Catfish reovirus See channel catfish reovirus

cationic detergent A surface-active agent having positively charged surface ions.

cattle plague virus Synonym for Rinderpest virus.

Catu virus (CATUV) A species in the genus Bunyavirus, antigenically related to the Guama serogroup. Originally isolated from a young man with a febrile illness in Para, Brazil; 10 further isolations have been reported. Also isolated from bats, mosquitoes, sentinel monkeys and mice in Brazil, Trinidad and French Guiana.

cauliflower disease of eels virus A virus (EV2) isolated from a European eel, Anguilla anguilla, with stomatopapillo-mas. Eels develop lesions with a cauliflower-like appearance, predominantly around the mouth and head and consisting of hyperplastic squamous cells. An icosahedral virus has been isolated from the blood of affected eels, but the relationship of this virus to EV2, and of both to the disease is not clear. EV2 virus is 90-140nm in diameter and pleomorphic, with surface projections 10nm long. Concentrated preparations agglutinate chick and sheep erythrocytes. Spontaneous elution occurs at room temperature. Replicates in FHM cells, optimally at 15°C, producing syncytia and irregular masses of rounded cells which eventually lyze. Infectivity is ether-sensitive and does not survive much over 3 weeks at 4°C. Replication inhibited by actinomycin D but not idox-uridine. See eel virus American. Synonym: EV2 virus.

Nagabayashi T and Wolf K (1979) J Virol 30, 358

caviid herpesvirus 1 (CavHV-1) An unas-signed member in the family Herpesviridae. A silent infection of guinea pigs; inclusion bodies can be found in cells of the salivary gland ducts. The infection can be passed experimentally by peripheral injection of salivary gland extract. Inoculation i.c. causes fatal meningitis. Intratracheal inoculation causes pneumonia. There is replication in primary guinea pig fibroblast culture with the appearance of small foci of enlarged cells in 10 days. Nuclear inclusions appear and on passage CPE may be seen in 1-2 days. The virus is cell-associated.

Synonyms: guinea pig herpesvirus 1; Hsiung-Kaplow herpesvirus.

Fong CKY et al (1979) J Gen Virol 42, 127 Smith MG (1959) Prog Med Virol 2, 171

caviid herpesvirus 2 (CavHV-2) An unas-signed member in the subfamily Betaherpesvirinae. Isolated from cultures of strain 2 guinea pig cells which developed focal areas of swollen rounded cells 9-13 days after preparation. No virus was obtained from homogenized guinea pig tissue extracts. Not reported to cause disease in guinea pigs or other animals. Replicates in rabbit kidney cell, mink lung cell and Vero cell cultures, but not in monkey, hamster, human or fowl CMA cells. Infective virus in rat cells does not kill them all and transformed cells appear which on injection grow into tumors and contain viral antigen. The virus is not neutralized by caviid herpesvirus 1 antiserum.

Synonyms: guinea pig herpesvirus; guinea pig cytomegalovirus; guinea pig salivary gland virus; guinea pig leukemia virus.

Rhim JS (1977) Virology 82, 100

caviid herpesvirus 3 (CavHV-3) An unas-signed virus in the family Herpesviridae. Originally isolated from the buffy coat of healthy guinea pigs and designated GPXV. Produced CPE in guinea pig embryo fibroblast cells. The viral DNA could be distinguished from other caviid herpesvirus DNAs by restriction enzyme analysis.

Synonym: guinea pig herpesvirus 3. Bia FJ et al (1980) J Virol 36, 245

CbaAr426 virus (CAV) A probable species in the genus Bunyavirus belonging to the Bunyamwera serogroup.

CCL Abbreviation for certified cell line, registered with the American Type Culture Collection (ATCC). See certified cell line.

CCR5 A chemokine receptor on cell surfaces which is used as a co-receptor (with CD4) for HIV, and binds cell signaling molecules called beta-chemokines (e.g. RANTES, MIP-1a and MIP-1ß). This interaction results in activation and movement of immune cells to sites of infection, leading to enhanced clearance of pathogens.

CD Cluster of differentiation. An internationally agreed system of naming differentiation antigens on cell surfaces. Several CD antigens act as relatively specific receptors for virus attachment, e.g. CD4 is a receptor for Human immunodeficiency virus; CD21 is a receptor for Epstein-Barr virus; CD46 is a receptor for Measles virus; and CD155 is a receptor for Poliovirus.

CD4 cells T lymphocytes which are effectors of the specific cellular immune response. Class II MHC restricted, the CD4 antigen is a receptor for binding HIV-1, and the onset of AIDS is associated with marked depletion of CD4 cells in the blood.

Dalgleish AG et al (1984) Nature 312, 776

CD8 cells T lymphocytes which are effectors of the specific cellular immune response. Class I MHC restricted.

cDNA Abbreviation for complementary DNA; formed by reverse transcription.

cDNA cloning Molecular cloning of a double-stranded DNA copy of an RNA molecule.

cDNA library A series of clones which represent all the mRNA sequences expressed in the cell from which they are derived. Only contains transcribed DNA sequences (exons), and no non-transcribed sequences (introns, spacer DNA). Obtained by synthesizing a cDNA copy of the mRNA population, converting this to double-stranded DNA, and integrating this DNA into the restriction site of a cloning vector. If an expression vector is used (e.g. lambda gt11), specific mRNAs may be identified using antibodies which react with particular expressed proteins.

cebine herpesvirus 1 (CbHV-1) An unas-signed species in the family Herpesviridae, isolated from a captive capuchin monkey, Cebus appella.

