Characterization of the antibody response specific for the human endogenous retrovirus HTDV/HERV-K.
Differentiated human teratocarcinoma cell lines produce the human teratocarcinoma-derived virus (HTDV) particles encoded by the human endogenous retrovirus sequence HERV-K. We screened almost 2,000 human sera for antibodies against this endogenous human retrovirus, HTDV/HERV-K. Specificity of the immunofluorescence reactions using particle producing teratocarcinoma cells was confirmed by immunoelectron microscopy of ultrathin frozen sections. Immunoblot analyses using lysates of HTDV-producing cells revealed a 80-kDa HERV-K Gag precursor and a 90-kDa putative viral Env protein after incubation with positive sera. No processed Gag protein could be observed. Virus-specific bands were not detected in lysates of nonproducing cells. High antibody titers were found in about 60% of male patients with germ cell tumors. Antibody reactivity declined after tumor removal. In healthy blood donors, anti-HTDV reactivity was found only at low titers in a small percentage (3.9%) of individuals. A slightly elevated but statistically significant percentage of HTDV positivity was also observed for sera of pregnant women, whereas human immunodeficiency virus-positive individuals exhibited no peculiarity compared to normal blood donors. Our results provide evidence that HTDV particles are expressed in vivo and that the immune reaction against HTDV/HERV-K is specific for defined viral proteins.
Boller
K
K
Paul-Ehrlich-Institut, Langen, Germany. Boller@em.uni-frankfurt.de
Janssen
O
O
Schuldes
H
H
Tönjes
R R
RR
Kurth
R
R
D000914:Antibodies, Viral / Q000276:immunology*; D000956:Antigens, Viral / Q000276:immunology*; D003001:Cloning, Molecular; D005260:Female; D017988:Gammaretrovirus / Q000276:immunology*; D015683:Gene Products, gag / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D011247:Pregnancy; D018239:Seminoma / Q000276:immunology; D018243:Teratocarcinoma / Q000382:microbiology*
D000914:Antibodies, Viral; D000956:Antigens, Viral; D015683:Gene Products, gag