Human immune response to rabies nucleocapsid and glycoprotein antigens

Antibodies to two components of rabies virus, nucleocapsid (N) and glycoprotein (G), were compared in 11 rabies patients with those in nine recipients of Vero cell rabies vaccine. All rabies vaccinees had antibodies to N and G components by day 10 after the first vaccine injection. A similar but not identical response was observed in three out of 11 rabies patients. Serum antibodies appeared in rabies patients as early as 3 days after onset of the first symptoms of the disease. In these antibody-positive rabies patients, levels of both antibodies, but particularly of anti-N antibody, were lower than in the vaccinated group. Our results suggest that the process of immune recognition and of antibody development in human rabies is more likely to occur early in the pre-clinical phase, and that reactivity to N protein may be crucial for elicitation of neutralizing antibody.