Infectious Diseases of Mice and Rats (1991) / Chapter Skim
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9. Hemopoietic System
9. Hemopoietic System
Pages 198-221
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From page 198... ...
Both Haemobartonella muris and Eperythrozoon coccoides are blood parasites. The murine leukemia viruses (MuLVs)
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From page 199... ...
However, since 1960 three epidemics of LCMV infection involving at least 236 human cases have occurred in the United States, and all have been associated with Syrian hamsters, either as laboratory animals bearing transplantable tumors or as pets (Gregg, 1975~. Because of the unique host-parasite relationship of LCMN: infection in mice, experimental infections in mice have been used extensively as models for the investigation of such diverse phenomena as virus-specific immunological tolerance, virus-induced T-cell-mediated immunopathology, virus-induced immune complex disease, in vivo viral interference, and activation of natural killer cells (Lehmann-Grube et al., 1983~.
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From page 200... ...
Although hamsters infected with LCMV were found to be widely dispersed in the United States in recent years, those infections were traced to a single hamster breeder and a nearby laboratory supplying investigators with transplantable hamster tumors (Gregg, 1975~. One can only conclude that past health monitoring procedures for hamsters and transplantable hamster tumors have been inadequate and that the spread of LCMV infection can be extremely insidious.
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From page 201... ...
(1976) studied experimental LCMV infections in hamsters and reported that hamsters with persistent viremia developed progressive ~lomerulonephritis and had reduced litter sizes.
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From page 202... ...
There is generalized lymphoid hyperplasia and perivascular accumulation of lymphocytes and plasma cells in all visceral organs (Pollard and Sharon, 1969, 19731. Interferon is thought to have a central role in the development of immune complex disease (~^iviere et al., 1980; Ronco et al., 1980; Jacobson et al., 1981; Saron et al.- 1982; Woodrow et al., 19821.
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From page 203... ...
test can be used in testing transplantable tumors and other biologic materials for contamination with LCMV (Rowe et al., 1959a, 19621. Alternatively, virus isolations in tissue
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From page 204... ...
LCMV has been a frequent contaminant of biologic materials used in research, including the following: a. Transplantable tumors of mice (DeBuryn, 1949; Stewart and Haas, 1956; Haas, 1960; Molomut and Padnos, 1965; Molomut et al., 1965; Collins and Parker, 1972; Bhatt et al., 1986)
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From page 205... ...
LCMV infection in mice causes induction of natural killer cell activity early in the infection and proliferation of virus-specific cytotoxic T lymphocytes in chronic infection (Zinkernagel and Doherty, 1975, 1979; Welsh, 1978; Welsh and Doe, 1980; Pfau et al., 19823. LCMV infection causes severe depression of humoral and/or cellular immunity in mice (Mims and Wainwright, 1968; Lehmann-Grube et al., 1972; Bro-Jorgensen and Volkert, 1974; Bro-Jorgensen et al., 1975; Guttler et al., 1975; Thomsen et al., 1982; Wu-Hsieh et al., 19881.
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From page 206... ...
Limited studies with heterologous antibody produced in rats or rabbits suggest that there are at least two seroloaically distinct strains (Bailey et al., 1965b; Cafruny and Plagemann, 1982; Rowson and Mahy, 19851. LDV can be propagated in primary tissue cultures of mouse origin, including spleen, bone marrow, embryo fibroblast, and peritoneal exudate cells.
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From page 207... ...
LDV infection is not likely to be seen in breeding colonies of laboratory mice, but is very likely to occur in mice used in certain types of experiments if appropriate preventive measures are not followed. Transmission occurs most readily during experimental procedures such as mouse-to-mouse passage of contaminated tumors, cells, or serum, or use of the same needle to inoculate multiple mice.
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From page 208... ...
and increased tumor growth (Michaelides and Schlesinger, 1974~; these functions gradually return to normal after weeks or months. Antigenic challenge by T-cell-dependent antigens within 24 hours of LDV infection leads to enhanced humoral responses, while challenge three weeks or longer after infection leads to diminished responses (Mergenhagen et al., 1967; Riley et al., 1975; Isakov et al., 1982c)
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From page 209... ...
