Biomedical subjects

H J Wellensiek

Publications and source records attributed to H J Wellensiek.

3 recordsLinked to original sources

PubMed1977

Antibodies to Acholeplasma laidlawii membrane lipids in normal guinea pig serum.

Acholeplasma laidlawii is killed and lysed by fresh normal guinea pig serum (GPS) without additional antibodies. Prior incubation of GPS with whole A. laidlawii organisms abolishes the killing activity of GPS. In the present study it was demonstrated that antibodies are present in normal GPS. The classical pathway, not the alternative pathway, of the complement sequence was activated by these antibodies in fresh normal GPS. The antibodies in GPS belong to the IgG class of immunoglobulins. They are directed predominantly against the membrane phospholipids of A. laidlawii. These antibodies may be induced either by natural infection of guinea pigs with A. laidlawii or by antigenic determinants of other microorganisms of food antigens.

Acholeplasma laidlawii↗

PubMed1976

Complement-mediated killing of Acholeplasma laidlawii by antibodies to various membrane components.

Mycoplasmas are useful models for biochemical studies of the mechanism of complement-mediated killing by antibodies to various membrane components. The purpose of this study was to determine the membrane antigens involved in immune killing of Acholeplasma laidlawii. Antibodies to A. laidlawii membrane total lipids, glycolipids, and phospholipids could be induced in rabbits after injection of reaggregates of the purified lipids with Mycoplasma hominis protein as the carrier. Killing of A. laidlawii membrane lipids were less effective than anti-membrane protein antisera in killing the organisms. Of the antisera to lipid components of A. laidlawii membranes, antiserum to phospholipids showed a more pronounced killing effect than antiserum to glycolipids. The antibodies to A. laidlawii in the rabbit antisera belong predominantly to the immunoglobulin G class of immunoglobulins. Double-diffusion tests in agar indicated that two immunologically reactive proteins are located on the membrane surface.

Acholeplasma laidlawii↗

PubMed1976

Lysis of Acholeplasma laidlawii by antibodies and complement.

Membranes of Acholeplasma laidlawii were used to determine the membrane components involved in immune lysis and to eventually detect enzymatic changes in the membrane components during this reaction. In a previous publication we reported that A. laidlawii can be killed by antibody and complement and that antibodies to membrane proteins are by far more effective than antibodies to membrane lipids in the complement-dependent killing of this organism. In this report we demonstrate that membrane damage occurs after the combined action of antibody and complement. In addition, the cytoplasmic enzyme hexokinase is released during immune killing. As visualized by electron microscopy, the organisms lost their cytoplasm and were transformed into ghosts. In the majority of organisms, tears in the membrane could be seen. Ultrastructural lesions of about 8.0 to 10 nm in diameter were visible when the organisms were incubated with antiserum and complement. 14C-labeled fatty acids were incorporated during growth into A. laidlawii membrane lipids. After incubation of labeled organisms with antiserum and complement, release of radioactive material into the supernatant and changes in the lipid composition were not observeed. Enzymatic degradation of membrane lipids of A. laidlawii during immune lysis was not detected.

Acholeplasma↗