Navegando por Palavras-chave "IgG antibodies"

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    Acquisition of Serum Antibodies Reactive With Enterohemorrhagic Escherichia coli Virulence-Associated Factors by Healthy Brazilian Children and Adults
    (Lippincott Williams & Wilkins, 2009-12-01) Palmeira, Patricia; Carbonare, Solange B.; Guth, Beatriz E. C. [UNIFESP]; Carbonare, Cristiane B.; Pontes, Gerlandia N.; Tino-De-Franco, Milene; Zapata-Quintanilla, Lucy B.; Carneiro-Sampaio, Magda; Universidade Federal de São Paulo (UNIFESP); Butantan Inst
    Background: Patients with hemorrhagic colitis or hemolytic uremic syndrome due to enterohemorrhagic Escherichia coli (EHEC) develop serum IgM and IgG response to lipopolysaccharide (LPS) and to virulence factors such as intimin. the small numbers of cases of diarrhea associated with EHEC strains in Brazil suggests a pre-existing immunity probably due to previous contact with diarrheagenic E. coli. Our aim was to evaluate the development of the serum antibody repertoire to EHEC virulence factors in Brazilian children and adults.Methods: Serum IgM and IgG antibodies were determined by enzyme-linked immunosorbent assay with LPS O111, LPS O26, and LPS O157 in 101 children between 2 months and 10 years of age and in 100 adult sera, by immunoblotting with protein membrane extracts and purified beta intimin; the ability of adult sera to neutralize Shiga toxin2 was also investigated.Results: Children older than 24 months had IgM concentrations reactive with the 3 LPS equivalent to those seen in the adult group, and significantly higher than the group of younger children (P < 0.05). Anti-O26 and anti-O157 LPS IgG concentrations were equivalent between the 2 groups of children and were significantly different from the adult group (P < 0.05). the anti-O111 LPS IgG levels in older children were intermediate between the younger group, and adults (P < 0.05). Immunoblotting revealed strong protein reactivity, including the conserved and variable regions of beta intimin and more than 50% of the adult samples neutralized Shiga toxin 2.Conclusions: Our results demonstrate an increasing anti-LPS and antiprotein antibody response with age, which could provide protection against EHEC infections.
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    Placental transfer of naturally acquired, maternal cytomegalovirus antibodies in term and preterm neonates
    (Wiley-Blackwell, 2003-02-01) Mussi-Pinhata, M. M.; Pinto, PCG; Yamamoto, A. Y.; Berencsi, K.; Souza, CBS de; Andrea, M.; Duarte, G.; Jorge, S. M.; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP); Wistar Inst Anat & Biol
    Maternal antibodies may protect the fetus and neonate against severe forms of CMV-caused disease, therefore this study investigated the efficiency-of the placental transfer of naturally acquired, maternal total anti-cytomegalovirus (CMV) IgG and neutralizing antibodies at different gestational ages. the study was conducted on 182 healthy CMV-seropositive Brazilian mothers and their 196 infants who were not infected congenitally with CMV, as determined by CMV detection in urine. the study groups were composed of 44 infants aged 28-30 weeks; 51 infants aged 31-33 weeks; 62 infants aged 3436 weeks, and 39 infants of gestational age greater than or equal to37 weeks. Quantitative detection of total CMV IgG was carried out using EIA and virus neutralizing titers were determined by a microneutralization assay in sera from mothers and infants. CMV IgG levels and neutralizing titers of the infants correlated with maternal levels (r = 0.873 and r = 0.841, respectively). the efficiency of placental transfer of these antibodies was enhanced significantly as gestation progressed until 3436 weeks, when values similar to those of fullterm infants (90-100%) were found. Transfer ratios were significantly higher for neutralizing compared to total CMV IgG antibodies at gestational age 31-33 weeks (100% vs. 84%, respectively) and at gestational age 28-30 weeks (75% vs. 60%, respectively). We conclude that placental transfer of naturally acquired maternal CMV neutralizing and total CMV IgG antibodies are similarly efficient above 34 weeks of gestational age. At less than 34 weeks of gestational age, transfer of neutralizing antibodies may be favored and these antibodies reach the neonatal serum of 99% of these premature infants.