title: CD4+ and CD8+ cells in cryopreserved human PBMC maintain full functionality in cytokine ELISPOT assays.
abstract: The frequency and the cytokine signature of antigen-specific T cells in the blood reflect the magnitude and the quality of T cell immunity in vivo. Recently, cytokine enzyme-linked immunospot (ELISPOT) assays performed on freshly isolated peripheral blood mononuclear cells (PBMC) emerged as a promising tool for monitoring these key parameters, providing direct feedback information on the efficacy of vaccinations and immune therapies. However, performing ELISPOT assays with freshly isolated cells is not readily feasible in the context of clinical trials. The ability to obtain valid ELISPOT data on cryopreserved samples would greatly enhance ex vivo immune monitoring capabilities. We have therefore systematically studied antigen-specific T cell responses in freshly isolated PBMC and after cryopreservation. Four healthy donors were selected that displayed T cell responses to six recall antigens. The antigen reactive T cells were defined as CD4 or CD8 cells, and their cytokine effector class was established measuring interferon (IFN)-gamma, interleukin (IL)-2, IL-4 and IL-5. The donors were bled at three different time points, and their PBMC were tested fresh and after freeze-thawing. The results showed that the frequencies and type 1/type 2 cytokine signatures of recall antigen-specific CD4 and CD8 cells are unaffected after cryopreservation. In contrast to these data obtained on human PBMC, cryopreservation of murine spleen cells causes a decrease in cytokine secretion.
authors.affiliation: Department of Pathology, School of Medicine, Case Western Reserve University, BRB 928, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
authors.forename: Christian R
authors.initials: CR
authors.lastname: Kreher
authors.forename: Markus T
authors.initials: MT
authors.lastname: Dittrich
authors.forename: Robert
authors.initials: R
authors.lastname: Guerkov
authors.forename: Bernhard O
authors.initials: BO
authors.lastname: Boehm
authors.forename: Magdalena
authors.initials: M
authors.lastname: Tary-Lehmann
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D015925:Cryopreservation; D016207:Cytokines / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D010641:Phenotype; D016176:T-Lymphocyte Subsets / Q000276:immunology*
chemical_list: D000956:Antigens, Viral; D016207:Cytokines