Cell surface activation of the alternative complement pathway by the fusion protein of measles virus.
Measles virus (MV)-infected cells are activators of the alternative human complement pathway, resulting in high deposition of C3b on the cell surface. Activation was observed independent of whether CD46 was used as a cellular receptor and did not correlate with CD46 down-regulation. The virus itself was an activator of the alternative pathway and was covered by C3b/C3bi, resulting in some loss in infectivity without loss of virus binding to target cells. The cell surface expression of MV fusion (F), but not haemagglutinin, envelope protein resulted in complement activation of the Factor B-dependent alternative pathway in a dose-dependent manner and F-C3b complexes were formed. The underlying activation mechanism was not related to any decrease in cell surface expression of the complement regulators CD46 and CD55. The C3b/C3bi coating of MV-infected cells and virus should ensure enhanced targeting of MV antigens to the immune system, through binding to complement receptors.
Devaux
Patricia
P
Immunité & Infections Virales, CNRS-UCBL UMR 5537, IFR 62 Laennec, Rue Paradin, 69372 Lyon Cedex 08, France.
Christiansen
Dale
D
Immunité & Infections Virales, CNRS-UCBL UMR 5537, IFR 62 Laennec, Rue Paradin, 69372 Lyon Cedex 08, France.
Plumet
Sébastien
S
Immunité & Infections Virales, CNRS-UCBL UMR 5537, IFR 62 Laennec, Rue Paradin, 69372 Lyon Cedex 08, France.
Gerlier
Denis
D
Immunité & Infections Virales, CNRS-UCBL UMR 5537, IFR 62 Laennec, Rue Paradin, 69372 Lyon Cedex 08, France.
D000818:Animals; D015703:Antigens, CD / Q000502:physiology; D016466:CHO Cells; D003179:Complement C3b / Q000502:physiology; D011415:Complement Factor B / Q000502:physiology; D003170:Complement Pathway, Alternative; D006224:Cricetinae; D006801:Humans; D008459:Measles virus / Q000502:physiology*; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins / Q000502:physiology; D014760:Viral Fusion Proteins / Q000502:physiology*
D015703:Antigens, CD; C497857:CD46 protein, human; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins; D014760:Viral Fusion Proteins; D003179:Complement C3b; D011415:Complement Factor B