HUMORAL RESPONSE AND CHANGES IN IL-2 RECEPTOR'S EXPRESSION AFTER IMMUNISATION OF PIGLETS WITH MATERNAL ANTIBODIES AGAINST AUJESZKY'S DISEASE

The aim of the study was the evaluation Of immunological response of piglets born from SOWS immunised with ADV live vaccine and defining the optimal time for their active immunisation. Two weeks after the final vaccination, there were no differences in the level of serum gB antibodies among the sows and all the sows developed humoural immunity. Maternally derived antibodies (MDA) in the sera of all piglets were above the level considered to be positive until about I I weeks of their life, Following exposure to the live ADV, a greater number of lymphocytes (including CD2(+) and CD2(-) cells) from vaccinated animals expressed the IL-2 receptor (CD25), than those from unvaccinated ones. After virus stimulation, there were also higher expression of CD25 on CD8(+) T cells in all vaccinated animals, while in non-vaccinated pigs; a decrease in Such expression was evident. Based on the obtained results it might be stated that the piglet vaccination against AD at 10 and 14 weeks of life was considered to be optimal. In this age, the animals were still protected by passive immunity, but simultaneously were able to develop an active humoural response. It could be also concluded that the high level of MDA may successfully blocked the developmental of active immunity.