Expression of CD4, CD8, and CD25 surface markers on T lymphocytes and levels of IFNγ, IL-10, and TNF-α in colostrum and milk were determined in sows vaccinated against Trueperella pyogenes in the final stage of pregnancy. The autovaccine, prepared from Trueperella pyogenes, administered twice to pregnant sows six and three weeks before the anticipated delivery significantly increased the percentages of TCD4+, TCD8+, and TCD25+ as well as levels of IFNγ, TNF-α, and IL-10 in colostrum and milk. The enhanced immune potential of colostrum effectively protected the piglets against T. pyogenes infections during weaning and thus reduced the economic losses on the particular farm concerned, where T. pyogenes infections occur endemically. Knowledge of the profile of cellular and humoral immune response in colostrum and milk of vaccinated sows will enable the design of a T. pyogenes infection prophylactic programme for suckling pigs and weaners, which are most susceptible to infections.