Abstract
Immunohistochemistry (IHC) can be a valuable endpoint to evaluate lymphocyte subpopulations in tissues following exposure to presumptive immunosuppressive agents. IHC is more sensitive than conventional histology in detecting subtle differences in lymphocyte numbers and distribution in tissue. In combination with flow cytometric analysis of peripheral lymphocyte subpopulations, IHC can determine if alterations detected in the peripheral blood are a result of trafficking or reflective of changes in tissue distribution. These techniques can be used to evaluate adult animals as well as to evaluate the effects of immunosuppressive agents on fetal tissues in reproductive toxicology studies. While IHC can enhance the detection of subtle changes in lymphocyte subpopulations in tissue, the evaluation of additional end-points of immune function must be done to further assess the biological or clinical significance ofthese changes.
