title: Murine cytomegalovirus retinitis during retrovirus-induced immunodeficiency (MAIDS) in mice: interleukin-2 immunotherapy correlates with increased intraocular levels of perforin mRNA.
abstract: Mice with a retrovirus-induced immunosuppression (MAIDS) are susceptible to experimental murine cytomegalovirus (MCMV) retinitis, but can be rendered resistant to retinitis by systemic interleukin-2 (IL-2) immunotherapy. Experiments were performed to explore the mechanism by which IL-2 treatment during MAIDS might restore resistance to MCMV retinitis. Whereas 80% of untreated MAIDS mice were susceptible to MCMV retinitis, none (0%) of IL-2-treated MAIDS mice developed necrotizing retinitis. In comparison, 100% of both untreated and IL-2-treated perforin knockout mice (PKO mice) were susceptible to MCMV retinitis, and severity of retinitis and amounts of infectious intraocular MCMV in IL-2-treated PKO mice were equivalent to that in untreated PKO mice. A competitive quantitative RT-PCR assay was used to measure the levels of perforin mRNA within MCMV-infected eyes of immunologically normal mice, untreated MAIDS mice, and IL-2-treated MAIDS mice. Although the level of perforin mRNA within MCMV-infected eyes of untreated MAIDS mice susceptible to retinitis was significantly reduced when compared to the high level found within MCMV-infected eyes of normal mice resistant to retinitis, systemic treatment of MAIDS mice with IL-2 increased perforin mRNA within MCMV-infected eyes to levels found in normal mice. The ability of IL-2 treatment to increase intraocular levels of perforin mRNA diminished with the progression of MAIDS. Our findings support the hypothesis that systemic IL-2 immunotherapy during MAIDS provides protection against MCMV retinitis by upregulation of perforin-mediated cytotoxicity used by cytotoxic lymphocytes to kill virus-infected cells.
authors.affiliation: Harvery and Bernice Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA. dixrichardd@uams.edu
authors.forename: Richard D
authors.initials: RD
authors.lastname: Dix
authors.forename: Eckhard R
authors.initials: ER
authors.lastname: Podack
authors.forename: Scott W
authors.initials: SW
authors.lastname: Cousins
mesh_terms: D000818:Animals; D001483:Base Sequence; D017726:Cytomegalovirus Retinitis / Q000209:etiology / Q000276:immunology / Q000517:prevention & control*; D003602:Cytotoxicity, Immunologic; D005123:Eye / Q000276:immunology / Q000378:metabolism; D007167:Immunotherapy; D007376:Interleukin-2 / Q000627:therapeutic use*; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016183:Murine Acquired Immunodeficiency Syndrome / Q000150:complications* / Q000276:immunology / Q000628:therapy*; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000627:therapeutic use
chemical_list: D007376:Interleukin-2; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D054353:Perforin