The IgG subclass responses to influenza virus haemagglutinin in the mouse: effect of route of inoculation.

The influence of the route of infection, regime of inoculation and virus preparation on murine IgG subclass responses to the haemagglutinin of influenza A virus were examined. Virus preparations inoculated by the intraperitoneal, intravenous, intramuscular and intranasal routes were found to induce different IgG subclass profiles after a primary and secondary dose. IgG2a was found to be a major contributor to the responses elicited by all virus preparations irrespective of the route of inoculation. The magnitude of the response varied with the number of doses of virus and the route of inoculation; the intravenous and intramuscular routes produced the largest responses after two doses of virus. Evidence for the local production of antibody is presented and the influence of antigen presentation on the induction of different subclass is discussed.