Search results for "Complement system"
showing 10 items of 157 documents
Prognostic Value of Complement Properdin in Cancer
2021
© 2021 Mangogna, Varghese, Agostinis, Alrokayan, Khan, Stover, Belmonte, Martorana, Ricci, Bulla and Kishore. The complement system is readily triggered by the presence of damage-associated molecular patterns on the surface of tumour cells. The complement alternative pathway provides rapid amplification of the molecular stress signal, leading to complement cascade actvation to deal with pathogens or malignant cells. Properdin is the only known positive regulator of the alternative pathway. In addition, properdin promotes the phagocytic uptake of apoptotic T cells by macrophages and dendritic cells without activating the complement system, thus, establishing its ability to recognize “altered…
Seminal plasma-induced suppression of the respiratory burst of polymorphonuclear leukocytes and monocytes.
1984
Summary: Based on recent findings indicating suppression of lymphocytic functions by seminal plasma (SP) we tested the effects of SP from men with normo- and oligozoospermia (n = 7, each) on the generation of luminol-enhanced chemiluminescence (CL) of polymorphonuclear leukocytes (PMN) and monocytes (Mo) stimulated in vitro with zymosan. We found a complete suppression of CL of PMN and Mo by undiluted SP's, 1,000-fold dilutions still induced ≥ 20 percent inhibition. There was no difference between normo- and oligozoospermic men in inhibition of CL both with PMN and Mo. Protein concentrations of SP's were closely the same; all SP were free of the complement components C4 and C3c. After dialy…
Development of systemic lupus erythematosus in a patient with selective complete C1q deficiency
1997
A 7-year-old male with recurrent erythematous and desquamated skin lesions and respiratory infections was diagnosed as selective complete C1q deficiency following detailed studies of the complement system. His asymptomatic sister also had selective complete C1q deficiency. During a follow up period of 3 years, his skin lesions persisted, he suffered from recurrent bronchopneumonias and glomerulonephritis developed. Renal function deteriorated with the appearance of anti-DNA antibodies. Renal biopsy was consistent with systemic lupus erythematosus. The patient was treated with immunosuppressive drugs, but died of renal failure. It is postulated that in this patient defective clearance of ant…
Complement activation product C4d in oral and oropharyngeal squamous cell carcinoma
2015
OBJECTIVE: Complement C4d-containing fragments have been proposed as diagnostic markers for lung cancer. The purpose of this study was to evaluate the presence of C4d in oropharyngeal (OPSCC) and oral (OSCC) squamous cell carcinomas. SUBJECTS AND METHODS: C4d staining was analyzed by immunohistochemistry in 244 OPSCC surgical specimens. C4d levels were quantified by ELISA in resting saliva samples from 48 patients with oral leukoplakia and 62 with OSCC. Plasma samples from 21 patients with leukoplakia and 30 with oral carcinoma were also studied. RESULTS: C4d staining in OPSCC specimens was associated with nodal invasion (P = 0.001), histopathologic grade (P = 0.014), disease stage (P = 0.0…
Distinct Roles of Classical and Lectin Pathways of Complement in Preeclamptic Placentae
2022
Pre-eclampsia is a pregnancy complication characterized by defective vascular remodeling in maternal decidua responsible for reduced blood flow leading to functional and structural alterations in the placenta. We have investigated the contribution of the complement system to decidual vascular changes and showed that trophoblasts surrounding unremodeled vessels prevalent in preeclamptic decidua fail to express C1q that are clearly detected in cells around remodeled vessels predominant in control placenta. The critical role of C1q is supported by the finding that decidual trophoblasts of femaleC1qa-/-pregnant mice mated toC1qa+/+male mice surrounding remodeled vessels express C1q of paternal …
Research on complement: old issues revisited and a novel sphere of influence
2003
Immunology in recent years has taken a somewhat surprising turn, expressed by a renewed interest in innate immunity. Especially intriguing is the regulatory role exerted by the innate components on the adaptive response, with Toll receptors and complement components being the most investigated. This function has been firmly established for complement protein CR2 (CD21) as part of the BCR co-receptor CD19/CD21/CD81. New findings are now providing a broader picture of complement and its tuning of the immune response; for example, complement proteins have been implicated in the control of T-cell-mediated responses. We will review some of these data here and summarize new discoveries in areas o…
Effetti dell'esposizione in vitro al cloruro di metilmercurio Sulle risposte immunitarie di Dicentrarchus labrax.
2008
This study shows that high methylmercury concentrations are cytotoxic for Dicentrarchus labrax leucocytes, whereas subletal concentrations affect leucocyte phagocytosis and cells morphology in a dose dependent fashion. Although the serum hemoagglutinating activity was not inhibited by the metal, the activity of purified serum F-lectin fraction and mucus was significantly decreased by relevant methylmercury concentrations.
Activation of the lectin pathway in murine lupus nephritis.
2004
In systemic lupus erythematosus (SLE), hypocomplementaemia and complement deposition have been described both in man and in experimental models. A major involvement of the classical pathway of complement activation has been demonstrated in this disease, however relatively little is known about the involvement of the lectin pathway. Therefore in the present study we have analyzed the activity of all three pathways of complement activation in murine models of SLE. In the mouse, MBL is expressed in two forms, namely MBL-A and MBL-C. In the present study young and old MRL-lpr and control MRL+/+ mice were compared for the levels of complement activity with specific attention for the lectin pathw…
Role of murine macrophages and complement in experimental campylobacter infection
1988
Summary. The roles of macrophages and the complement system as potential host defence mechanisms in mice against campylobacter infection were studied in vivo, by depleting the murine serum-complement or the phagocytic cells. Macrophage-depletion was performed by intraperitoneal (i.p.) injection of silica dust, Liquoid or dextran sulphate. During 5 days after infection, such mice showed a significant increase in mortality, compared with controls. In contrast, mice that were previously decomplemented by i.p. injection of Cobra Venom Factor showed no significant increase in mortality. The results with combined macrophage depletion and decomplementation did not differ from those with macrophage…
Complement lysis: a hole is a hole.
1991
recent experimental advances 21, it is now possible to produce MACs with a precise molecular composition 7 for better designed experiments. In my judgement, however, it will always be problematic to propose a single unifying mechanism for MAC action simply because MAC effects are not uniform. The reason for attempting to classify MACs as leaky patch or channel formers is a desire to wield Occam's razor and carve out the simplest unifying theory. But this razor often cuts one's throat, especially when it comes to immunological processes. A system that degranulates platelets, 'kills' such widely diverse targets as artificial liposomes, 'dead' viruses and erythrocytes, metabolically active cel…