Assessment of adaptive immune responses of dairy cows with -induced mastitis.

, an emerging pathogen related to cystic fibrosis, is known to cause potentially fatal infections in humans and ruminants, especially in immunocompromised individuals. However, the immune responses in cows following its infection have not been fully elucidated. In this study, T- and B-lymphocytes-mediated immune responses were evaluated in 15 -induced mastitis cows and 15 healthy cows with multi-parameter flow cytometry. The results showed that infection with was associated with a significant decrease in the number and percentage of B lymphocytes but with a significant increase in the proportion of IgGCD27 B lymphocytes. This indicated that humoral immune response may not be adequate to fight intracellular infection, which could contribute to the persistent bacterial infection. In addition, infection induced significant increase of γδ T cells and double positive (DP) CD4CD8 T cells but not CD4 or CD8 (single positive) T cells in blood. Phenotypic analysis showed that the percentages of activated WC1 γδ T cells in peripheral blood were increased in the infected cows. Interestingly, intracellular cytokine staining showed that cattle naturally infected with exhibited multifunctional TNF-αIFN-γIL-2 -specific DP T cells. Our results, for the first time, revealed a potential role of IgGCD27 B cells, CD4CD8 T cells and WC1 γδ T cells in the defense of -induced mastitis in cows.