Pregnancy-associated changes in oligomannose oligosaccharides of human and bovine uromodulin (Tamm-Horsfall glycoprotein).

The urinary glycoprotein uromodulin (Tamm-Horsfall glycoprotein) exhibits a pregnancy-associated ability to inhibit antigen-specific T cell proliferation, and the activity is associated with a carbohydrate moiety [Muchmore and Decker (1985) Science 229:479-81; Hession et al., (1987) Science 237:1479-84; Muchmore, Shifrin and Decker (1987) J Immunol 138:2547-53]. We report here that the Man6(7)GlcNAc2-R glycopeptides derived from uromodulin inhibit antigen-specific T cell proliferation by 50% at 0.

Bovine serum sialic acid: age-related changes in type and content.

1. The sialic acid content of newborn calf serum (4.8 mumol/ml) is approx.

Immunosuppression, sialic acid, and sialyltransferase of neonatal and maternal bovine serum.

Serum samples of 7 cows from -10 to +10 days following parturition and of 7 calves from 0 to 20 days following birth were tested for the ability to inhibit mitogen-stimulated proliferation of lymphocytes, for cortisol and progesterone concentrations, and for sialic acid and sialyltransferase activity. Calf serum inhibited phytohemagglutinin (PHA)-stimulated proliferation of lymphocytes, with maximal inhibition at 12-24 h following birth, whereas no consistent immunosuppressive activity was detected in the maternal serum. Sialic acid was greatly elevated in calf serum (4.

Sialyltransferase of bovine serum: age- and hormone-related changes.

Sialyltransferase activity of bovine serum with the acceptor asialofetuin exhibits a pH optimum at 6.0-6.5, no divalent cation dependence, and a Km for CMP-sialic acid of 0.

Immunosuppression, sialic acid, and sialyltransferase of bovine serum as a function of progesterone concentration.

Serum samples from progesterone-oestrogen-treated ovariectomized Holstein cows (N = 4) were compared with samples from control ovariectomized Holstein cows (N = 4) to determine the effects of physiological levels (0-6 ng/ml) of circulating progesterone. The average progesterone level in treated animals rose from 1 ng/ml (Day 0) to plateau at 5 ng/ml (Days 12 to 36). Sera from progesterone-oestrogen-treated cows during Days 4 to 10 significantly suppressed stimulation of lymphocytes by phytohaemagglutinin as compared with sera from control cows (P = 0.

Sodium-ion dependence of glycine and lysine transport in chicken erythrocytes genetically selected for high and low leucine transport activity.

Amino acid transport was studied in two lines of chickens, one high and the other low uptake, selected for their ability to transport leucine into erythrocytes. On the basis of the number of mol of substrate transferred, medium Na+ was found to be more effective in stimulating glycine and lysine transport into high line cells than into low line cells. Glycine transport in both lines was stimulated by medium Na+ to a greater degree than was lysine transport.

Developmental changes in amino acid transport in the chicken erythrocyte.

1. Influx of leucine, lysine and glycine was found to be highest in prehatch (day -1) chicken red blood cells and to diminish during posthatch development when tested at two and four weeks of age. 2.

Amino acid transport and intracellular Na+ and K+ content of chicken erythrocytes genetically selected for high and low leucine transport activity.

1. Amino acid transport and intracellular Na+ and K+ content have been studied in two lines of chickens, one high and the other low uptake, selected for their ability to transport leucine into erythrocytes. 2.

Uptake of leucine and lysine in chicken red blood cells of varying density.

1. Reproducible separations of chicken red blood cells into three density ranges have been achieved employing Ficoll density layer centrifugation techniques. 2.

Selective breeding of chickens for erythrocytes with high and low leucine transport activity.

Two lines of chickens, one high and the other low uptake, have been selected for three generations for their ability to transport leucine into erythrocytes. Significant line differences were produced in one generation of selection with further separation resulting in later generations. Selection progress has been exclusively with the high-uptake line, the low line not differing significantly from the control.