Navegando por Assunto "Anticorpos tipo IgG"

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Acesso aberto (Open Access)
Comparative recognition by human IgG antibodies of recombinant proteins representing three asexual erythrocytic stage vaccine candidates of Plasmodium vivax
(2007-06) BARBEDO, Mayara de Brito; RICCI, Ricardo; JIMENEZ, Maria Carolina Sarti; CUNHA, Maristela Gomes da; YAZDANI, Syed S; CHITNIS, Chetan E; RODRIGUES, Mauricio Martins; SOARES, Irene da Silva
In previous immuno-epidemiological studies of the naturally acquired antibody responses to merozoite surface protein-1 (MSP-1) of Plasmodium vivax, we had evidence that the responses to distinct erythrocytic stage antigens could be differentially regulated. The present study was designed to compare the antibody response to three asexual erythrocytic stage antigens vaccine candidates of P. vivax. Recombinant proteins representing the 19 kDa C-terminal region of MSP-1(PvMSP19), apical membrane antigen n-1 ectodomain (PvAMA-1), and the region II of duffy binding protein (PvDBP-RII) were compared in their ability to bind to IgG antibodies of serum samples collected from 220 individuals from the state of Pará, in the North of Brazil. During patent infection with P. vivax, the frequency of individuals with IgG antibodies to PvMSP119, PvAMA-1, and PvDBP-RII were 95, 72.7, and 44.5% respectively. Although the frequency of responders to PvDBP-RII was lower, this frequency increased in individuals following multiple malarial infections. Individually, the specific antibody levels did not decline significantly nine months after treatment, except to PvMSP119. Our results further confirm a complex regulation of the immune response to distinct blood stage antigens. The reason for that is presently unknown but it may contribute to the high risk of re-infection in individuals living in the endemic areas.
Acesso aberto (Open Access)
Distribuição espacial de anticorpos IgG para Toxoplasma gondii em um estudo soroepidemiológico realizado em bovídeos no estado do Pará
(Universidade Federal do Pará, 2014) OLIVEIRA, Jefferson Pinto de; CASSEB, Alexandre do Rosário; http://lattes.cnpq.br/6525374874057337; FREITAS, José de Arimatéa; http://lattes.cnpq.br/2382745365421156
This study aims to determine the prevalence of antibodies immunoglobulin class G (IgG) specific of this disease in bovine created, by contributing to the understanding of the epidemiology of this zoonosis in the state of Pará. The study was conducted in all Para meso, they were harvested blood samples from animals in 2070, with 1750 and 320 bovine and buffalo, respectively, coming from 52 municipalities and 100 properties, a survey of the epidemiological aspects influencing the onset of the infectious agent. Sera of animals underwent the test of ELISA Kit – Enzyme-Linked Immunosorbent Assay and indirect immunofluorescence - IFA for the detection of specific IgG antibodies to T. gondii cattle and buffalo the Imunodot® company. The animals were considered positive in the IFAT test from the dilution 1:64. It was considered statistically significant difference p 0.005. The buffaloes had higher seropositivity that the bovine, as well as the IFA test was higher than the ELISA test, and Mesoregion more seropositive was the Lower Amazon. There were no significant differences in the frequency of T. gondii, in relation to sex, type of exploitation, but no significant association for age, size of property, number of animals in the property, creation cycle, and the properties that presented greater amount of cats and dogs were the ones that had higher sororreagência the anti - T. gondii.
Acesso aberto (Open Access)
Plasmodium vivax: avaliação da resposta de anticorpos IgG em crianças expostas à malária
(Universidade Federal do Pará, 1997) PINTO, Ana Yecê das Neves; SOUZA, José Maria de; http://lattes.cnpq.br/6459204248879587
An improved knowledge of human antiplasmodial defense mechanisms is partof current strategies against malaria. One of the effective defense mechanisms is the relationship between cytophilic antibodies and monocytes in order to increase the phagocytosis of infected cells. Comparative studies on immunoglobulin patterns have been carried out in immune and semi-immune populations.The present work is a further contribution to the subject and has the objectiveto study the response of IgG antibodies anti-P. vivax (IgG anti-PV), and their cytophilic (lgG1 e IgG3) and non-cytophilic (lgG2) subclasses in 34 outpatient children with malaria by P.vivax. Diagnosis of malaria was established by thick blood films. IgG levels, with their respective subclasses, were identified by indirect fluorescent antibody technique in the children enrolled in the study, during the acute phase and up to ultimate established cure. Patients were divided in 2 groups according to a previous malaria history (primarily infected, n= 28) and patients with history of previous malaria attack (n=6). The geometric means of antibodies IgG anti-PV levels were demonstrated during different periods of sera assessment. The IgG anti-PV levels obtained in the days zero and seven were compared (Student's t test). IgG anti-PV levels were correlated with assexual parasitaemia and the period of sickness, (Spearman's correlation test). A description of clinical features ocurred in both subgroups. Regarding immunoglobulin subclasses, the proportion of positive and negative sera was compared (Exact Fisher's test), in the 2 subgroups with the following results: a significative statistical difference (p=0,027) ocurred in the IgG levels between day zero (D0) and day seven (07), with no correlation with previous malaria history. A descending curve was observed in IgG levels, with mean and variable values respectively of 95,2% (40-2560) on the 60th day, 62,5% (40-320) on the 120th day, and 28% (40-160) on the 180th day after treatment. There was a positive association between the time of sickness and total antibody IgG anti-PV levels in primarily infected patients. The rank order for geometric means of IgG subclasses encountered was: IgG1(598,41) > IgG3 (4,06) > IgG2 (1,42). There were no significative differences in IgG anti-PV subclasses among primarily infected patients and those without previous malaria history. The following conclusions were made: 1) An increase of IgG anti-PV levels was seen between D0 and 07; 2) During the follow up the IgG anti-PV levels showing a gradual tendency to decline: 4,76% of the patients had negative results until 060, 37,5% until 0120, and 71,42% had negative results until 180 days after treatment; 3) There was no association between assexual parasitemia in day zero and antibody levels IgG anti-PV in the first and in the eighth day of treatment; 4) In children with previous malaria attacks the time of sickness evaluation is proporcional to antibody IgG anti-PV levels, and the reverse occurs, in the primarily infected children; 5) There was no correlation between total antibodies anti-PV levels and evidence of splenomegaly;6) Cytophilic antibodies (lgG1 > IgG3) predominated over noncytophilic antibodies (lgG2) in the study sample.