Biomaterial Database

Inhibition of human natural killer cell activity by Legionella pneumophila protease. 1989

C Rechnitzer, and M Diamant, and B K Pedersen

Department of Clinical Microbiology, Statens Seruminstitut, Copenhagen, Denmark.

The present study was undertaken to define the effect of Legionella pneumophila protease on natural killer (NK) cell function in vitro. Lysis of target cells by human NK cells was determined using a 51Cr-release assay. The protease inhibited the NK cell cytolytic activity in a concentration- and time-dependent manner. The inhibitory effect of the protease was not affected by alpha interferon or interleukin 2. Legionella pneumophila protease partly inhibited the binding of effector cells to target cells as studied in a single cell agarose assay of monocyte-depleted cell populations. This effect of the protease on the binding of NK cells to target cells could interfere with the previously described enhanced NK cell activity induced by Legionella pneumophila. We could demonstrate in vitro inhibition of NK cell activity by Legionella pneumophila protease at very low concentrations, suggesting a possible relevance of this mechanism in the pathogenesis of Legionnaires' disease.

UI	MeSH Term	Description	Entries
D007370	Interferon Type I	Interferon secreted by leukocytes, fibroblasts, or lymphoblasts in response to viruses or interferon inducers other than mitogens, antigens, or allo-antigens. They include alpha- and beta-interferons (INTERFERON-ALPHA and INTERFERON-BETA).	Interferons Type I,Type I Interferon,Type I Interferons,Interferon, Type I,Interferons, Type I
D007376	Interleukin-2	A soluble substance elaborated by antigen- or mitogen-stimulated T-LYMPHOCYTES which induces DNA synthesis in naive lymphocytes.	IL-2,Lymphocyte Mitogenic Factor,T-Cell Growth Factor,TCGF,IL2,Interleukin II,Interleukine 2,RU 49637,RU-49637,Ro-23-6019,Ro-236019,T-Cell Stimulating Factor,Thymocyte Stimulating Factor,Interleukin 2,Mitogenic Factor, Lymphocyte,RU49637,Ro 23 6019,Ro 236019,Ro236019,T Cell Growth Factor,T Cell Stimulating Factor
D007694	Killer Cells, Natural	Bone marrow-derived lymphocytes that possess cytotoxic properties, classically directed against transformed and virus-infected cells. Unlike T CELLS; and B CELLS; NK CELLS are not antigen specific. The cytotoxicity of natural killer cells is determined by the collective signaling of an array of inhibitory and stimulatory CELL SURFACE RECEPTORS. A subset of T-LYMPHOCYTES referred to as NATURAL KILLER T CELLS shares some of the properties of this cell type.	NK Cells,Natural Killer Cells,Cell, NK,Cell, Natural Killer,Cells, NK,Cells, Natural Killer,Killer Cell, Natural,NK Cell,Natural Killer Cell
D007875	Legionella	Gram-negative aerobic rods, isolated from surface water or thermally polluted lakes or streams. Member are pathogenic for man. Legionella pneumophila is the causative agent for LEGIONNAIRES' DISEASE.
D010447	Peptide Hydrolases	Hydrolases that specifically cleave the peptide bonds found in PROTEINS and PEPTIDES. Examples of sub-subclasses for this group include EXOPEPTIDASES and ENDOPEPTIDASES.	Peptidase,Peptidases,Peptide Hydrolase,Protease,Proteases,Proteinase,Proteinases,Proteolytic Enzyme,Proteolytic Enzymes,Esteroproteases,Enzyme, Proteolytic,Hydrolase, Peptide
D003602	Cytotoxicity, Immunologic	The phenomenon of target cell destruction by immunologically active effector cells. It may be brought about directly by sensitized T-lymphocytes or by lymphoid or myeloid "killer" cells, or it may be mediated by cytotoxic antibody, cytotoxic factor released by lymphoid cells, or complement.	Tumoricidal Activity, Immunologic,Immunologic Cytotoxicity,Immunologic Tumoricidal Activities,Immunologic Tumoricidal Activity,Tumoricidal Activities, Immunologic
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man