Amyloid-β peptide (Aβ) oligomers are pathogenic species of amyloid aggregates in Alzheimer's disease. Like certain protein toxins, Aβ permeabilize cellular membranes, presumably through a pore formation mechanism. Owing to their structural and stoichiometric heterogeneity, the structure these pores remains be characterized. We studied functional Aβ42-pore equivalent, created by fusing Aβ42 olig...

The adaptive immune system constantly remodels its lymphocyte repertoire for better protection against future pathogens. Its ability to improve antigen recognition on the fly relies somatic mutation and selective expansion of B lymphocytes expressing high-affinity receptors. However, this rapid evolution inside an individual appears ineffective, hitting a modest ceiling antigen-binding affinity...

Vaccines have revolutionized modern public health. The effectiveness of some vaccines is limited by the variation in response observed between individuals and across populations. There is compelling evidence that a significant proportion of this variability can be attributed to human genetic variation, especially for those vaccines administered in early life. Identifying and understanding the d...

We determined the sequence types of isolates that caused invasive pneumococcal disease (IPD) prior to routine use of pneumococcal conjugate vaccines (PCV) in South Africa. PCV-13 serotypes and 6C isolates collected in 2007 (1 461/2 437, 60%) from patients of all ages as part of on-going, national, laboratory-based surveillance for IPD, were selected for genetic characterization. In addition, al...

T cells bearing alphabeta receptors recognize antigenic peptides bound to class I and class II glycoproteins encoded in the major histocompatibility complex (MHC). Cytotoxic and helper T cells respond respectively to peptide antigens derived from endogenous sources presented by MHC class I, and exogenous sources presented by MHC II, on antigen presenting cells. Differences in the MHC class I an...

Dioxin-related compounds are associated with teratogenic and mutagenic risks in laboratory animals, and result in adverse pregnancy outcomes. However, there were inconsistent results in epidemiology studies. In view of this difference, we conducted a systematic review and meta-analysis to examine this association and to assess the heterogeneity among studies. Comprehensive literature searches w...

Studies of Mycobacterium leprae, Mycobacterium tuberculosis and Nocardia caviae in comparison with each other and with other Mycobacterium and Nocardia species were performed on the basis of antigen 21 intramolecular heterogeneity. Three different antisera were used: rabbit anti-Mycobacterium smegmatis antiserum, rabbit anti-Nocardia asteroides antiserum, and a lepromatous serum pool. With refe...

BACKGROUND Successful transfusion of platelet refractory patients is a challenge. Many potential donors are needed to sustain human leukocyte antigen matched-platelet transfusion programs because of the different types of antigens and the constant needs of these patients. For a highly mixed population such as the Brazilian population, the pool size required to provide adequate platelet support ...