429:Cross Reactions / Q000276:immunology*; D015481:HTLV-I Antibodies / Q000097:blood; D015486:HTLV-I Antigens / Q000276:immunology*; D006801:Humans; D007124:Immunoenzyme Techniques; D007214:Indonesia; D051379:Mice; D010963:Plasmodium falciparum / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D014764:Viral Proteins / Q000276:immunology*
D000913:Antibodies, Protozoan; D000914:Antibodies, Viral; D000953:Antigens, Protozoan; D015481:HTLV-I Antibodies; D015486:HTLV-I Antigens; D015800:Protozoan Proteins; C063362:QF116 antigen, Plasmodium falciparum; D011994:Recombinant Proteins; D014764:Viral Proteins