Decrease in neutrophil migration induced by endotoxin and suppression of interleukin-1 production by macrophages in lactic dehydrogenase virus-infected mice

Implications of infectious agents on results of animal experiments

Report of the Working Group on Hygiene of the Gesellschaft für Versuchstierkunde–Society for Laboratory Animal Science (GV-SOLAS)

GV-SOLAS Working Group on Hygiene: Werner Nicklas (Chairman), Felix R. Homberger, Brunhilde Illgen-Wilcke, Karin Jacobi, Volker Kraft, Ivo Kunstyr, Michael Mähler, Herbert Meyer & Gabi Pohlmeyer-Esch

Natural pathogens of laboratory mice, rats, and rabbits and their effects on research

Laboratory mice, rats, and rabbits may harbor a variety of viral, bacterial, parasitic, and fungal agents. Frequently, these organisms cause no overt signs of disease. However, many of the natural pathogens of these laboratory animals may alter host physiology, rendering the host unsuitable for many experimental uses. While the number and prevalence of these pathogens have declined considerably, many still turn up in laboratory animals and represent unwanted variables in research. Investigators using mice, rats, and rabbits in biomedical experimentation should be aware of the profound effects that many of these agents can have on research.

Collagen-induced arthritis in mice: synergistic effect of E. coli lipopolysaccharide bypasses epitope specificity in the induction of arthritis with monoclonal antibodies to type II collagen

DBA/1 mice develop a chronic peripheral arthritis after immunization with type II collagen termed collagen-induced arthritis. We have localized the main arthritogenic determinants of CB11, a CNBr-generated arthritogenic fragment of chick type II collagen (CII), using 3 smaller peptide fragments of CB11 generated by endoproteinase LysC, LysC1 (CII 124-290), LysC2 (CII 291-374) and LysC3 (CII 375-402) and a panel of monoclonal antibodies (mAb) specific to CB11. MAb specific to the arthritogenic region of CB11 were also used to study the synergistic effect of E. coli lipopolysaccharide (LPS) on antibody-mediated arthritis in naive DBA/1 mice. LysC2 contained a minimum essential arthritogenic fragment of type II collagen: LysC2 induced arthritis by active immunization, also, a combination of four mAb specific to LysC2 passively transferred arthritis to naive mice. A single i.p. injection of LPS (50 micrograms/mouse) reduced the threshold values of the arthritogenic dose of mAb from 1 mg to 50 micrograms/clone per mouse, and decreased the number of mAb required for inducing arthritis from 4 to 2 clones. These observations suggest that LysC2, an 84 amino acid residue fragment, contains the main arthritogenic determinants within chick CB11. Importantly, LPS, a strong inducer of pro-inflammatory cytokines, negates the required multiple epitope specificity of autoantibodies in the passive transfer model and acts synergistically in the induction of arthritis by autoantibody.

Detection of the binding of IgG2a and IgG2b on the surface of macrophages from mice chronically infected with lactic dehydrogenase virus

This study showed that sera from mice chronically infected with lactic dehydrogenase virus (LDV) contained virus-antibody complexes (IC). IgG2a and IgG2b, but not IgG1, IgG3, IgM or IgA, were demonstrated on the surface of macrophages from chronically infected mice. These results suggest that IC in the circulation may bind to Fc receptors for IgG2a and IgG2b on the surface of macrophages and lead to the modulation of macrophage function seen in chronically LDV-infected mice.

Effect of prostaglandin E2 on plasma lactic dehydrogenase activity in (NZB x NZW)F1 mice with a chronic infection of lactic dehydrogenase virus

The effect of prostaglandin E2(PGE2) on blood LDH values was investigated in (NZB x NZW)F1 mice with or without an established infection with lactic dehydrogenase virus (LDV). Plasma LDH decreased in infected mice treated with PGE2, but increased in infected mice treated with indomethacin, an inhibitor of PGE2. However no significant effect on LDH occurred in uninfected mice treated with PGE2 or indomethacin. To investigate the mechanisms of decreased LDH activities resulting from treatment with PGE2, clearance tests were performed. Clearance of LDH-5, but not LDH-1, was faster in PGE2-treated mice than in non-treated mice, whether or not they were infected with LDV. The results suggest that enhanced clearance of LDH-5 in mice treated with PGE2 may account for the fall in plasma LDH in LDV-infected mice.

Macrophage function in the acute phase of lactic dehydrogenase virus-infection of mice: suppression of superoxide anion production in normal mouse peritoneal macrophages by interferon-alpha in vitro

The effect of interferon (IFN)-alpha on the release of superoxide anions (O2-) by normal mouse macrophages (PEM) was examined. Sera from LDV-infected mice at 1 day, but not at 7 days post-infection, suppressed the O2- release by PEM. When PEM were exposed in vitro for 24 h to IFN-alpha, their capacity to release O2- was significantly suppressed. Progressive suppression of O2- release with increasing IFN-alpha concentration was observed. These results suggest that IFN-alpha in the circulation may be one of several suppressive factors on macrophage function in the early phase of infection and IFN-alpha may play a modulatory role in inflammation and immunity.

Increased superoxide anion release by peritoneal macrophages in mice with a chronic infection of lactic dehydrogenase virus

The function of macrophages in mice chronically infected by lactic dehydrogenase virus (LDV) was studied. Superoxide anion (O2-) release was examined by using peritoneal macrophages. O2- release increased markedly from 3 weeks to 12 months, but not at 1 week post infection. O2- release was 1.2 to 1.5 times greater than in uninfected mice. Increased O2- release from macrophages in LDV-infected mice may explain, at least in part, suppressive effects on tumour growth seen in the chronic phase of infection.