title: The antiviral CD8+ T cell response is differentially dependent on CD4+ T cell help over the course of persistent infection.
abstract: Although many studies have investigated the requirement for CD4(+) T cell help for CD8(+) T cell responses to acute viral infections that are fully resolved, less is known about the role of CD4(+) T cells in maintaining ongoing CD8(+) T cell responses to persistently infecting viruses. Using mouse polyoma virus (PyV), we asked whether CD4(+) T cell help is required to maintain antiviral CD8(+) T cell and humoral responses during acute and persistent phases of infection. Though fully intact during acute infection, the PyV-specific CD8(+) T cell response declined numerically during persistent infection in MHC class II-deficient mice, leaving a small antiviral CD8(+) T cell population that was maintained long term. These unhelped PyV-specific CD8(+) T cells were functionally unimpaired; they retained the potential for robust expansion and cytokine production in response to Ag rechallenge. In addition, although a strong antiviral IgG response was initially elicited by MHC class II-deficient mice, these Ab titers fell, and long-lived PyV-specific Ab-secreting cells were not detected in the bone marrow. Finally, using a minimally myeloablative mixed bone marrow chimerism approach, we demonstrate that recruitment and/or maintenance of new virus-specific CD8(+) T cells during persistent infection is impaired in the absence of MHC class II-restricted T cells. In summary, these studies show that CD4(+) T cells differentially affect CD8(+) T cell responses over the course of a persistent virus infection.
authors.affiliation: Department of Pathology, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Kemball
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Pack
authors.forename: Heath M
authors.initials: HM
authors.lastname: Guay
authors.forename: Zhu-Nan
authors.initials: ZN
authors.lastname: Li
authors.forename: David A
authors.initials: DA
authors.lastname: Steinhauer
authors.forename: Eva
authors.initials: E
authors.lastname: Szomolanyi-Tsuda
authors.forename: Aron E
authors.initials: AE
authors.lastname: Lukacher
mesh_terms: D000818:Animals; D000917:Antibody Formation; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D002908:Chronic Disease; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D007156:Immunologic Memory; D051379:Mice; D008810:Mice, Inbred C57BL; D011120:Polyomavirus / Q000276:immunology; D027601:Polyomavirus Infections / Q000276:immunology*
chemical_list: D000949:Histocompatibility Antigens Class II