Problem Somatic cloning technology is beneficial for genetically producing excellent animals. However, many developmental problems of somatically cloned animals have been described. Some of them may cause disorders of the immune system, resulting in the fluctuation of the proportion of white blood cells (WBC), different from that of normal animals in peripheral blood.
Method of study In Holstein- cloned and normal cows, the fluctuation of granulocytes, monocytes, B cells and T cells, and further T cell subsets (CD4+, CD8+, γδ, CD8+γδ and WC1+γδ T cell) in peripheral blood were analyzed in early lactation stage (ELS) and mid to late lactation stage (MLS) by flow cytometry using specific monoclonal antibodies for cell surface markers.
Results In both ELS and MLS, there were no significant differences in the proportions of granulocytes, monocytes, B cells and T cells between cloned and normal cows. In T cell subsets, γδ and WC1+γδ T cells in cloned cows were significantly less frequent than in normal cows in ELS. The decreased proportions of γδ and WC1+γδ T cells recovered to the level of normal cows in MLS.
Conclusions The population of granulocytes, monocytes, B cells and T cells, and T cell subsets except for γδ and WC1+γδ T cells in cloned cows fluctuated in a manner similar to those of normal cows during lactation. In ELS, the proportions of γδ and WC1+γδ T cells temporarily declined in cloned cows, suggesting that cloned cows may fall into an immunosuppressive state in ELS.