Biomedical subjects

M Nemec

Publications and source records attributed to M Nemec.

31 records · Page 2Linked to original sources

PubMed1992

Protective local and systemic antibody responses of swine exposed to an aerosol of Actinobacillus pleuropneumoniae serotype 1.

The isotype-specific antibody responses in serum and in nasal and pulmonary lavage fluids of swine following aerosol immunization with an attenuated strain of Actinobacillus pleuropneumoniae serotype 1, strain CM5A, was investigated. The presence of immunoglobulin G (IgG), IgA, and IgM with specificities for capsular polysaccharide, lipopolysaccharide, and hemolysin was determined by enzyme-linked immunosorbent assay by using purified antigens. Strain CM5A induced serum antibodies of each isotype to the three antigens. The serum antibody response was sustained and typical of persistent antigenic stimulation. The specific IgM response decreased and the specific IgG response increased after challenge with strain CM5. IgA specific for the three antigens was detected in nasal secretions from all immune pigs, whereas specific IgG could only be detected in samples contaminated with blood. Both IgA and IgG specific for each of the antigens were detected in pulmonary lavage samples. There was no significant increase in specific IgA in nasal secretions; however, levels of lipopolysaccharide-specific and hemolysin-specific IgG and IgA in pulmonary secretions rose after aerosol challenge with strain CM5. Passive transfer of immune swine serum resulted in protection against pleuropneumonia and in levels of specific serum IgG which were similar to those in actively immunized pigs. It is concluded that specific serum IgG antibodies are important in protection from porcine pleuropneumonia.

Actinobacillus pleuropneumoniae↗

PubMed1990

Effect of vitamin E and selenium supplementation on some immune parameters following vaccination against brucellosis in cattle.

Twenty-four 7-mo-old beef heifers (Charolais Simmental cross), weighing 213 kg, were used to determine the effect of vitamin E (VitE) and(or) selenium (Se) supplementation on the humoral response to a standard dose of Brucella abortus strain 19 vaccine and on the levels of naturally occurring immunoglobulins (Ig) to several antigens. The treatments were as follows: Group 1, no supplement; Group 2, supplementation with 6 g of elemental Se; Group 3, supplementation with 1,400 IU/d of VitE; and Group 4, Se and VitE supplements combined. There were no significant differences in anti-B. abortus IgG1, IgG2, or IgM antibody levels due to Se, VitE or Se/VitE treatments; the concentrations of IgA antibody were too low to be measured with the ELISA test used. Statistical analysis revealed that the levels of total and IgM natural antibody to Salmonella typhimurium were higher in Group 3. Perhaps VitE supplementation given in conjunction with B. abortus vaccine enhanced the production of antibody to S. typhimurium in several animals whose humoral system had been activated by previous exposure to this organism.

Animals↗

PubMed1982

Spin-labeled phorbol esters and their interaction with cellular membranes.

A series of homologous spin-labeled fatty acid analogs of the type 12-O-FASL (n,m)-phorbol-13-acetate [(n,m)PA] of 12-O-tetradecanoylphorbol-13-acetate (TPA) with variable chain length N of the fatty acid moiety and various positions of the nitroxide group were synthesized. Their irritant doses 50 (ID50) on the ear and their initiation-promoting activities on the back skin of NMRI mice were determined. The irritancy 1/ID50 of the (n,m)PA follows the simple linear relation ln(1/ID50) = alpha N + beta. In an "equilibrium" approach, the electron paramagnetic resonance (EPR) spectra measured in absence and in presence of erythrocytes (E) were used to determine the partition coefficients KM,0 between the erythrocyte membrane (M) and the extracellular solution (o). The KM,0 depend on the chain length N of the fatty acid moieties following the equation ln KM,0 = aN + b and show that the (n,m)PA are accumulated preferentially in the erythrocyte membrane. In a "kinetic" approach, the decay rate J(t)/J(o) of the EPR signal intensity of (n,m)PA molecules in absence and in presence of equilibrated E was measured during oxidation with ferricyanide and reduction with ascorbate, respectively. From the data obtained by the "kinetic" approach, a "two-compartmental model" is shown to be the most simple approximation to describe the system, in which finite concentrations of the (n,m)PA are postulated for the extracellular and the membrane compartment only. EPR data indicate that generally the (n,m)PA are buried with their acyl chain in the E membrane with the phorbol moiety close to the outer membrane surface. Apparently only in case of (1,12)PA is the acyl chain long enough to be anchored in the lipid layer of the membrane in a way similar to the tetradecanoyl residue of TPA. A possible relationship with biological activities is discussed.

Animals↗

PubMed1982