title: The limits of protection by "memory" T cells in Ig-/- mice persistently infected with a gamma-herpesvirus.
abstract: Can CD4(+) and CD8(+) "memory" T cells that are generated and maintained in the context of low-level virus persistence protect, in the absence of antibody, against a repeat challenge with the same pathogen? Although immune T cells exert effective, long-term control of a persistent gamma-herpesvirus (gammaHV68) in Ig(-/-) microMT mice, subsequent exposure to a high dose of the same virus leads to further low-level replication in the lung. This lytic phase in the respiratory tract is dealt with effectively by the recall of memory T cells induced by a gammaHV68 recombinant (M3LacZ) that does not express the viral M3 chemokine binding protein. At least for the CD8(+) response, greater numbers of memory T cells confer enhanced protection in the M3LacZ-immune mice. However, neither WT gammaHV68 nor the minimally persistent M3LacZ primes the T cell response to the extent that a WT gammaHV68 challenge fails to establish latency in the microMT mice. Memory CD4(+) and CD8(+) T cells thus act together to limit gammaHV68 infection but are unable to provide absolute protection against a high-dose, homologous challenge.
authors.affiliation: Department of Immunology, St. Jude Children's Research Hospital, 332 North Lauderdale, Memphis, TN 38105, USA.
authors.forename: Samita
authors.initials: S
authors.lastname: Andreansky
authors.forename: Haiyan
authors.initials: H
authors.lastname: Liu
authors.forename: Heiko
authors.initials: H
authors.lastname: Adler
authors.forename: Ulrich H
authors.initials: UH
authors.lastname: Koszinowski
authors.forename: Stacey
authors.initials: S
authors.lastname: Efstathiou
authors.forename: Peter C
authors.initials: PC
authors.lastname: Doherty
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology; D018142:Gammaherpesvirinae / Q000276:immunology*; D007117:Immunization, Secondary; D007136:Immunoglobulins / Q000172:deficiency* / Q000235:genetics; D007156:Immunologic Memory / Q000276:immunology*; D008168:Lung / Q000821:virology; D051379:Mice; D013154:Spleen / Q000276:immunology / Q000821:virology; D015163:Superinfection / Q000276:immunology* / Q000821:virology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000821:virology*; D017735:Virus Latency / Q000276:immunology
chemical_list: D007136:Immunoglobulins