RESUMO
In the present study, we characterized the allelic and haplotypic profile of the genes HLA-A, -B, -C and -DRB1 (PCR-SBT) in a population sample of 144 highly admixed individuals, coming from rural communities in Brazil (Quilombos from Vale do Ribeira, in the State of São Paulo). Furthermore, we identified three individuals with a new null allele in the HLA-C gene (HLA-C(∗)02:105N), associated with the haplotype HLA-A(∗)80: 01â¼B(∗)18: 01:01Gâ¼DRB1(∗) 07:01.
Assuntos
Antígenos HLA-A/genética , Antígenos HLA-B/genética , Antígenos HLA-C/genética , Cadeias HLA-DRB1/genética , População Rural , Feminino , Frequência do Gene , Genética Populacional , Haplótipos , Humanos , Masculino , Polimorfismo GenéticoRESUMO
Methods to impute HLA alleles based on dense single nucleotide polymorphism (SNP) data provide a valuable resource to association studies and evolutionary investigation of the MHC region. The availability of appropriate training sets is critical to the accuracy of HLA imputation, and the inclusion of samples with various ancestries is an important pre-requisite in studies of admixed populations. We assess the accuracy of HLA imputation using 1000 Genomes Project data as a training set, applying it to a highly admixed Brazilian population, the Quilombos from the state of São Paulo. To assess accuracy, we compared imputed and experimentally determined genotypes for 146 samples at 4 HLA classical loci. We found imputation accuracies of 82.9%, 81.8%, 94.8% and 86.6% for HLA-A, -B, -C and -DRB1 respectively (two-field resolution). Accuracies were improved when we included a subset of Quilombo individuals in the training set. We conclude that the 1000 Genomes data is a valuable resource for construction of training sets due to the diversity of ancestries and the potential for a large overlap of SNPs with the target population. We also show that tailoring training sets to features of the target population substantially enhances imputation accuracy.
Assuntos
Alelos , Biologia Computacional/métodos , Genética Populacional , Antígenos HLA/genética , Polimorfismo de Nucleotídeo Único , Software , Brasil , Bases de Dados Genéticas , Genoma Humano , Estudo de Associação Genômica Ampla , Humanos , Reprodutibilidade dos Testes , NavegadorRESUMO
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.
Assuntos
Anticorpos Antibacterianos/sangue , Proteínas da Membrana Bacteriana Externa/imunologia , Escherichia coli Êntero-Hemorrágica/imunologia , Proteínas de Escherichia coli/imunologia , Lipopolissacarídeos/imunologia , Adesinas Bacterianas/imunologia , Adulto , Animais , Anticorpos Antibacterianos/imunologia , Brasil , Criança , Pré-Escolar , Chlorocebus aethiops , Reações Cruzadas/imunologia , Escherichia coli Êntero-Hemorrágica/patogenicidade , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Lactente , Estatísticas não Paramétricas , Células VeroRESUMO
We studied the levels of immunoglobulins in colostrum, milk and sera from two common variable immunodeficiency (CVID) mothers (M1 and M2), and in sera from their newborn infants. During pregnancy they continued intravenous immunoglobulin therapy (IVIG). Antibody levels from maternal and cord blood collected at delivery and colostrum and milk, collected on the 3rd and 7th post-partum days, respectively, were analyzed. Although cord/maternal blood ratios of total immunoglobulins and subclasses, as well as specific antibodies differed between M1 and M2, both showed good placental transfer of anti-protein and anti-polysaccharide antibodies, despite lower cord/maternal blood ratios in M2. Anti-Streptococcus pneumoniae antibody avidity indexes were similar between paired maternal and cord serum. Both mothers' colostrum and milk samples showed only traces of IgA, and IgM and IgG levels in colostrum were within normal range in M1, whereas M2 presented elevated IgG and low IgM levels, when compared with healthy mothers. The study of colostrum and milk activity showed that they strongly inhibited enteropathogenic Escherichia coli adhesion in vitro. CVID patients must be informed about the relevance of regular IVIG administration during pregnancy, not only for their own health but also for their immune immature offspring. Breast-feeding should be encouraged as colostra from these CVID patients strongly inhibited E. coli adhesion to human epithelial cells thus providing immunological protection plus nutritional and psychological benefits for the infant.
