The hamster as an experimental animal for the study of influenza. II. The role of spleen cells in protection.

Hamsters previously infected by influenza viruses, have been shown to have a cell-mediated immune response, as measured by the macrophage migration inhibition test. The participation of spleen cells in the protection of recipients against homologous influenza virus infection was also demonstrated using adoptive transfer experiments. However, the protection achieved by spleen cell transfer was marginal and not observed in every animal. The time at which the spleen cells were transferred following infection, and their number, affected the outcome. Evidence suggesting that transferred spleen cells protected recipient hamsters through specific antibody is presented.