Immunostimulation of sugar cane extract on neutrophils to Salmonella typhimurium infection in mice.

The aim of this study was to evaluate the immunomodulatory effects of sugar cane extract (SCE) on the biological activities of neutrophils in mice. Six-week-old BALB/c mice were fed 1250 mg/kg of SCE once. The generation, migration and biological functions of neutrophils and the survival rates of the mice in response to Salmonella typhimurium infection were evaluated. The results show that the numbers of both bone marrow cells and neutrophils were significantly increased in response to SCE administration (p < 0.05) compared with controls. The migration, phagocytosis and H2O2 generation of neutrophils were all significantly enhanced in SCE-treated mice (p < 0.05). After challenge with S. typhimurium (lethal dose, 50% (LD50), SCE-treated mice had a 19.2% higher survival rate and milder hepatic lesions than the controls. Additionally, fewer invasive bacteria were recovered from the spleens of SCE-treated mice. In conclusion, our results suggest that SCE has a positive regulatory effect on the biological function of mouse neutrophils that may increase host resistance against bacterial infections.

Adjuvant activity of chicken interleukin-12 co-administered with infectious bursal disease virus recombinant VP2 antigen in chickens.

A recombinant fowlpox virus (rFPV/VP2) expressing infectious bursal diseases virus (IBDV) VP2 gene has been constructed. After purification and identification of rFPV/VP2, the adjuvant activity of the recombinant chicken IL-12 (rchIL-12), synthesized by our previous construct of rFPV/chIL-12, in rFPV/VP2-expressed rVP2 antigen was assessed in one-week-old specific-pathogen free chickens. The results indicated that rchIL-12 alone or rchIL-12 plus mineral oil (MO) co-administered with rVP2 antigen significantly enhanced the production of serum neutralization (SN) antibody against IBDV, compared to those with MO alone. The SN titers in groups receiving rVP2 antigen with MO alone were more inconsistent after vaccination. On the other hand, rchIL-12 significantly stimulated IFN-γ production in serum and in splenocyte cultured supernatant, suggesting that rchIL-12 alone or plus MO significantly induced a cell-mediated immune response. Finally, bursal lesion protection from very virulent IBDV (vvIBDV) challenge in chickens receiving rVP2 antigen with rchIL-12 alone or plus MO was much more effective than that with MO alone at two weeks after boosting. Taken together, rchIL-12 alone augmented in vivo the induction of a primary and also a secondary SN antibody production and a cell-mediated immunity against IBDV rVP2 antigen, which conferred the enhancement of bursal lesion protective efficacy from vvIBDV challenge. These data indicated that a potential for chIL-12 as immunoadjuvant for chicken vaccine development such as IBDV rVP2 antigen.

Effects of sugar cane extract on pseudorabies virus challenge of pigs.

This experiment aimed to evaluate the efficacy of sugar cane extract (SCE) on the modulation of porcine immunity against pseudorabies virus (PrV) infection. Twelve-week-old experimental pigs were fed with SCE (500 mg/kg of body weight per day) for 3 days and challenged with PrV (2 x 10(5) TCID(50)) on the second day. Pigs that were only challenged with PrV and without SCE-treatment served as controls. The leukocyte functional assays were performed on the 7th and 14th day post-PrV challenge. Our results showed a significant enhancement (P<0.05) of natural killer cytotoxicity, lymphocyte proliferation, phagocytic function of monocytes, and interferon-gamma (IFN-gamma) production of CD4(+) and gammadelta T cells in the SCE-treated pigs compared with the controls. In addition, SCE administration reduced the severity of clinical signs and brain lesion in the course of disease in PrV-challenged pigs. SCE-treated pigs showed a 12% growth enhancement compared with untreated controls. SCE administration had an immunostimulating effect on porcine immunity that may subsequently enhance protective activities against PrV infection which may be extensively applied in field for the prevention of infections.