Effect of age and maternally-derived antibody status on humoral and cellular immune responses to vaccination of pigs against Erysipelothrix rhusiopathiae.

The effects of age and maternally-derived antibodies (MDA) on the immune response to Erysipelothrix rhusiopathiae were investigated in piglets orally vaccinated with a live E. rhusiopathiae vaccine at 6, 8 or 10 weeks of age. Seroconversion, determined by ELISA, was evident in MDA positive piglets vaccinated at 8 or 10 weeks of age and in all MDA negative vaccinates. Two weeks after vaccination in the presence of MDA, a T cell response, measured by a lymphocyte proliferation assay, was observed in 25% of piglets vaccinated at 6 weeks of age and in 100% of piglets vaccinated at 8 or 10 weeks of age. The post-vaccinal response to E. rhusiopathiae was more strongly influenced by the maternal antibody status of the piglet at the time of vaccination than the age of the piglet.