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T L Koppenheffer

Publications and source records attributed to T L Koppenheffer.

11 recordsLinked to original sources
PubMed1999

The complement system of the duck.

Antibody (Ab)-dependent and-independent activation of the duck complement (C') system were studied. Ab-independent C' activity exhibited characteristics similar to those of the mammalian alternative C' pathway (ACP), including the selective lysis of rabbit erythrocytes (RRBC), a requirement for Mg2+, but not Ca2+, depletion of activity by zymosan, and lack of sensitivity to the mammalian C1 inhibitor carrageenan. Measurement of C' activity using antisera against sheep erythrocytes (SRBC) revealed that duck Abs activate C' by a pathway resembling the mammalian classical pathway (CCP) requiring both Ca2+ and Mg2+. Ab-dependent and-independent activities were further distinguishable by their kinetics of lysis and sensitivities to heat. Duck Abs were also found to activate C' in normal and carrageenan-treated serum by a mechanism that requires only Mg2+, and thus resembles the ACP. However, this Ab-dependent ACP-like activity exhibits patterns of ionic strength dependence and ontogeny which are clearly different from those of the conventional ACP and CCP. These findings indicate that duck C' can be activated by three mechanisms: Ab-mediated activation of the CCP, and Ab-mediated and Ab-independent activation of the ACP. Duck Ab responses to SRBC and RRBC were followed by direct agglutination, antiglobulin agglutination, and activation of the CCP and ACP. While the C'-activating abilities of duck anti-SRBC Abs persisted through a 3-month programme of inoculation, the anti-RRBC response lost its ability to activate C' after 2 weeks.

Journal Article↗
PubMed1986

Unusual complement activation properties of serum immunoglobulins of the pigeon Columba livia.

Complement-mediated lysis of mouse erythrocytes (MRBC) by whole pigeon antisera was found to occur in the presence of magnesium ions alone. The underlying basis for this observation was demonstrated to be the ability of IgM antibodies to activate the alternative pathway of pigeon complement, whereas IgG activates a calcium-dependent pathway possessing an unusually low lytic capacity. In addition to differing from the alternative pathway by requiring both calcium and magnesium ions, the calcium-dependent pathway exhibited higher activity at low temperature and more rapid kinetics of haemolysis. The presence of early acting C1 in pigeon serum was inferred by the selective depletion of calcium-dependent activity which occurred as a result of incubating serum containing only calcium ions with MRBC sensitized with IgG. Under the same conditions, MRBC sensitized with IgM failed to deplete complement activity, indicating that C1 does not participate in complement activation by this isotype. Interestingly, the calcium-dependent pathway detected in pigeon serum appears to more closely resemble the C1-bypass pathway rather than the classical pathway of mammalian complement.

Animals↗
PubMed1978

C-type virus-lymphocyte interactions in developing mouse thymus.

The appearance of C-type virus particles in thymus cells of Swiss mouse embryos, 11.5 to 15.5 days post-conception age (PCA), was studied with the electron microscope. In thymic rudiments of all specimens examined, virus particles were seen in epithelial cytoplasm, budding from epithelial cell surfaces and in extracellular spaces. Lymphoid cells were first seen in thymic rudiments of 13.5 days PCA, and did not display virus particles at this stage. At 14.5 days PCA, thymic lymphocytes had localized plasmalemmal thickenings of high electron-density which were adjacent to extracellular virus particles. Viruses appeared to be penetrating thymic lymphocytes by viropexis in embryos of 15.5 days PCA. At this stage, many lymphocytes also had cytoplasmic virus-containing vesicles and viral buds at their surfaces. These observations suggest the possibility that, in embryos, C-type viruses are transmitted horizontally from thymic epithelium to early populations of thymic lymphocytes.

Animals↗
PubMedDate not supplied

The complement system of the marsupial Monodelphis domestica.

The activation requirements and pathways of the serum C' system of the marsupial Monodelphis domestica were characterized using standard hemolytic procedures. The existence of distinct classical and alternative activation pathways was established on the basis of their ionic requirements, hemolytic capacity at different temperatures, kinetics of hemolysis, and differential susceptibility to the classical pathway inhibitor carrageenan. For the most part, the activities of these pathways were influenced by factors and conditions in a manner similar to the way they affect the activity of eutherian complement. These observations provide further support for the idea that Monodelphis domestica would serve as a useful model for comparative immunological studies in mammals.

Animals↗