Complement Factor 9 Deficiency in Serum of Human Neonates
- 1 July 1992
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journal of Infectious Diseases
- Vol. 166 (1) , 53-57
- https://doi.org/10.1093/infdis/166.1.53
Abstract
The serum concentration of complement factor C9 (C9) was 260 ± 47 µg/ml (±SE) in 14 mothers and Escherichia coli O7w:K1:NM to P < .03). Eleven neonatal sera did not kill the bacteria. Supplemental C9 (60 µg/ml) enhanced the bactericidal capacity of 10 neonatal sera. 125I-labeled C9 was deposited onto E. coli by neonatal sera, but less efficiently than by pooled adult sera. Supplemental IgG enhanced 125I-labeled C9 deposition and potentiated the bactericidal activity of exogenous C9. Therefore, neonatal sera contained diminished concentrations of C9 and killed E. coli inefficiently. In neonatal sera, supplemental C9 was deposited onto E. coli and enhanced bactericidal activity. These effects of C9 were potentiated by supplemental IgG.Keywords
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