Longevity and the immune response.

The domino hypothesis of the onset of age associated immune insufficiency suggests that it is the consequence of a cascade of events beginning with involution of the thymus. Involution is associated with a reduced thymic output leading to fewer naïve T cells contributing to the peripheral T-cell pool. Homeostatic mechanisms, which maintain the number of T cells in the peripheral pool within precise limits, induce the proliferation and prolong the survival of resident T cells to fill the niches left vacant by the absent naïve T cells.

Evaluation of the cervical cytobrush sampling technique for the preparation of CD45+ mononuclear cells from the human cervix.

A cytobrush technique developed to prepare mononuclear cells from the intraepithelial layer of the endocervix has been evaluated. Specimens yielded approximately 4-6x10(6) cells, of which 10-15% were CD45+. Between 10% and 15% of these CD45+ cells were mononuclear leukocytes.