Selected articles February 2015
Placental transfer of IgG antibodies in twin pregnancies
Placental Transfer of IgG Antibodies Specifik to Klebsiella and Pseudomonas LPS and to Group B Streptococcus in Twin Pregnancies
S. C. L. Stach, M. L. Brizot, A. W. Liao, P. Palmeira, R. P. V. Francisco, M. M. S. Carneiro-Sampaio and M. Zugaib
In a study carried out in the twin clinic of the Department of Obstetrics and Gynecology together with the Pediatric Department of Sao Paulo University it was found that IgG umbilical serum concentration against Klebsiella and Pseudomonas LPS and Group B Streptococcus is associated with specific maternal IgG concentrations and the presence of maternal diabetes.
Sonia Stach is a postgraduate student and the main researcher involved in the study, which is a part of her PhD work.
– Twin pregnancies have a high risk of prematurity and adverse neonatal morbidity, such as admission to intensive care units and infections. Neonatal immunity depends on the acquisition of intrauterine maternal antibodies. Therefore, it is important to understand factors related to IgG maternal transfer in twins to try to develop strategies to improve neonatal prognosis, she says.
Since there is no effective prevention therapies for premature delivery in twin pregnancies, it is important to make an effort to minimize the risk of newborn complications such as lung immaturity and neonatal infections. Strategies, such as mother´s vaccination may be an option in the future.
– The most exciting part of the work was to observe the results that demonstrated factors related to the transfer of immunoglobulins from mother to neonates in twin pregnancies, Sonia Stach concludes.
Characteristics of peritoneal macrophages in NOD mice
Peritoneal Cavity is a Route for Gut-Derived Microbial Signals to Promote Autoimmunity in Non-Obese Diabetic Mice
R. Emani, C. Alam, S. Pekkala, S. Zafar, M. R. Emani and A. Hänninen
In the present study, researchers from Turku, Finland show that peritoneal macrophages in non-obese diabetic (NOD) mice have increased levels of activation markers soon after weaning.
The autoimmune disease type 1 diabetes (T1D) is primarily mediated by T and B cells in the NOD mouse. However, innate immune cells including macrophages also influence this disease. Macrophages play a crucial role in innate immune reactions, and peritoneal macrophages guard the sterility of this compartment. In T1D the gut microbiota and gut immune system appear to contribute to disease pathogenesis. The Finnish group have recently reported elevated free radical production and increased permeability of gut epithelium in NOD mice. This impaired barrier function could lead to bacterial leakage to the peritoneal cavity and to explore the consequences they here characterize peritoneal lavage cells from young, newly weaned NOD mice.
Rohini Emani is a PhD student in the group and the first author of the study who is currently writing her thesis.
– My main responsibilities were to study the levels of activation markers on macrophages and to analyse IRAK-M from the macrophages with Western blotting, she says.
The peritoneal macrophages displayed increased levels of IRAK-M at protein levels after weaning compared to the control strains, and became desensitized to LPS stimulation. This resulted in lower TNF-α production upon in-vitro stimulation with LPS.
In conclusion, the group demonstrate that the number of macrophages in the peritoneal cavity increases rapidly in NOD mice after weaning, ant that these cells show phenotypic characteristics of macrophages exposed to TLR ligands in vivo. In addition, they show enhanced plasma levels of LPS, suggesting translocation of gut microbes or their products into the systemic circulation.
– I enjoyed very much to discuss with my supervisor and colleague the hypothetical model of what causes macrophage influx in the peritoneal cavity and how that may connect to the pathogenesis of islet autoimmunity. The most fun was perhaps to discover that IRAK-M becomes strongly expressed in NOD macrophages after weaning and that the presence of LPS in peritoneal cavity was associated with activation of T cells in pancreatic lymph nodes, Rohini Emani says.