title: Immunity to experimental Salmonella typhimurium infections in rats. Transfer of immunity with primed CD4+CD25high and CD4+CD25low T lymphocytes.
abstract: The protective effect of primed CD4+ T lymphocytes against a lethal dose of 10(8) viable Salmonella typhimurium was studied in Lewis rats. Primed CD4+ T lymphocytes were obtained by inoculating Lewis rats with a non-lethal dose of 10(6) viable S. typhimurium. Four weeks after the infection, spleen CD4+ T lymphocytes were separated using magnetic microspheres coated with an antibody against the CD4 molecule (W3/25). Subsequent sorting into activated and non-activated subpopulations using the p55 alpha-chain of the interleukin-2 receptor (CD25) as an activation marker was performed by a fluorescence-activated cell sorter. Untreated Lewis rats were injected with 10(4) different primed CD4+ T-cell populations 24 h prior to the lethal dose of 10(8) viable S. typhimurium. Blood samples were drawn from the orbital plexus 1, 2, 3, and 4 weeks after the infection, and analysed for specific IgM and IgG antibodies. Cell sorting revealed that 2/3 of the primed CD4+ T lymphocytes expressed high levels of CD25. Cell transfer revealed that both CD25high and CD25low expression populations could induce immunity against a lethal dose of S. typhimurium, whilst antibody analysis revealed that antibody levels were not correlated with protection against S. typhimurium infections, although it showed that a higher and more persistent level of specific IgG antibodies was produced in animals receiving the CD4+CD25high fraction. It is concluded that 10(4) primed CD4+ T lymphocytes can induce immunity in animals challenged with a lethal dose of S. typhimurium and that antibodies do not seem to be correlated with the immunity induced. The CD4+CD25high fraction was, however, associated with a higher and more persistent level of specific IgG antibodies.
authors.affiliation: Department of Biological Sciences, Royal Danish School of Pharmacy, Copenhagen.
authors.forename: P
authors.initials: P
authors.lastname: Thygesen
authors.forename: L
authors.initials: L
authors.lastname: Brandt
authors.forename: T
authors.initials: T
authors.lastname: Jørgensen
authors.forename: H B
authors.initials: HB
authors.lastname: Christensen
authors.forename: H P
authors.initials: HP
authors.lastname: Hougen
authors.forename: E T
authors.initials: ET
authors.lastname: Jensen
authors.forename: J
authors.initials: J
authors.lastname: Rygaard
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000637:transplantation; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D016219:Immunotherapy, Adoptive; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D015375:Receptors, Interleukin-2 / Q000032:analysis / Q000276:immunology*; D012481:Salmonella Infections, Animal / Q000276:immunology*; D012486:Salmonella typhimurium / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000637:transplantation
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008070:Lipopolysaccharides; D015375:Receptors, Interleukin-2