The hamster as an experimental animal for the study of influenza. I. The role of antibody in protection.

Hamsters were used to examine the role of serum antibody in protection against influenza virus infection. Following intranasal instillation, influenza viruses replicated well in these animals, and high, reproducible amounts of virus could be subsequently recovered from nasal washings and lung suspensions. A specific serum antibody response to the infecting virus was also observed; but no local antibody production was detected. The passive transfer of serum antibody gave some measurable protection, against homologous influenza virus challenge, to recipient hamsters. However, evidence that protection can occur in the absence of detectable serum antibody in individual hamsters, is also presented.