Assuntos
Anticorpos/imunologia , Imunodeficiência de Variável Comum/terapia , Imunidade Materno-Adquirida , Imunoglobulinas Intravenosas/imunologia , Leite Humano/imunologia , Placenta/imunologia , Complicações na Gravidez/imunologia , Adulto , Animais , Aleitamento Materno , Colostro/imunologia , Imunodeficiência de Variável Comum/imunologia , Feminino , Sangue Fetal/imunologia , Humanos , Imunoglobulinas/classificação , Imunoglobulinas/imunologia , Imunoglobulinas Intravenosas/administração & dosagem , Imunoglobulinas Intravenosas/uso terapêutico , Recém-Nascido , Masculino , Gravidez , Adulto JovemRESUMO
The nocturnal surge of melatonin is the endocrine expression of the circadian system and is essential for organizing the timing of various endogenous processes. Previous works suggest that, in the beginning of a defense response, the increase in circulating tumor necrosis factor-alpha (TNF-alpha) leads to a transient block of nocturnal melatonin production and promotes a disruption of internal time organization. In the present paper, the concentration of melatonin and cytokines [TNF-alpha, interferon-gamma (IFN-gamma), interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12] in the colostrum (postdelivery day 3) and in the milk (postdelivery days 10, 15, 20 and 30) obtained at midday and midnight from mothers who gave birth by vaginal or cesarean section were compared. The nocturnal melatonin surge observed 3 days after vaginal delivery was absent after cesarean section. IL-12 presented no daily variation in either case, while daily variations in IFN-gamma, IL-10, IL-4 and IL-5 were observed after vaginal delivery and cesarean section. On the other hand, the increase in TNF-alpha after cesarean section resulted in suppression of the nocturnal melatonin surge. Daily variation of IL-2 was only observed after recovery of the nocturnal melatonin surge, 30 days after cesarean section. The present paper supports the hypothesis of a cross-talk between the pineal gland and the immune system, which could represent a putative immune-pineal axis.
Assuntos
Citocinas/metabolismo , Melatonina/metabolismo , Glândula Pineal/imunologia , Fator de Necrose Tumoral alfa/metabolismo , Adolescente , Adulto , Cesárea , Ritmo Circadiano , Colostro/imunologia , Colostro/metabolismo , Citocinas/imunologia , Feminino , Humanos , Interferon gama/imunologia , Interferon gama/metabolismo , Interleucina-10/imunologia , Interleucina-10/metabolismo , Interleucina-12/imunologia , Interleucina-12/metabolismo , Interleucina-2/imunologia , Interleucina-2/metabolismo , Interleucina-4/imunologia , Interleucina-4/metabolismo , Interleucina-5/imunologia , Interleucina-5/metabolismo , Leite Humano/imunologia , Leite Humano/metabolismo , Gravidez , Fator de Necrose Tumoral alfa/imunologiaRESUMO
A large number of data show that melatonin has immunomodulatory properties and is produced by immunocompetent cells; also, some evidence suggests a 'feedback' of the activated immune system on the pineal gland. In this paper, we studied immune-pineal interactions in colostrum obtained from healthy puerperae and mothers with mastitis taking into account that, (a) melatonin levels in milk reflects pineal activity and (b) colostrum quiescent mononuclear and polymorphonuclear phagocytes from healthy mothers in culture are adequate for evaluating the ability of immunocompetent cells to produce melatonin. Here we compared the diurnal and nocturnal melatonin levels in colostrum from healthy puerperae and mothers with mastitis; this is a unique noninvasive model for determining pineal activity in the proinflammatory phase of a defense response. In addition, we determined the 'in vitro' production of melatonin by colostrum immunocompetent cells stimulated by enteropathogenic Escherichia coli or zymosan. Suppression of nocturnal melatonin rise in mothers with mastitis was highly correlated with increased tumor necrosis factor-alpha (TNF-alpha) secretion. This result, interpreted taking into account the presence of the transcription factor nuclear factor kappa B in pineal gland, suggest that the proinflammatory cytokine can inhibit nocturnal pineal melatonin production. On the other hand, stimulated, but not quiescent, immunocompetent cells secreted in the colostrum produced melatonin in vitro. In addition, this production ceases after bacteria killing. These results suggest that during the response to an injury the production of melatonin can be transiently shifted from an endocrine (pineal) to a paracrine (immunocompetent cells) source.