Influence of vaccination with A/PR 8/34 (HO-N1) influenza virus on the oncogenic activity of polyoma virus in newborn Wistar rats.

Vaccination with the A/PR 8/34 (HO N1) strain of influenza virus can decrease significantly the oncogenic activity of polyomavirus in newborn Wistar rats. This effect was regularly observed when animals were vaccinated with 24 hr after birth, whereas vaccinations performed on Days 3 and 10 failed to influence the oncogenic potential of polyoma virus. In 3 series of experiments, influenza virus vaccination resulted in sigificantly decreased tumor rates, and, in a 4th series, in reduced tumor growth only. Heat inactivation of influenza virus failed to abolish its influence on the oncogenicity of polyoma virus. In most of the experiments, the antibody response to influenza virus was enhanced by inoculation of animals with polyoma virus. In contrast, polyoma virus antibody titers were, in some experiments, decreased, and, in others, not influenced by vaccination with influenza virus.