M. hyopneumoniae -specific proliferation. M. hyopneumoniae specific proliferation by piglet blood mononuclear cells (BMC) was measured 7 days post vaccination (dpv) (panel A) and 14 dpv (panel B). Antigen-specific lymphoproliferation was determined by subtracting the percent unstimulated lymphoproliferation (media only) from the percent M. hyopneumoniae specific lymphoproliferation. Piglet treatment groups are as follows: Ns Np: nonvaccinated sow, nonvaccinated piglet; Ns Vp: nonvaccinated sow, vaccinated piglet; Vs Vp: vaccinated sow, vaccinated piglet; Vs Np: vaccinated sow, nonvaccinated piglet; n = 10/group. Error bars are SEM; different subscripts represent significance at p < 0.05.