Isolation and Characterization of M-1 and M-2 Glycoproteins from Bovine, Porcine, and Avian Plasmas

H9N2-specific IgG and CD4+CD25+ T cells in broilers fed a diet supplemented with organic acids

Organic acids have long been known for their beneficial effects on growth performance in domestic animals. However, their impact on immune responses against viral antigens in chickens is unclear. The present study aimed to investigate immunological parameters in broilers immunized with a H9N2 vaccine and/or fed a diet containing organic acids (citric, formic, and lactic acids). We allotted 1-day-old broilers into 4 groups: control (C), fed a diet supplemented with organic acids (O), administered a H9N2 vaccine (V), and fed a diet supplemented with organic acids and administered a H9N2 vaccine (OV). Blood and spleen samples were taken at 2, 7 and 14 d post vaccination (DPV). At 14 DPV, total and H9N2-specific IgG levels were significantly lower in the OV group than in the V group. However, it was intriguing to observe that at 2 DPV, the percentage of CD4+CD25+ T cells was significantly higher in the OV group than in the other groups, indicating the potential induction of regulatory T cells by organic acids. In contrast, at 2 DPV, the percentage of CD4+CD28+ T cells were significantly lower in the OV group than in the other groups, suggesting that CD28 molecules are down-regulated by the treatment. The expression of CD28 on CD4+ T cells, up-regulated by the stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin (Iono), was inhibited upon organic acid treatment in OV group. In addition, the proliferation of lymphocytes, stimulated with formalin-inactivated H9N2, was significantly higher in the V group than in the OV group. Alpha 1-acid glycoprotein (AGP) production was significantly lower in the OV group than in the V group, suggesting that the organic acids inhibited the inflammation caused by the vaccination. Overall, induction of regulatory CD4+CD25+ T cells, coinciding with the decrease of H9N2-specific antibodies, was observed in broilers fed organic acids.

Plasma alpha 1-acid glycoprotein concentration in broilers: influence of age, sex and injection of Escherichia coli lipopolysaccharide

1. The influence of age, sex and injection of Escherichia coli lipopolysaccharide (LPS) on the plasma concentration of alpha-1 acid glycoprotein (AGP) was determined in broilers using the single radial immunodiffusion method. 2. Plasma AGP concentration increased in the 3 d after hatching, and then stabilised at 240 +/- 33 micrograms/ml up to 14 d of age. 3. No sex-related differences in plasma AGP concentration were observed up to 6 weeks of age. 4. A single injection of 900 micrograms LPS per chick resulted in a 5-fold increase in AGP concentration compared with that in saline-injected chicks. Multiple injections of LPS (200 micrograms/chick every 2 d for 14 d) caused only a 50% increase in AGP concentration.

The physicochemical and chemical properties of alpha 1-acid glycoproteins from mammalian and avian plasmas

We have isolated from the plasma of man, rabbit, pig, rat and chicken alpha 1-acid glycoproteins that show a single band on polyacrylamide gel electrophoresis and a single arc in immunodiffusion. Amino acid and carbohydrate compositions are presented. The human protein is very similar to preparations described by earlier workers and, although significant differences in amino acid composition exist among them, the proteins from the other species are assumed to be analogous to it. Ultra centrifugal studies, despite showing single, fairly symmetrical peaks at high speed, produced evidence for the physical heterogeneity of each protein in agreement with some earlier reports. Although many models consisting of mixtures of components were tested, none was found that fitted adequately all observations on any one of the glycoproteins.