The outer capsid is composed of two structural proteins that determine the rotavirus SB431542 cost serotype classification:

VP7 (glycoprotein, G types) and VP4 (protease-sensitive, P types); both induce neutralizing and protective antibodies. The inner capsid contains the structural protein VP6, which determines the rotavirus serogroup.2 The G9 serotype is frequently detected in humans, and was the second most frequent G type among rotavirus diseases and strains circulating in Latin America and the Caribbean from 1990 to 2009.3 High occurrences of the G9 strain have been detected in Brazil since 1998.4 and 5 Children have an immature immune system, and they depend on the antibodies that they receive from their mothers through the placenta during pregnancy or from the colostrum and breast milk after birth to protect them against infections.6 However, there selleck chemical is no current consensus regarding the role

of maternal antibodies against rotavirus infections. Some studies have reported lower infection rates among infants that have been exclusively breast-fed, when compared to non-breast-fed infants,7 and 8 while other studies have failed to detect any protective effect of breast-feeding.9 and 10 Other reports investigating anti-rotavirus antibodies in human milk have suggested that they may interfere with anti-rotavirus vaccine efficiency by neutralizing the virus particles present in the vaccine before they can multiply within the intestinal cells, thus diminishing the immunological potential of the vaccine.11 and 12 A pentavalent human-bovine rotavirus vaccine containing the serotypes G1, G2, G3, G4, and G9 is currently under development at the Butantan Institute (Brazil) for human use. The aim of this study was to investigate the presence

of SIgA antibodies reactive to the rotavirus serotype G9P[5] in milk samples from Brazilian mothers and their capacity to neutralize virus particles, since it may affect the immunization efficiency of vaccines containing the G9 serotype. The presence of SIgA anti-rotavirus serotype G9P[5] Oxymatrine (human vaccine strain) was analyzed by enzyme-linked immunosorbent assay (ELISA) in 30 milk samples collected from healthy nursing mothers, aged between 19 and 38 years, who had given birth at the Hospital Universitário da Universidade de São Paulo, which mostly attends to patients from lower socio-economic levels, a group that is highly representative of the Brazilian female population. All samples were manually collected in the morning, between breast-feedings. Informed consent from the patients and approval from the Ethics Committee of the Universidade de São Paulo were obtained prior to the collections. The milk samples were collected from nursing mothers with good nutritional and health condition, who were not receiving any medications that might have interfered with the lactation, and had negative serology for HIV, hepatitis B, and syphilis.