Influence of immunomodulation on the development of Listeria monocytogenes infection in aged guinea pigs.

We investigated the impact of immunomodulation on the development of listeriosis within an aged population of guinea pigs after an intragastric challenge with Listeria monocytogenes. Supplementation with vitamin E for 35 days significantly increased the level of cytotoxic T cells (CD8(+)), while treatment with cyclosporin A resulted in a 25% decrease of CD8(+) T cells. In the animals receiving the low dose (10(2) CFU) of L.