Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1980 Jul;100(1):179-92.

A differential effect of C5a and C5a des Arg in the induction of pulmonary inflammation

A differential effect of C5a and C5a des Arg in the induction of pulmonary inflammation

G L Larsen et al. Am J Pathol. 1980 Jul.

Abstract

Earlier studies have shown that C5 fragments induce an inflammatory reaction when instilled into the rabbit lung. Because C5a is rapidly converted to C5a des Arg in vivo, experiments were performed to determine which fragment was most effective in producing pulmonary inflammation in this animal model. C5a des Arg consistently produced marked inflammation. This was characterized by neutrophil accumulation, edema, hemorrhage, fibrin formation, and damage to alveolar epithelium. The time course of the inflammatory reaction initiated by C5a des Arg showed pulmonary vascular sequestration of neutrophils with no intra-alveolar migration at 30 minutes after injection. By 2 hours, interstitial and alveolar neutrophils were numerous, with the accumulation of neutrophils in the alveoli increasing to a maximum at 6 hours. At 24 and 48 hours, the predominant cells were mononuclear (macrophages). By 120 hours, the lesions were resolving. In contrast, at all doses examined, a similar instillation of C5a induced either no inflammation or a milder, more focal response than C5a des Arg. This inability of C5a to initiate inflammation was not apparently due to the generation of inhibitors, since mixtures of C5a and C5a des Arg were phlogistic. A prolonged, intrapulmonary infusion of C5a (20 minutes), in contrast to a bolus instillation (1 minute), did initiate an inflammatory response, which may reflect the conversion of the C5a to C5a des Arg in the lung. This study points out the inflammatory potential of products of complement activation, particularly of the C5 fragment C5a des Arg, when applied to the airway side of the lungs. This inflammatory response raises the possibility that cleavage of intrapulmonary C5 may play an important role in the initiation of pulmonary inflammation.

PubMed Disclaimer

Similar articles

Cited by

References

    1. J Immunol. 1972 Oct;109(4):896-8 - PubMed
    1. Am Rev Respir Dis. 1974 Dec;110(6 Pt 2):51-7 - PubMed
    1. J Immunol. 1976 Sep;117(3):900-3 - PubMed
    1. J Clin Invest. 1977 Jan;59(1):165-75 - PubMed
    1. J Immunol. 1976 Nov;117(5 Pt 1):1688-94 - PubMed

Publication types