Lymphocyte function tests
Cellular immunodeficiencies can be difficult to diagnose, and often are pursued when humoral Immunodeficiencies have been ruled out using the tests above. Some information can be collected from the peripheral blood T cell distribution and expression of cell surface markers using flow cytometry. However, normal values may not reflect cell dysfunction. Therefore, peripheral blood lymphocyte proliferation and cytokine production upon mitogenic stimulation in vitro can be useful. In addition, a delayed hypersensitivity reaction test can be performed using an intradermal phytolectin injection.
Immunological testing in horses:
- serum immunoglobulin concentrations (IgG, IgM, IgA);
- pre- and post-vaccination serum tetanus toxoid or pneumococcal antibody titers;
- peripheral blood lymphocyte phenotyping;
- peripheral blood lymphocyte proliferation;
- peripheral blood neutrophil function (oxidative burst activity).