Complement and viral pathogenesis

Department of Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
Virology (Impact Factor: 3.32). 02/2011; 411(2):362-73. DOI: 10.1016/j.virol.2010.12.045
Source: PubMed


The complement system functions as an immune surveillance system that rapidly responds to infection. Activation of the complement system by specific recognition pathways triggers a protease cascade, generating cleavage products that function to eliminate pathogens, regulate inflammatory responses, and shape adaptive immune responses. However, when dysregulated, these powerful functions can become destructive and the complement system has been implicated as a pathogenic effector in numerous diseases, including infectious diseases. This review highlights recent discoveries that have identified critical roles for the complement system in the pathogenesis of viral infection.

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    • "Finally, the complement system, composed of soluble factors and cell surface receptors, blocks viral infection by acting on both the innate and adaptive immune responses. These mechanisms include, enhancing humoral immunity, regulating antibody effector mechanisms, and modulating T cell function (80). "
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    • "The fast activation of the complement system (CS) after a microorganism infects a potential host is an important step in clearance of many pathogens [1]. On the other hand, anaphylatoxins like C3a and C5a, products of the CS cascade, are commonly involved in exacerbated inflammatory reactions that can cause direct harm to the host following infections [2], [3], [4]. "
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    • "Human serum depleted of MBL and L-ficolins that failed to destroy the parasites demonstrated that the lectin pathway is involved to control Giardia infections [52]. Several other pathogens including bacteria and viruses were also shown to activate the lectin pathway [50, 65]. Altogether, the importance of the lectin pathway in pathogen recognition at initial stages of infection is demonstrated. "
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