Inducible nitric oxide synthase is expressed in joints of goats in the late stage of infection with caprine arthritis encephalitis virus

Isolation and characterization of mesenchymal progenitors derived from the bone marrow of goats native from northeastern Brazil

PURPOSE

To characterize bone marrow progenitors cells grown in vitro, using native goats from northeastern Brazil as animal model.

METHODS

Ten northeastern Brazil native goats of both genders were used from the Piauí Federal University Agricultural Science Center's (UFPI) - Goat Farming Sector. Bone marrow aspirates where taken from the tibial ridge and seeded on culture plates for isolation, expansion and Flow Cytometry (expression markers - Oct-3/4, PCNA, Ck-Pan, Vimentina, Nanog).

RESULTS

Progenitor cells showed colonies characterized by the presence of cell pellets with fibroblastoid morphology. Cell confluence was taken after 14 days culture and the non-adherent mononuclear cell progressive reduction. After the first passage, 94.36% cell viability was observed, starting from 4.6 x 106 cell/mL initially seeded. Cells that went through flow cytometry showed positive expression for Oct-3/4, PCNA, Ck-Pan, Vimentina, and Nanog.

CONCLUSIONS

Bone marrow progenitor isolated of native goats from northeastern Brazil showed expression markers also seen in embryonic stem cells (Oct-3/4, Nanog), markers of cell proliferation (PCNA) and markers for mesenchymal cells (Vimentina and Ck-pan), which associated to morphological and culture growth features, suggest the existence of a mesenchymal stem cell (MSC) population in the goat bone marrow stromal cells studied.

Expanding possibilities for intervention against small ruminant lentiviruses through genetic marker-assisted selective breeding

Small ruminant lentiviruses include members that infect sheep (ovine lentivirus [OvLV]; also known as ovine progressive pneumonia virus/maedi-visna virus) and goats (caprine arthritis encephalitis virus [CAEV]). Breed differences in seroprevalence and proviral concentration of OvLV had suggested a strong genetic component in susceptibility to infection by OvLV in sheep. A genetic marker test for susceptibility to OvLV has been developed recently based on the TMEM154 gene with validation data from over 2,800 sheep representing nine cohorts. While no single genotype has been shown to have complete resistance to OvLV, consistent association in thousands of sheep from multiple breeds and management conditions highlight a new strategy for intervention by selective breeding. This genetic marker-assisted selection (MAS) has the potential to be a useful addition to existing viral control measures. Further, the discovery of multiple additional genomic regions associated with susceptibility to or control of OvLV suggests that additional genetic marker tests may be developed to extend the reach of MAS in the future. This review will cover the strengths and limitations of existing data from host genetics as an intervention and outline additional questions for future genetic research in sheep, goats, small ruminant lentiviruses, and their host-pathogen interactions.

Lesion development and immunohistochemical changes in granulomas from cattle experimentally infected with Mycobacterium bovis

Mycobacterium bovis, the causative agent of bovine tuberculosis, persists within granulomas. Formation of granulomas involves a complex array of immune activation and cellular migration. To examine temporal changes in granuloma development, we inoculated 32 cattle with M. bovis of deer origin. Tissues from 4 calves each were examined at 15, 28, 42, 60, 90, 180, 270, and 370 days after inoculation. Granulomas in the medial retropharyngeal lymph node were staged (I-IV) on the basis of cellular composition and the presence or absence of necrosis and peripheral fibrosis. Immunohistochemistry for inducible nitric oxide synthase (iNOS), CD68, CD4, CD8, and gamma/delta T cells was performed. Fifteen days after inoculation only stage I granulomas were seen, while between 28 and 60 days, there was a steady progression through granuloma stages such that by day 60, granulomas of all 4 stages were seen. Acid-fast bacilli were present in moderate-to-large numbers in stage I granulomas 15-60 days after inoculation. Stage IV granulomas contained large numbers of acid-fast bacteria. Abundant iNOS immunoreactivity was associated with granulomas from day 15 through day 60 but was minimal from day 90 to the termination of the experiment. The relative number of CD4+ and CD68+ cells remained constant throughout the study. In contrast, at time points >60 days, numbers of CD8+ and gamma/delta T cells diminished. Tuberculous granulomas are dynamic lesions that follow an orderly progression through disease stages. Diminished expression of iNOS and reduced numbers of CD8+ and gamma/delta T cells late in the progression of tuberculous granulomas may represent a failure of the host response to control infection.

Inhibition of nitric oxide enhances ovine lentivirus replication in monocyte-derived macrophages

Ovine lentivirus (OvLV) also known as maedi-visna virus, infects and replicates primarily in macrophages. This investigation examined the role of nitric oxide in the replication of OvLV in cultured macrophages. Peripheral blood mononuclear cells were collected from OvLV-free sheep and cultured in Teflon coated flasks at a high concentration of lamb serum. The cells were subsequently infected with OvLV strain 85/34. OvLV replication was assessed under different experimental treatments by comparison of reverse transcriptase (RT) activity in culture supernatant. Cultures that were treated with exogenous nitric oxide via S-nitroso-acetylpenicillamine did not have altered levels of RT activity compared to cultures treated with the inactive control compound, acetylpenicillamine. However, blockage of nitric oxide production by treatment with aminoguanidine, a competitive inhibitor of inducible nitric oxide synthase (iNOS), led to a significant rise in RT activity. This rise in RT activity was partially reversed in aminoguanidine treated cultures by L-arginine, the normal substrate for iNOS. Finally, the number of viral antigen producing cells was also quantified after aminoguanidine treatment and found to be significantly higher than untreated cultures. Collectively, these results indicate that nitric oxide is a negative regulator of OvLV replication in macrophages.