Human T-cell lymphotropic virus type 1 gag indeterminate western blot patterns in Central Africa: relationship to Plasmodium falciparum infection.
To gain insight on the significance of human T-cell lymphotropic virus type 1 (HTLV-1) indeterminate serological reactivities, we studied villagers of South Cameroon, focusing on a frequent and specific HTLV-1 Gag indeterminate profile (HGIP) pattern (gag p19, p26, p28, and p30 without p24 or Env gp21 and gp46). Among the 102 sera studied, 29 from all age groups had a stable HGIP pattern over a period of 4 years. There was no epidemiological evidence for sexual or vertical transmission of HGIP. Seventy-five percent of HGIP sera reacted positively on MT2 HTLV-1-infected cells by immunofluorescence assay. However, we could not isolate any HTLV-1 virus or detect the presence of p19 Gag protein in cultures of peripheral blood mononuclear cells obtained from individuals with strong HGIP reactivity. PCR experiments conducted with primers for HTLV-1 and HTLV-2 (HTLV-1/2 primers) encompassing different regions of the virus did not yield HTLV-1/2 proviral sequences from individuals with HGIP. Using 11 peptides corresponding to HTLV-1 or HTLV-2 immunodominant B epitopes in an enzyme-linked immunosorbent assay, one epitope corresponding to the Gag p19 carboxyl terminus was identified in 75% of HGIP sera, while it was recognized by only 41% of confirmed HTLV-1-positive sera. A positive correlation between HTLV-1 optical density values and titers of antibody to Plasmodium falciparum was also demonstrated. Finally, passage of sera through a P. falciparum-infected erythrocyte-coupled column was shown to specifically abrogate HGIP reactivity but not the HTLV-1 pattern, suggesting the existence of cross-reactivity between HTLV-1 Gag proteins and malaria-derived antigens. These data suggest that in Central Africa, this frequent and specific Western blot is not caused by HTLV-1 infection but could instead be associated with P. falciparum infection.
Mahieux
R
R
Unité d'Epidémiologie des Virus Oncogènes, CNRS URA 1960, Institut Pasteur, Paris, France. rmahieux@pasteur.fr
Horal
P
P
Mauclère
P
P
Mercereau-Puijalon
O
O
Guillotte
M
M
Meertens
L
L
Murphy
E
E
Gessain
A
A
D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D015153:Blotting, Western; D002163:Cameroon / Q000453:epidemiology; D002648:Child; D003429:Cross Reactions; D004279:DNA, Viral / Q000097:blood; D015480:Deltaretrovirus Antibodies / Q000097:blood*; D015485:Deltaretrovirus Antigens / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D015683:Gene Products, gag / Q000737:chemistry / Q000276:immunology*; D015490:HTLV-I Infections / Q000453:epidemiology / Q000276:immunology* / Q000821:virology; D015491:HTLV-II Infections / Q000276:immunology / Q000821:virology; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D015367:Human T-lymphotropic virus 2 / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D016778:Malaria, Falciparum / Q000276:immunology* / Q000469:parasitology; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D010963:Plasmodium falciparum / Q000276:immunology
D000913:Antibodies, Protozoan; D004279:DNA, Viral; D015480:Deltaretrovirus Antibodies; D015485:Deltaretrovirus Antigens; D000939:Epitopes; D015683:Gene Products, gag; D010455:Peptides