Aa. Chepurnov et al., Suppressive effect of Ebola virus on T cell proliferation in vitro is provided by a 125-kDa GP viral protein, IMMUNOL LET, 68(2-3), 1999, pp. 257-261
Ebola virus (EV), an extremely infectious pathogen, causes severe hemorrhag
ic fever in humans and nonhuman primates. The disease pattern includes dama
ge of parenchymal cells of vital organs in association with hemostatic and
immune disorders. Vaccination with the inactivated virions does not provide
an effective immune protection against the disease. The inadequate immune
response may be directly caused by the virus, and, hence, it may presumably
be crucial in the pathogenic process and prophylactic treatment of Ebola i
nfection. The suggested immunosuppressive properties of EV were examined in
this study. We have demonstrated that the whole heat-inactivated virions c
an dose-dependently suppress human lymphocyte mitogen-stimulated proliferat
ion in vitro. In further analyses, we identified the viral protein responsi
ble for the suppressive effect, and we showed that it was provided by a pro
tein corresponding to a 125-kDa envelope glycoprotein (GP-125). The protein
alone inhibited lymphocyte proliferation, whereas the other viral proteins
were without significant effect on blastogenesis. To determine the immunos
uppressive properties of different portions of GP-125, deletion mutants of
GP were designed based on predicted localisation of antigen sites. They wer
e expressed as recombinant proteins and studied in proliferation assays. We
identified a 40-amino acid sequence at the N-terminus of GP-125 that exert
ed a suppressive effect on blastogenesis. (C) 1999 Elsevier Science B.V. Al
l rights reserved.