title: Memory T-cell immune response in healthy young adults vaccinated with live attenuated influenza A (H5N2) vaccine.
abstract: Cellular immune responses of both CD4 and CD8 memory/effector T cells were evaluated in healthy young adults who received two doses of live attenuated influenza A (H5N2) vaccine. The vaccine was developed by reassortment of nonpathogenic avian A/Duck/Potsdam/1402-6/68 (H5N2) and cold-adapted A/Leningrad/134/17/57 (H2N2) viruses. T-cell responses were measured by standard methods of intracellular cytokine staining of gamma interferon (IFN-γ)-producing cells and a novel T-cell recognition of antigen-presenting cells by protein capture (TRAP) assay based on the trogocytosis phenomenon, namely, plasma membrane exchange between interacting immune cells. TRAP enables the detection of activated trogocytosis-positive T cells after virus stimulation. We showed that two doses of live attenuated influenza A (H5N2) vaccine promoted both CD4 and CD8 T-memory-cell responses in peripheral blood of healthy young subjects in the clinical study. Significant differences in geometric mean titers (GMTs) of influenza A (H5N2)-specific IFN-γ(+) cells were observed at day 42 following the second vaccination, while peak levels of trogocytosis(+) T cells were detected earlier, on the 21st day after the second vaccination. The inverse correlation of baseline levels compared to postvaccine fold changes in GMTs of influenza-specific CD4 and CD8 T cells demonstrated that baseline levels of these specific cells could be considered a predictive factor of vaccine immunogenicity.
authors.affiliation: Department of Virology, Institute of Experimental Medicine, Acad. Pavlov St. 12, Saint Petersburg 197376, Russia.
authors.forename: T V
authors.initials: TV
authors.lastname: Chirkova
authors.forename: A N
authors.initials: AN
authors.lastname: Naykhin
authors.forename: G D
authors.initials: GD
authors.lastname: Petukhova
authors.forename: D A
authors.initials: DA
authors.lastname: Korenkov
authors.forename: S A
authors.initials: SA
authors.lastname: Donina
authors.forename: A N
authors.initials: AN
authors.lastname: Mironov
authors.forename: L G
authors.initials: LG
authors.lastname: Rudenko
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016207:Cytokines / Q000096:biosynthesis; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods; D007156:Immunologic Memory; D053121:Influenza A Virus, H2N2 Subtype / Q000235:genetics / Q000276:immunology; D053125:Influenza A Virus, H5N2 Subtype / Q000235:genetics / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D016865:Reassortant Viruses / Q000276:immunology; D014611:Vaccination / Q000379:methods; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology; D055815:Young Adult
chemical_list: D016207:Cytokines; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated