Early death of Japanese encephalitis virus-infected mice administered a neutralizing cross-reactive monoclonal antibody against glycoprotein E.

UNLABELLED: In the present study, the effect of two haemagglutination-inhibition (HAI)-negative auto-reactive (NHA-1 and NHA-2) monoclonal antibodies (MAbs) against glycoprotein E (gpE) of Japanese encephalitis virus (JEV) administered 1 day before or 2 days after intracerebral (i.c.) inoculation of JEV was studied in mice. Of the two MAbs that cross-reacted with West Nile virus (WNV) and histones, the first one (NHA-1) neutralized JEV, while the second one was non-neutralizing. NHA-1 MAb given intraperitoneally (i.p.) 1 day before virus infection induced early death by about 2 days in comparison to controls, whereas mice administered HAI-positive anti-gpE JEV specific MAbs (Hs-1 or Hs-4) were invariably protected. In contrast, MAb NHA-2 failed to produce any effect in mice. Since the similar virus titers were recorded in the brains of experimental and control infected mice, the present results indicated a modification of the biological activity of JEV by the pre-existing MAb NHA-1 that might be leading to an early death of mice.

KEYWORDS: Japanese encephalitis virus; neutralizing cross-reactive monoclonal antibody.