Many papers isolate CD4+ T-cells from whole blood. I am wondering approximately what proportion of naive T-cells there will be from such a sample? Are these predominately naive T-cells or are there more memory and effector cells?
Stemcell Technologies has a really good wall poster for this. You can enumerate roughly 80,000 to 760,000 naive CD4+ T cells from peripheral blood per mL. This is 1-10% of leukocytes.
One of the things you need to remember about memory cells is that they do circulate, but it follows that among the circulating subsets of memory cells, they highly express markers for lymph node localization such as CCR7 and CD62L. Their presence in the blood at a given time is influenced by a number of factors including disease state.
Likewise, effector cells are programmed to localize within infected or distressed tissues through the actions of chemokines and chemokine receptors. The presence of effectors will depend on the same sort of factors, and as effector T cells, they are typically either made anergic and die by apoptosis or differentiated into memory cells.