Comparison of cytokine mRNA expression in peripheral CD4 + , CD8 + and γδ T cells between healthy H olstein and J apanese B lack calves

Japanese Black ( JB ) calves are more susceptible to infectious diseases compared to H olstein ( H ol) calves. To clarify the immunological differences between JB and H ol calves, expression of cytokine messenger RNA ( mRNA ) was examined using peripheral CD4 + , CD8 + and γδ T cells. Healthy calves, 24 from each species, were examined. Blood samples were obtained from calves at 1 week, 1 month and 3 months old, eight calves for each age of each species. Peripheral blood mononuclear cells were stimulated with phytohemagglutin ( PHA ), and T cell subsets were isolated by positive selection using magnetic cell sorting ( MACS ). Levels of interlekin ( IL )‐2, IL ‐4, IL ‐10 and interferon ( IFN )‐γ mRNA in three T cell subsets were analyzed. WC1‐N1 + γδ T cell percentages were significantly lower in JB calves at 1 week and 1 month of age compared to H ol calves. In addition JB calves had significantly lower IL ‐2, IL ‐10 and IFN ‐γ mRNA in WC1‐N1 + γδ T cells at 1 and 3 months of age, whereas there were no significant differences in cytokine mRNA of CD4 + and CD8 + cells between the two groups. Decreased cytokine mRNA and cell number of peripheral γδ T cells may affect negatively on the immune system of JB calves.