title: Enhanced type 1 immunity after secondary viral challenge in mice primed as neonates.
abstract: The goal of infant immunization against viral infection is to develop protective long term memory responses. Priming neonatal mice with a low dose of Cas-Br-E murine leukemia virus (Cas) results in adult-like, type 1 protective responses. However, other studies suggest that Ag priming of neonates leads to an increase in type 2 secondary responses even when primary responses were type 1. We assessed whether type 1 CD8+ T cell-mediated responses developed in murine neonates are maintained after secondary challenge with Cas in adulthood. Despite the induction of significant anti-viral CD8+-mediated cytotoxic T lymphocyte and IFN-gamma responses, initial neonatal priming led to a lower frequency of virus-specific T cells compared with adult priming. Adult frequencies were reached in mice primed as neonates only after secondary challenge in adulthood. A nonspecific and transient CD4+-mediated IL-4 response was present in all groups after secondary challenge with Cas or medium, indicating that this rise in type 2 cytokine production was not unique to mice that had been primed as neonates. Rather, type 1 anti-viral memory CD8+ T cell responses developed in neonatal mice are stable, protective, and enhanced after secondary challenge.
authors.affiliation: Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Shaza A
authors.initials: SA
authors.lastname: Fadel
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Ozaki
authors.forename: Marcella
authors.initials: M
authors.lastname: Sarzotti
mesh_terms: D000375:Aging / Q000276:immunology; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D007117:Immunization, Secondary / Q000379:methods; D007156:Immunologic Memory; D007274:Injections, Intraperitoneal; D009052:Leukemia Virus, Murine / Q000276:immunology*; D051379:Mice; D012192:Retroviridae Infections / Q000276:immunology* / Q000517:prevention & control; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000821:virology; D018417:Th1 Cells / Q000276:immunology*; D014412:Tumor Virus Infections / Q000276:immunology* / Q000517:prevention & control; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D014765:Viral Vaccines