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PubMed · 9507637

Mycobacterium tuberculosis and the complement system.

L S Schlesinger
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Abstract

Accumulated evidence to date confirms the importance of the C3-CR pathway in the phagocytosis of pathogenic mycobacteria. Detailed receptor-ligand studies for phagocytosis are creating the framework to test the hypothesis that the entry pathway for these bacteria influences the immediate host cell response and their intracellular fate. These types of study are particularly important for improving our understanding of the outcome of primary infection in humans, where the number of bacilli is presumed to be very low.

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Complement ActivationComplement C2Complement C2aComplement C3Complement Pathway, AlternativeComplement Pathway, ClassicalLeukocytes, MononuclearModels, ImmunologicalMycobacterium tuberculosisOpsonin ProteinsPhagocytosisReceptors, ComplementJournal Article

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L S Schlesinger. 1998. Mycobacterium tuberculosis and the complement system.. https://doi.org/10.1016/s0966-842x(97)01203-1

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PubMed2001

Complement activation products in plasma after heart transplantation in humans.

BACKGROUND: Complement activation has recently been implicated as a contributing factor to early and late allograft dysfunction in cardiac transplantation. The current study was designed to determine whether measurement of plasma complement fragments C4d and SC5b-9 would be useful in detecting acute rejection or accelerated graft atherosclerosis (AGA) in cardiac allograft recipients. METHODS: We measured complement activation products, C4d (classical pathway) and SC5b-9 (terminal pathway), at the time of routine endomyocardial biopsy in heart transplant recipients. Ten patients in the immediate posttransplantation period (0-100 days) and 19 patients more than 6 months after transplantation were studied. RESULTS: No correlation was found between plasma levels of complement activation fragments and the presence of biopsy-proven acute allograft rejection or AGA (assessed by coronary angiography). However, plasma C4d and SC5b-9 were significantly elevated in 9 of 10 and 7 of 10 patients, respectively, in the immediate posttransplantation period. This was followed by progressive decrease in the levels of C4d and SC5b-9 fragments during the first 4-6 weeks after transplantation. CONCLUSION: We conclude that measuring plasma levels of fragments C4d and SC5b-9 is not a useful noninvasive method for detecting acute rejection or AGA after heart transplantation. However, this study provides further evidence that early complement activation after heart transplantation may play a pathogenic role in allograft injury.

Complement Activation↗
PubMed2001

Structure and composition of drusen associated with glomerulonephritis: implications for the role of complement activation in drusen biogenesis.

PURPOSE: The ocular fundi of many patients with membranoproliferative glomerulonephritis type II (MPGN-II) are characterised by the presence of deposits within Bruch's membrane that resemble drusen, hallmark lesions associated with age-related macular degeneration (AMD). Glomerulonephritis (GN)-associated drusen appear at a younger age, however, than do drusen in individuals with AMD. In light of recent evidence that immune-mediated events participate in drusen biogenesis and AMD, we examined the structure and composition of drusen in eyes obtained from human donors with two distinct glomerulopathies, both of which involve complement deposition within glomeruli. These features were compared with those of drusen from patients with clinically documented AMD. METHODS: Eyes obtained from two human human donors diagnosed with membranous and post-streptococcal GN, respectively, were analysed histochemically, immunohistochemically and ultrastructurally. RESULTS: Subretinal pigment epithelial (RPE) deposits in both types of GN are numerous and indistinguishable, both structurally and compositionally, from drusen in donors with AMD. GN-associated drusen exhibit sudanophilia, bind filipin, and react with antibodies directed against vitronectin, complement C5 and C5b-9 complexes, TIMP-3 and amyloid P component. Drusen from the membranous GN donor, but not the post-streptococcal GN donor, reacted with peanut agglutinin and antibodies directed against MHC class II antigens and IgG. The ultrastructural characteristics of these deposits were also identical with those of AMD-associated drusen. CONCLUSIONS: The composition and structure of ocular drusen associated with membranous and post-streptococcal/segmental GN are generally similar to those of drusen in individuals with AMD. In view of the recent data supporting the involvement of complement activation in drusen biogenesis and the pathobiology of AMD, further studies of the biological relationships between AMD and diseases associated with complement activation are warranted.

Complement Activation↗