Mechanism of depletion of T lymphocytes from the spleen of mice infected with Listeria monocytogenes.

Marked changes in the splenic lymphocyte populations during murine infection with Listeria monocytogenes were observed histologically and quantitated by the immunofluorescence of Thy-1+ immunoglobulin (Ig-) (T) and Ig+ (B) cells. Cells were depleted from the T-dependent areas of the spleen, and the number of T cells in suspensions prepared from spleens of mice 1 to 3 days after primary or secondary infection were less than 1/10 of normal. High numbers of alcohol-killed Listeria sp. did not cause any depletion. Depletion was not prevented by adrenalectomy. Although injected radiolabeled T cells distributed normally between spleen, liver, lymph node, and gut in infected mice, there appeared to be a barrier to their entry into depleted T-dependent areas of the spleen. Evidence for the destruction of T cells, but not of B cells, in the infected mouse spleen was obtained.