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Group B Streptococcus (GBS) is a leading cause of adverse pregnancy outcomes due to invasive infection. This study investigated longitudinal variation in GBS rectovaginal colonization, serum and vaginal GBS capsular polysaccharide (CPS)-specific antibody levels. Non-pregnant women were recruited in the UK and were sampled every 2 weeks over a 12-week period. GBS isolates were taken from recto-vaginal swabs and serotyped by polymerase chain reaction. Serum and vaginal immunoglobulin G (IgG) and nasal immunoglobulin A (IgA) specific to CPS were measured by Luminex, and total IgG/A by ELISA. Seventy women were enrolled, of median age 26. Out of the 66 participants who completed at least three visits: 14/47 (29.8%) women that were GBS negative at screening became positive in follow-up visits and 16/19 (84.2%) women who were GBS positive at screening became negative. There was 50% probability of becoming negative 36 days after the first positive swab. The rate of detectable GBS carriage fluctuated over time, although serum, vaginal, and nasal CPS-specific antibody levels remained constant. Levels of CPS-specific antibodies were higher in the serum of individuals colonized with GBS than in non-colonized, but similar in the vaginal and nasal mucosa. We found correlations between antibody levels in serum and the vaginal and nasal mucosa. Our study demonstrates the feasibility of elution methods to retrieve vaginal and nasal antibodies, and the optimization of immunoassays to measure GBS-CPS-specific antibodies. The difference between the dynamics of colonization and antibody response is interesting and further investigation is required for vaccine development. 70 non-pregnant women were recruited, from which 21 were GBS positive at baseline. GBS recto-vaginal colonisation and capsule polysaccharides specific antibody levels in serum, and in the vaginal and nasal mucosa were followed for three months. Colonisation and GBS serotypes present fluctuated over time. [ABSTRACT FROM AUTHOR]

Autoantibodies to insulin (IAA) are one of the first markers of the autoimmune process leading to type 1 diabetes (T1D). While other autoantibodies in T1D have been studied extensively, relatively little is known about IAA and their binding specificities, especially after insulin treatment is initiated. We hypothesize that insulin antibodies (IA) that develop upon initiation of insulin treatment differ in their epitope specificities from IAA. We analysed insulin antibody binding specificities in longitudinal samples of T1D patients ( n = 49). Samples were taken at clinical diagnosis of disease and after insulin treatment was initiated. The epitope specificities were analysed using recombinant Fab (rFab) derived from insulin-specific monoclonal antibodies AE9D6 and CG7C7. Binding of radiolabelled insulin by samples taken at onset of the disease was significantly reduced in the presence of rFab CG7C7 and AE9D6. rFab AE9D6 competed sera binding to insulin significantly better than rFab CG7C7 ( P = 0·02). Binding to the AE9D6-defined epitope in the initial sample was correlated inversely with age at onset ( P = 0·005). The binding to the AE9D6-defined epitope increased significantly ( P < 0·0001) after 3 months of insulin treatment. Binding to the CG7C7-defined epitope did not change during the analysed period of 12 months. We conclude that epitopes recognized by insulin binding antibodies can be identified using monoclonal insulin-specific rFab as competitors. Using this approach we observed that insulin treatment is accompanied by a change in epitope specificities in the emerging IA. [ABSTRACT FROM AUTHOR]

Autoantibodies to insulin are often the first autoantibodies detected in young children with type 1 diabetes and can be present before the onset of clinical diabetes. These autoantibodies and their epitopes are, however, not well characterized. We explored the use of monoclonal antibodies and their recombinant Fab as reagents for epitope analysis. In this study we cloned and characterized the recombinant Fab of the insulin-specific monoclonal antibody CG7C7. We found the epitope of this antibody to be located predominantly at the A-chain loop of the insulin molecule. The recombinant Fab was then used to compete for insulin binding against insulin autoantibodies present in sera from patients with type 1 or type 1·5 diabetes. In competition experiments with sera positive for autoantibodies to insulin the recombinant Fab significantly reduced the binding to[125I]-insulin by sera of type 1 (n = 35) and type 1·5 diabetes[latent autoimmune diabetes in adults (LADA)] (n = 14) patients (P < 0·0001). We conclude that competition between insulin-specific monoclonal antibodies or their recombinant Fab and insulin autoantibodies should prove useful in the epitope analysis of autoantibodies to insulin. [ABSTRACT FROM AUTHOR]

We have studied the effects of various pharmacological mediators on human NK cell activity. Prostaglandin E2 (PGE2) inhibits NK cell activity in a dose-dependent fashion, whereas PGF2α has no significant effect over the same concentration range. Histamine at high doses (10-4 M) induced a small but significant inhibition of NK cell activity which was mimicked by both H1 and H2 specific histamine receptor agonists. Inhibition of endogenous prostaglandin production by indomethacin did not alter NK cell activity. Inhibition of NK activity by cAMP but not cGMP analogues, together with other data presented suggests that the mechanism of PGE2-induced inhibition of NK cell activity is not due to impairment of effector cell movement or effector:target cell interaction, but through the adenylate cyclase system which modulates the killing process. [ABSTRACT FROM AUTHOR]