title: Mechanism of killing by virus-induced cytotoxic T lymphocytes elicited in vivo.
abstract: The mechanism of lysis by in vivo-induced cytotoxic T lymphocytes (CTL) was examined with virus-specific CTL from mice infected with lymphocytic choriomeningitis virus (LCMV). LCMV-induced T cells were shown to have greater than 10 times the serine esterase activity of T cells from normal mice, and high levels of serine esterase were located in the LCMV-induced CD8+ cell population. Serine esterase was also induced in purified T-cell preparations isolated from mice infected with other viruses (mouse hepatitis, Pichinde, and vaccinia). In contrast, the interferon inducer poly(I.C) only marginally enhanced serine esterase in T cells. Serine esterase activity was released from the LCMV-induced T cells upon incubation with syngeneic but not allogeneic LCMV-infected target cells. Both cytotoxicity and the release of serine esterase were calcium dependent. Serine esterase released from disrupted LCMV-induced T cells was in the form of the fast-sedimenting particles, suggesting its inclusion in granules. Competitive substrates for serine esterase blocked killing by LCMV-specific CTL, but serine esterase-containing granules isolated from LCMV-induced CTL, in contrast to granules isolated from a rat natural killer cell tumor line, did not display detectable hemolytic activity. Fragmentation of target cell DNA was observed during the lytic process mediated by LCMV-specific CTL, and the release of the DNA label [125I]iododeoxyuridine from target cells and the accompanying fragmentation of DNA also were calcium dependent. These data support the hypothesis that the mechanism of killing by in vivo-induced T cells involves a calcium-dependent secretion of serine esterase-containing granules and a target cell death by a process involving nuclear degradation and DNA fragmentation.
authors.affiliation: Department of Pathology, University of Massachusetts Medical Center, Worcester, 01655.
authors.forename: R M
authors.initials: RM
authors.lastname: Welsh
authors.forename: W K
authors.initials: WK
authors.lastname: Nishioka
authors.forename: R
authors.initials: R
authors.lastname: Antia
authors.forename: P L
authors.initials: PL
authors.lastname: Dundon
mesh_terms: D000818:Animals; D002122:Calcium Chloride / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000201:enzymology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004247:DNA / Q000187:drug effects / Q000302:isolation & purification; D004533:Egtazic Acid / Q000494:pharmacology; D004950:Esterases / Q000032:analysis; D006461:Hemolysis; D007962:Leukocytes / Q000201:enzymology; D008216:Lymphocytic Choriomeningitis / Q000276:immunology*; D008217:Lymphocytic choriomeningitis virus / Q000276:immunology; D015636:Magnesium Chloride / Q000494:pharmacology; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000201:enzymology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D015636:Magnesium Chloride; D004533:Egtazic Acid; D004247:DNA; D004950:Esterases; C022635:serine esterase; D002122:Calcium Chloride