Development of apoptosis and changes in lymphocyte subsets in thymus, mesenteric lymph nodes and PEYER'S patches of mice orally inoculated with T-2 toxin

Development of apoptosis and changes in lymphocyte subsets were examined ma inly by flow cytometer in thymus, mesenteric lymph nodes and PEYER'S patche s of mice up to 24 hours after oral inoculation with T-2 toxin (10 mg/kg). T-2 toxin attacked PEYER'S patches first, then mesenteric lymph nodes, and finally thymus in relation to the course of enteric absorption of orally in oculated T-2 toxin. The degree of lymphocyte apoptosis was prominent in the thymus, moderate in the PEYER'S patches, and somewhat mild in the mesenter ic lymph nodes, suggesting the difference in lymphocyte population suscepti ble to T-2 toxin. As to the changes in lymphocyte subsets, CD4(+) CD8(+) T cells were most sensitive to T-2 toxin, and CD4(+) CD8(-) T cells were more severely depressed than CD4(-) CD8(+) T cells in the thymus. In the mesent eric lymph nodes, CD3(+) cells was more clearly affected than CD19(+) cells , and the numbers of CD4(+) and CD8(+) cells were similarly decreased. In t he PEYER'S patches, the numbers of CD3(+), CD19(+), CD4(+) and CD8(+) cells were unexceptionally decreased. In addition, among IgM(+), IgG(+) and IgA( +) B cells, the number of IA(+) B cells which are more important in the muc osal immunity was most severely affected.