Diagnosis Diagnosis of LDV infection usually is based on the finding of increased levels of LDH activity in the plasma of mice. Screening of transplantable tumors, virus inocula, and other preparations for LDV contamination is done by injecting, an aliquot into LDV-free mice and performing the LDlI assay on plasma or serum 72-96 hours later (Notkins, 1965; Collins and Parker, 1972; Brinton, 19821.
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From page 210... ...
LDV infection can enhance or suppress growth of transplantable mouse tumors. In general, tumor growth is enhanced early after LDV infection (because of depressed cellular immunity)
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From page 211... ...
It has high si~nificance for studies involving rat-to-rat passage of materials (e.g., transplantable tumors or inocula for experimental blood parasite infections)
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From page 212... ...
. Transmission is readily accomplished by injecting, biologic materials (e.g., blood, transplantable tumors, tissue homogenate)
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From page 213... ...
Alternatively, rats known to be free of Haemobartonella muris and other pathogens can be splenectomized and then injected parenterally with transplantable tumor homogenates, pooled blood from groups of rats, or other test materials, followed by attempts to demonstrate parasitemia (Baker et al., 1971; Cassell et al., 1979~. Animals that are several months of age are more susceptible than young rats to severe disease following splenectomy.
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From page 214... ...
Eperythrozoon coccoides S· r ~gnzJ'cance Eperythro oon coccoides has little significance for most experimental uses of mice. This a=,ent is highly significant for studies involvin~ mouseto-mouse passage of materials such as transplantable tumors or inocula for experimental blood parasite infections.
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From page 215... ...
Inadvertent transmission in biologic materials (such as transplantabletumors, inocula for passage of experimental parasitic infections, blood plasma, and cell-free filtrates) rather than natural transmission poses the greatest threat in modern research (Baker et al., 1971; Lindsey et al., 1978b; Iralu and Ganong, 19831.
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From page 216... ...
These mice are then inoculated intraperitoneally or intravenously with test material that is to be monitored for the infection (e.g., pooled blood or spleen from mice of a colony suspected of having latent infection, transplantable tumors, antisera, cell lines)
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From page 217... ...
. Murine Leukemia Viruses S~ ret IgnlJIcance This large group of genetically related viruses, referred to collectively as the marine leukemia viruses (MuLYs)
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From page 218... ...
Related viruses infecting mammalian hosts include baboon type C oncovirus; bovine leukosis virus; feline sarcoma and leukemia viruses; gibbon ape leukemia virus; guinea pig type C oncovirus; porcine type C oncovirus; rat type C oncovirus; woolly monkey sarcoma virus; and more recently? the human T-cell lymphotropic virus (HTLV)
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From page 219... ...
Horizontal transmission is inefficient but can occur by transfer of virus in saliva, sputum, urine, feces, or milk or by intrauterine infection. The exogenous type C oncoviruses, of which the Friend, Moloney, and Rauscher strains are prototypes, are laboratory variants that have been derived from transplantable tumors and are known to become integrated only in the DNA of somatic cell lines (Lieber and Todaro, 1975; Lilly and Mayer, 1980~.
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From page 220... ...
Expression of the viral genomes in mice with a low incidence of leukemia, however, can be induced by chemical carcinogens, radiation, and other stimuli. The complex mechanisms by which endo~enous MuLVs induce leukemia, in mouse strains with either a low or high incidence of leukemia, appear to involve the expression and interaction of multiple MuLV genomes of both ecotropic and xenotropic viruses through such processes as recombination, DNA transfection, and transcomplementation (Furmanski and Rich, 1982; Morse and Hartley, 1982; Famulari, 1983; Risser et al., 1983; Goff, 19841.
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From page 221... ...
Interference with Research Although all mice have endogenous MuLVs, their presence probably has little significance for most research purposes in which mice are used. MuLV expression and the associated occurrence of neoplasms, however, can present competing endpoints in some studies, e.=,., studies of the aging processes in various organs.
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