title: Measurement of cell-mediated immunity with a Varicella-Zoster Virus-specific interferon-gamma ELISPOT assay: responses in an elderly population receiving a booster immunization.
abstract: An interferon-gamma ELISPOT assay has been developed for assessment of cellular immune responses to Varicella-Zoster Virus (VZV) in large, multi-center clinical vaccine trials. We show that the assay performed best when testing peripheral blood mononuclear cells (PBMCs) that had been isolated and then frozen on the same day as blood was drawn, and that freezing PBMCs from blood that was stored overnight before processing resulted in dramatically reduced responses. This assay was used to monitor cell-mediated immunity (CMI) in response to a booster immunization with an investigational live, attenuated VZV vaccine in an elderly population that had been vaccinated 8-10 years previously. The booster vaccine elicited a 1.6- to 1.7-fold rise in the VZV-specific cellular immune response as measured by the ELISPOT assay. The increase from pre to post booster vaccination response was more pronounced (approximately 2.2-fold rise) in a subset of subjects who had received two prior immunizations with a live, attenuated vaccine.
authors.affiliation: WP26B-1144, Department of Virus and Cell Biology, Merck and Co., Inc., PO Box 4, West Point, PA 19486, USA. jeffrey_smith2@merck.com
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Smith
authors.forename: Myron
authors.initials: M
authors.lastname: Levin
authors.forename: Rupert
authors.initials: R
authors.lastname: Vessey
authors.forename: Ivan S F
authors.initials: IS
authors.lastname: Chan
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Hayward
authors.forename: Xu
authors.initials: X
authors.lastname: Liu
authors.forename: Robin M
authors.initials: RM
authors.lastname: Kaufhold
authors.forename: James
authors.initials: J
authors.lastname: Clair
authors.forename: Ira
authors.initials: I
authors.lastname: Chalikonda
authors.forename: Christina
authors.initials: C
authors.lastname: Chan
authors.forename: Maryann
authors.initials: M
authors.lastname: Bernard
authors.forename: William W
authors.initials: WW
authors.lastname: Wang
authors.forename: Paul
authors.initials: P
authors.lastname: Keller
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Caulfield
mesh_terms: D000368:Aged; D019433:Chickenpox Vaccine / Q000008:administration & dosage*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D014645:Herpesvirus 3, Human / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D007117:Immunization, Secondary; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000032:analysis* / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D019433:Chickenpox Vaccine; D007371:Interferon-gamma