Effects of the B-cell activators lipid A and dextran sulphate on the antibody response to sheep red blood cells in piglets.

The in vivo effects of Lipid A and dextran sulphate on the antibody response to the thymus-dependent antigen SRBC in piglets are reported. No alteration of the low primary antibody response was observed with any of the B-cell activators. However, both substances induced an increase in antibody titre after secondary challenge with the antigen, which was shown to be of the IgG class. An activation of immunological memory in the absence of primary antibody response is suggested.

Development of peripheral B and T lymphocytes in piglets.

The percentage of B and T lymphocytes in the peripheral blood of piglets during their first 35 days of life was estimated by means of the immunofluorescence-labelled anti-L chains sera and the spontaneous E-rosette techniques. The mean values obtained for adult pigs PBL were 23.8 +/- 10.2% of B and 38.0 +/- 8.4% of T lymphocytes. The piglets showed a linear increase for the B lymphocytes starting from a mean value of 4% observed for the newborns. The trend of the T lymphocytes was represented by a bimodal curve. It starts for newborns at 3% and shows a change in shape by the 10th day. It is suggested that the piglets have adult levels of B and T lymphocytes by the time of weaning.

Isolation of porcine colostral immunoglobulins and preparation of monospecific anti-gamma, anti-alpha, and anti-mu chain antibodies using agarose-linked immunosorbents.

A simple method for the simultaneous isolation of IgG2, IgG1, IgA and IgM from porcine colostral whey is described. It makes use of DEAE-cellulose chromatography followed by repeated Sepharose 6B exclusion chromatography after the removal of fat, casein and lipoproteins, Fused rocket immunoelectrophoresis is used to show the elution patterns of each immunoglobulin class. In addition, the prepation of monospecific anti-gamma, anti-alpha and anti-mu sera by means of agarose-linked immunoadsorbents is also described.

Purification of arginases from human-leukemic lymphocytes and granulocytes: study of their physicochemical and kinetic properties.

Arginase has been isolated from granulocytes of a patient with chronic myelocytic leukemia and from lymphocytes of a patient with chronic lymphocytic leukemia and both enzymes have been purified to apparent homogeneity. The purification procedure employed acetone extraction, ammonium sulfate precipitation, DEAE-cellulose and CM-Sephadex chromatography and gel filtration on Bio-Gel A 1.5m. Both enzymes appear to be metalloenzymes, and to have molecular weights of about 120 000. Studies with the dissociated enzymes suggest that the subunit molecular weight is about 37 000, in agreement with a tetrameric aggregate structure of the native enzymes. Human leukemic granulocyte and lymphocyte arginases are strongly basic proteins with pI values between 9.25 and 9.35. Their free -SH groups enabled them to be linked to organomercurial-agarose. The kinetic properties estimated for both enzymes showed an optimum pH of 8.5, and an optimal MnCl2 concentration of 0.01 M. The Km for L-arginine is 2.7-3.1 mM and L-ornithine exhibits a mixed type of inhibition, with a Ki of 15.5-15.7 mM.