Submitted to: Keystone Symposia
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 2010
Publication Date: October 27, 2010
Citation: Loving, C.L., Brockmeier, S.L., Vincent, A.L., Gauger, P.C., Kehrli, Jr., M.E. 2010. Influenza vaccination in the face of maternal antibody results in enhanced pneumonia following heterologous, homosubtypic influenza challenge [abstract]. Keystone Symposia, Immunological Mechanisms of Vaccination. Paper No. 243. Technical Abstract: Inactivated influenza vaccines do not provide cross-protection to diverse antigenic strains that could be circulating or suddenly arise in a population. It is desirable to vaccinate at a young age to provide maximum protection from influenza; however, maternally-derived factors (antibody or cells) can interfere with vaccine efficacy. In this study, sows were vaccinated with killed H3N2 influenza virus (kTx98) prior to pregnancy and again during gestation. Piglets were collected prior to suckling and half were cross-fostered (CF) to another vaccinated sow and half were returned to their respect dam for antibody transfer only vs antibody/cell transfer, respectively. Piglets were vaccinated at 2 and 4 weeks of age with the same vaccine (kTx98) and subsequently challenged with homologous virus (Tx98) or heterologous virus (Co99) at 8 weeks of age. Piglets vaccinated in the face of maternally-derived antibody (MDA), regardless of CF, displayed enhanced macroscopic lung lesions when challenged with homologous or heterologous virus, though lesions were worse following heterologous challenge. MDA alone (no piglet vaccination) did not provide protection as lung lesions were the same in non-vaccinated Tx98 challenged piglets as MDA non-vaccinated Tx98 challenged animals. Inactivated vaccine provided complete protection to homologous challenge when delivered to piglets without MDA interference. Vaccination in the face of MDA does inhibit an increase in HI titers to vaccine virus in vaccinated piglets, but does not alter development of total immunoglobulin levels to vaccine virus. IL-8 and IL-1beta cytokine levels and the percentage of CD4+ cell were significantly elevated in lungs of piglets challenged with heterologous virus when vaccinated in the face of MDA. Taken together, enhanced pneumonia following vaccination is dependent on the presence of MDA but not maternally-derived cells, and may be an important consideration in developing an efficacious vaccine regimen for influenza.