Enterovirus E infects bovine peripheral blood mononuclear cells. Implications for pathogenesis?

Introduction: Enterovirus E (EV-E) is a common viral pathogen endemic in cattle worldwide. Little is known, however, about its potential interactions with bovine immune cells. Material and Methods: The EV-E-permissiveness of bovine peripheral blood mononuclear cells (PBMCs) was evaluated. The infectious titres of extracellular virus were measured and the intracellular viral RNA levels were determined by reverse transcription quantitative PCR after cell inoculation. The effects of EV-E on cell viability and proliferative response were investigated with a methyl thiazolyl tetrazolium bromide reduction assay, the percentages of main lymphocyte subsets and oxidative burst activity of blood phagocytes were determined with flow cytometry, and pro-inflammatory cytokine secretion was measured with an ELISA. Results: Enterovirus E productively infected bovine PBMCs. The highest infectious dose of EV-E decreased cell viability and T-cell proliferation. All of the tested doses of virus inhibited the proliferation of high responding to lipopolysaccharide B cells and stimulated the secretion of interleukin 1ß, interleukin 6 and tumour necrosis factor α pro-inflammatory cytokines. Conclusion: Interactions of EV-E with bovine immune cells may indicate potential evasion mechanisms of the virus. There is also a risk that an infection with this virus can predispose the organism to secondary infections, especially bacterial ones.

In vitro immunomodulatory effect of nisin on porcine leucocytes.

Nisin, a lantibiotic bacteriocin, has been used for years as a natural food preservative. In addition to its antimicrobial activity, nisin also shows immunomodulatory properties, and the nisin-producing Lactococcus lactis strain has been successfully tested as a probiotic in weaned piglets. However, the impact of nisin on porcine immune cells has not yet been explored. The objective of the present study was to examine the in vitro immunomodulatory effect of nisin on porcine peripheral blood leucocytes. The whole heparinized blood samples or freshly isolated peripheral blood mononuclear cells (PBMCs) were incubated with different nisin concentrations (0, 1.56, 3.125, 6.25, 12.5, 25 or 50 µg/ml) for 1, 24, 48 or 72 hr. Escherichia coli bacteria were used to stimulate blood phagocytes, while concanavalin A and lipopolysaccharide from E. coli were used as mitogens. Control cells remained unstimulated. MTT colorimetric assay was used to evaluate PBMCs viability and mitogenic response. Phagocyte activity and T-cell proliferation were measured by flow cytometry. Flow cytometer was also used for immunophenotyping of T cells. Cytokine levels in the culture media were determined using commercial immunoassay (ELISA) kits. The highest concentration of nisin exhibited proliferative activity (p Ë‚ 0.05), stimulated interleukin-1 beta (IL-1ß) and interleukin-6 (IL-6) production (both at p Ë‚ 0.001), and increased the percentage of CD4+ CD8+ T cells (p Ë‚ 0.001) among unstimulated leucocytes. After cell stimulation, however, the highest nisin concentration showed antiproliferative activity (p Ë‚ 0.05), decreased phagocytic functions (p Ë‚ 0.05) and inhibited the synthesis of IL-6 (time- and concentration-dependent effect). As a typical bacterial product, nisin had a stronger impact on innate immune cells, and its effect on T cells was likely a consequence of the modulation of the activity of antigen-presenting cells. Nisin may be a good candidate as an immunomodulator in pig breeding.

Early Cytokine Response After Vaccination with Coxiella Burnetii Phase I in an Infected Herd of Dairy Cattle.

INTRODUCTION: Coxiella (C.) burnetii, the aetiological agent of Q fever, is able to modulate the macrophage/T-lymphocyte axis in an infected organism and impair synthesis of monokines and lymphokines. MATERIAL AND METHODS: The purpose of this research was to determine the levels of the cytokines that play a key role in the response to C. burnetii antigens (IL-1ß, IL-2, IL-6, IL-10, IFN-γ and TNF-α) in the serum of animals originating from an infected herd prior to vaccination (day 0) and at 1, 7, and 21 days afterwards. RESULTS: The vaccination of animals did not affect the production of IL-6, IL-1ß, or IL-2. The serum levels of these cytokines were too low to measure in most of the samples. The initial levels of TNFα, IFNγ, and IL-10 were higher in seropositive than in seronegative animals, although significant differences between seropositive shedders and seropositive nonshedders appeared only in the levels of IFNγ and IL-10. Additionally, the course of the post-vaccination response concerning these two cytokines was different among seronegative nonshedders, seropositive nonshedders, and seropositive shedders. CONCLUSION: It seems that analysis of the IFNγ and IL-10 concentrations in animal blood serum may have some practical value in an assessment of the health status of seropositive animals and post-vaccination response.

Commercial gold nanocolloid inhibits synthesis of IL-2 and proliferation of porcine T lymphocytes.

Recent intensive development of nanotechnology has broadened the use of noble metal nanocolloids in alternative medicine. Meanwhile, silver and copper nanoparticles are tested as potential feed additives in pig farming. Experiments on rodents prove that metal nanocolloids easily interact with macrophages and lymphocytes, although the specific nature of pigs' immune system means that rodent tests may not reflect fully the responsiveness of porcine T cells. Our purpose was to demonstrate the effect of a commercial gold nanocolloid on percentages and proliferation of T lymphocyte subpopulations and on IL-2 and IL-10 synthesis in porcine peripheral blood mononuclear cells tested in vitro. The nanocolloid was not cytotoxic to porcine leukocytes, nor did it affect resting T cells. However, high nanogold concentrations inhibited proliferation of mitogen-stimulated CD4+, CD4+CD8α+ and CD4-CD8α- T cells by down-regulation of the IL-2 synthesis and increased the percentage of CD4-CD8α- double negative T cells, probably by depressing their ability to express a CD8α marker after activation. The observations implicate potential immunosuppressive activity of nanogold and strong influence of nanoparticles on CD4-CD8α- T cells, the most abundant subpopulation in young animals, suggests its particular effect on a developing immune system.