EN
The study evaluated the status of pigs immunological systems during streptococci and mixed infections of the respiratory tract caused by S. suis, Mhp and PPRSV. T lymphocytes, including the proportions of Th and Tc subpopulations, as well as B lymphocytes were examined. Additionally, CD2+ and CD8+ co-expression with the receptor for IL-2 (CD25) was analyzed. Immunodetection was performed using pairs of monoclonal antibodies against CD2 and CD21, CD4 and CD8 as well as CD5 and CD8, with isotype specific polyclonal antibodies conjugated to fluorochromes. Infections caused by S. suis as well as mixed infections of the respiratory tract resulted in an increase in the total blood leukocyte count, noted in the peak of the disease as well as 4 weeks later. However different mechanisms of specific cellular defense were apparent during streptococci and poliethiological respiratory infections in the pigs. An increase in the percentage of Tc lymphocytes and double positive CD4+CD8+ cells without a decrease in the number of B lymphocytes was noted in animals infected with S. suis. An increase in the number of Th and Tc double positive lymphocytes as well as NK cells was observed during infections caused by S. suis, Mhp and PRRSV. Additionally, a significant decrease of CD2+ and CD8+ activated T cells co-expressed with CD25 was observed in this group of animals accompanied by an increase in the population of the above cells without the expression of IL-2R receptor.