Intravenous treatment with liposome-encapsulated dichloromethylene bisphosphonate (Cl2MBP) suppresses nitric oxide production and reduces genetic resistance to Marek's disease.

In this study the functional effectiveness of in vivo macrophage depletion using liposome-encapsulated dichloromethylene bisphosphonate (Cl(2)MBP) was examined in the chicken. The main target organs for systemic liposome-encapsulated Cl(2)MBP treatment are the spleen and the liver. Intravenous treatment with Cl(2)MBP of B(21)/B(21) chickens, genetically resistant to Marek's disease (MD), before challenge with the very virulent strain RB-1B, increased viral load in the blood and spleen after the first week and up to 6 weeks post-infection.

Antiviral and antitumoral effects of recombinant chicken myelomonocytic growth factor in virally induced lymphoma.

Chicken myelomonocytic growth factor (cMGF) is a 27-kDa glycoprotein that stimulates the growth and activation of cells from the monocyte/macrophage lineage. Recombinant cMGF was produced in a prokaryotic (Escherichia coli) expression system and purified via a C-terminal His-tag. Treatment of 2-week-old histocompatible B(13)/B(13) chickens highly susceptible to Marek's disease (MD) with rcMGF (two daily injections of 50 microg rcMGF per chicken) enhanced background and LPS-inducible systemic NO (NO3- + NO2-) responses 3 days later.

Resistance and susceptibility to Marek's disease: nitric oxide synthase/arginase activity balance.

The metabolic NO pathway, catalyzed by the enzyme NO synthase in macrophages, is a key defense element against viruses and tumors. However, arginase is an other enzyme able to metabolize the substrate L-arginine, and the two enzymes are alternatively regulated by Th1 and Th2 cytokines in murine macrophages. Marek's disease is characterized by strong immunosuppression and development of T-cell lymphomas in chickens.

Similar pattern of iNOS expression, NO production and cytokine response in genetic and vaccination-acquired resistance to Marek's disease.

NO is produced by macrophages through activation of the inducible enzyme NOS and its production is triggered as an antiviral and antitumoral immune mechanism. Replication of Marek's disease herpes virus (MDV) is inhibited by NO in vitro. MDV induces T-lymphomas in the chicken and a genetic resistance to tumor development has been linked to the B21 major histocompatibility complex.

Protective effect of avian myelomonocytic growth factor in infection with Marek's disease virus.

Marek's disease virus (MDV) is a herpesvirus that induces T lymphomas in chickens. The aim of this study was to assess the role of the macrophage activator chicken myelomonocytic growth factor (cMGF) in controlling MDV infection. B13/B13 chickens, which are highly susceptible to MD, were either treated with cMGF delivered via a live fowlpox virus (fp/cMGF) or treated with the parent vector (fp/M3) or were left as untreated controls.