The aim of this study was to investigate whether diabetes and insulin resistance affect B-1 cells and their production of natural IgM. We found that diabetic db/db mice have Talazoparib nmr lower levels of peritoneal B-1a cells and a decreased

IgM response to pneumococcal immunization and TLR-4 activation. Furthermore, our in-vitro studies showed that glucose in high concentrations reduces B-1 cell IgM secretion and differentiation into antibody-producing cells concurrent with proliferation arrest and increased apoptosis. Specific pathogen-free C57BL/6 mice were purchased from Taconic (Skensved, Denmark). For isolation of peritoneal B-1 cells, male and female C57BL/6 mice were fed a normal chow diet. As a model for insulin resistance, 8-week-old male C57BL/6 mice were assigned randomly to a low glycaemic control diet or a high-fat diet (Harlan

Laboratories, Madison, WI, USA) for 12 weeks. On a caloric basis, the low glycaemic control diet contained 16·8% fat, 60·9% carbohydrate and 22·3% protein (3·3 Kcal/g), whereas the high-fat diet contained 60·3% fat, 21·3% carbohydrate and 18·4% protein (5·1 Kcal/g). The diets contained comparable amounts of vitamins and minerals. Male db/db mice and control mice (+/+ or +/db) on a C57BL/6 background from Jackson Laboratories (Bar Harbor, ME, USA), and db/db and wild-type controls (+/+) on a BKS background from Taconic, were maintained on a normal chow diet. For in-vivo assessment Tamoxifen mw of the effect of TLR-4 agonist, 10–12-week-old db/db mice (on a C57BL/6 background) and controls Axenfeld syndrome were injected intraperitoneally with 0·34 mg/kg of the TLR-4 agonist Kdo2-Lipid A (Avanti Polar Lipids, Inc., Alabaster, AL, USA) or vehicle. For immunization studies, 10–12-week-old db/db mice and controls (on a C57BL/6 or BKS background) and C57BL/6 mice maintained on diets for 3 months were injected intraperitoneally with 11·5 μg of a 23-valent vaccine (Pneumovax; Sanofi Pasteur MSD, Lyon, France), containing 0·5 μg each of 23 types of polysaccharides from S. pneumoniae

or saline. As indicated for each experiment, body weight, plasma insulin, glucose and antibody titres were followed in longitudinal blood samples. Before blood sampling, mice were fasted for 4 h. Plasma glucose in blood samples from fasted, non-anaesthetized animals was determined with a glucose dehydrogenase method by using HemoCue® B-glucose microcuvettes (HemoCue®, Ängelholm, Sweden) and insulin was determined by a mouse insulin enzyme-linked immunosorbent assay (ELISA) (Mercodia, Uppsala, Sweden). Plasma triglycerides and cholesterol were measured using Konelab 20 Autoanalyzer (Thermo Electron Corporation, Vantaa, Finland). All mice were housed in a controlled environment and all experimental protocols were approved by the animal ethical committee in Gothenburg.