Low cord blood pneumococcal antibody concentrations predict more episodes of otitis media.

OBJECTIVE: To determine if cord blood anticapsular polysaccharide pneumococcal IgG antibody concentration was related to the number of otitis media (OM) and acute OM episodes during the first year of life. DESIGN: Prospective study following infants from birth to 24 months. SETTING: Health maintenance organization. PATIENTS: The study population consisted of 415 infants whose mothers volunteered for the study during pregnancy. Cord blood samples were collected and infants were followed up for OM in the health maintenance organization. Ninety-seven percent of the infants were white, 49% male, 3% from households with annual incomes of less than $20 000, and 30% from households with annual incomes of more than $60 000. MAIN OUTCOME MEASURE: Number of physician-diagnosed OM episodes, including both OM with effusion and acute OM, and acute OM episodes from birth to 12 months. RESULTS: With univariate analysis, low cord blood antibody concentrations against serotypes 3 and 19F predicted more acute OM episodes (P =.04 and P =.05, respectively), and low antibody concentrations against serotypes 19F and 23F predicted more OM episodes (P =.04 and P =.05, respectively) over the first year of life. With Poisson regression, which adjusted for variables related to the recurrence of OM and having low cord blood antibody concentrations, serotype 19F remained significantly related to the number of OM episodes (relative risk for lowest quartiles vs upper 3 quartiles 1.23; 95% confidence interval, 1.02-1.50; P =.03). CONCLUSIONS: Low cord blood antibody concentrations to serotype 19F predicted more OM episodes over the first 12 months of life. These results suggest the potential benefit of maternal immunization to raise neonatal antipolysaccharide pneumococcal antibody concentration and delay the onset and reduce the number of OM episodes.

A divalent major histocompatibility complex/IgG1 fusion protein induces antigen-specific T cell activation in vitro and in vivo.

Activation of antigen-specific T cell clones in vivo might be possible by generating soluble MHC molecules; however, such molecules do not induce effective T cell responses unless cross-linked. As a first step in generating a soluble MHC molecule that could function as an antigen-specific immunostimulant, the extracellular domains of the murine H-2Kb MHC class I molecule were fused to the constant domains of a murine IgG1 heavy chain, resulting in a divalent molecule with both a TCR-reactive and an Fc receptor (FcR)-reactive moiety. The fusion protein can be loaded with peptide and can induce T cell activation in a peptide-specific, MHC-restricted manner following immobilization on plastic wells or following cross-linking by FcR+ spleen cells. The fusion protein induces partial T cell activation in vivo in a mouse transgenic for a TCR restricted to H-2Kb. This fusion protein molecule may be useful to study peptide-MHC interactions and may provide a strategy for boosting in vivo antigen-specific T cell responses, such as to viral or tumor antigens.

Autoantibodies produced spontaneously by young 1pr mice carry transforming growth factor beta and suppress cytotoxic T lymphocyte responses.

Young MRL/MPJ-lpr (lpr) mice 8-12 wk old challenged with alloantigen had significantly lower specific cytolytic T lymphocyte (CTL) responses than control MRL/MPJ +/+ mice. Serum from lpr mice compared with serum from ++ or normal C3H mice powerfully suppressed CTL responses in mixed lymphocyte cultures (MLC); absorbing lpr serum on protein G, adding antibody against transforming growth factor beta (TGF-beta) to cultures or dissociating immunoglobulin G (IgG) and TGF-beta before additions to cultures prevented suppression. Apparently autoantibody, similar to IgG produced by normal mice in response to immunization, carries TGF-beta which suppresses CTL responses in vivo and in vitro.