Early postnatal development of the immune system in piglets: The redistribution of T lymphocyte subsets

In this study, we have characterised postnatal changes in T lymphocyte subsets, especially gamma delta T lymphocytes, in blood, spleen and lymph nodes. Detection was carried out using two-colour flow cytometry and three-colour immunohistochemistry. During ontogeny, there was a significant increase in the total percentage of gamma delta T cells in the spleen and blood. In the lymph nodes, there were no age-dependent changes in the total percentage of gamma delta T cells, but the percentage of the gamma delta TCR(+)CD8(+) subpopulation significantly increased. The tissue distribution of gamma delta TCR(+)CD8(+) and gamma delta TCR(+)CD8(-) cells in the lymph nodes is random and not collocated with a particular area of the organ. Furthermore, postnatal development was characterised by an increasing frequency of CD8(+)CD3(+)CD4(-)gamma delta TCR-, which was compensated by a decreasing proportion of CD4(+) lymphocytes. Double positive CD4(+)CD8(+) lymphocytes were rare during the first month of life and a significant age-dependent increase of these cells was found in all. the compartments monitored. (C) 2007 Elsevier Inc. All rights reserved.