Age-dependent presence of antibodies in rat dams, capable of conferring protection against group B Streptococcus infection in neonates

A rat model was used to investigate maternal age-dependent resistance on gr oup B Streptococcus (GBS)-induced mortality of the offspring. Offspring fro m young (first time) or older (repeat litters) dams were challenged with GB S. There was an approximate log difference in the dose of GBS required to c ause identical levels of mortality in the two groups. The sera of the dams from both groups were analysed by whole-cell ELISA, and it was demonstrated that sera from the older dams possessed circulating IgG cross-reactive to GBS. Since IgG is transplacentally transferred, we conclude that this is th e method of observed protection. (C) 2001 Federation of European Microbiolo gical Societies. Published by Elsevier Science B.V.. All rights reserved.