Synonyms: capuchin herpesvirus AL-5; owl monkey herpesvirus.

Lewis MA et al (1976) Infect Immun 14, 759

cebine herpesvirus 2 (CbHV-2) An unas-signed species in the family Herpesviridae, isolated from a captive capuchin monkey, Cebus appella.

Synonyms: capuchin herpesvirus AP-18; owl monkey herpesvirus.

cell-associated virus Virus particles which remain attached to or inside the host cell after replication. The amount of cell-associated compared to released virus varies considerably with the virus and/or the host cell involved. Cytomegaloviruses are a typical example of cell-associated virus.

cell counts The number of viable cells in a culture can be determined using a vital stain, which is excluded by living cell membranes and is incorporated only into dead cells. Trypan blue is the most commonly used vital stain for this procedure.

George VG et al (1996) In Virology Methods Manual, edited by BWJ Mahy and HO Kangro. London: Academic Press, p. 3

cell culture Growth of dispersed cells in vitro as single layers (monolayers) on a glass or plastic surface, or as suspensions, in liquid or soft gel medium. A culture derived from cells taken directly from the tissue of origin is called a 'primary culture'. The first subculture of a primary culture may give rise to a cell line. See tissue culture.

cell cycle Cytological study identifies only two phases in the cell growth cycle: (1) mitosis, during which the chromosomes become visible and undergo redistribu tion within the cell which then divides; and (2) interphase, which occupies the majority of the cell growth cycle. Biochemical analysis has resulted in the subdivision of interphase into three phases characterized by their metabolic activity, the most prominent of which is the period of DNA synthesis (S), usually lasting 6-8 h, which occurs in the middle of interphase. The gap between mitosis (M) and the S phase is known as G1, and the second, between S and M, is known as G2. Thus the cell cycle occurs as M-G1-S-G2-M-etc. Most viruses are able to multiply in cells independently of cell division or the stage in the cell cycle at which infection occurs. However, the Parvoviridae are an exception and require rapidly dividing cells for the establishment of infection.

cell death Programmed cell death is a physiological process that induces apoptosis, a form of cellular suicide. Apoptosis enables unwanted cells such as virus-infected cells to be eliminated, and rapid cell death reduces virus spread.

Quinlan MP (1999) In Encyclopedia of Virology. Second edition, edited by A Granoff and RG Webster. London: Academic Press, p. 68

cell-free translation An in vitro system for translating added viral or cellular mRNAs into proteins. The most commonly used systems are derived from wheat germ, rabbit reticulocytes or ascites tumor cells.

cell fusion Formation of multinucleate giant cells (syncytia) by fusion of cell membranes. Enveloped viruses have a membrane glycoprotein with fusion activity. Virus-induced fusion from outside the cell can be caused by exposure to high multiplicity of virus (e.g. Sendai virus), even when the virus nucleic acid has been inactivated. Such fusion can be mediated by the fusion protein alone, acting at the cell surface. Fusion within the cell occurs with several enveloped viruses such as influenza, Semliki Forest virus and Vesicular stomatitis virus, which are taken up into endosomal vesicles by receptor-mediated endocytosis. Fusion between the viral and endosomal membranes is triggered by a reduction in pH within the endosome.

centrophyten cell-fusing agent virus (CFAV) A tentative species in the genus Flavivirus isolated from Aedes aegypti cells that may be the present-day survivor of the primeval

Flavivirus.

cell line A population of cells arising from a primary cell culture at the time of the first subculture. They are of two types, euploid (e.g. diploid) or aneuploid (het-eroploid). Euploid cells, e.g. normal human fibroblasts, retain their normal karyotype throughout their culture lifespan, rarely give rise to continuous cell lines, and stop dividing after about 50 generations. Aneuploid cells, e.g. tumor-derived cells, may give rise to continuous cell lines that can be cultured indefinitely, but have an abnormal kary-otype. A cloned cell line is descended from a single cell clone. A diploid cell line is one where at least 75% of cells have the same karyotype as normal cells of the species from which the line was derived. A heteroploid cell line has less than 75% of cells which are of normal karyotype.

cell-mediated immunity Immunity mediated by cells of the T-lymphocyte lineage, distinguished from humoral immunity which results from secretion of immunoglobulins by B lymphocytes. T and B lymphocytes form an integrated system to generate a specific response to virus infection. The initial stages of induction of immunity involve uptake of antigen (virus or virus proteins) by dendritic cells, where proteolysis occurs and antigen-specific peptides fuse with MHC class II molecules and are presented in association with the MHC class II molecules on the cell surface. The complex so presented is recognized by the T-cell receptor and CD4 molecule on CD4T cells resulting in clonal expansion, and production of growth factors that induce proliferation and differentiation of both T and B lymphocytes. Cytotoxic CD8 T lymphocytes recognize a complex of MHC class I with a foreign peptide on the surface of infected cells and destroy them. B lymphocytes are stimulated to produce humoral antibodies to neutralize free virions, prevent spread of the infection and provide subsequent protection from reinfection.

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