RESUMO
The IgE immune response was studied in female athymic, nude (Lewis rnu/rnu) and euthymic (Lewis +/+) rats infected with the nematode Nippostrongylus brasiliensis. During the course of the infection, serum IgE levels were followed using an enzyme-linked immunosorbent assay technique (ELISA), while the surface expression and occupancy of IgE receptors on peritoneal mast cells were quantified using flow cytometry after immunolabelling with anti-IgE. The results show that the up-regulation of IgE receptors, which takes place on the mast cells of both athymic and normal rats during the early phase of the immune response, is more pronounced and longer-lasting in normal rats than in athymic ones, thereby suggesting that T cells are necessary for a full response to the parasite infection. The increased IgE occupancy observed on the mast cells during the early phase of the parasite immune response was not reflected in the serum IgE levels, which remained low during the entire infection period in athymic rats. In euthymic rats, on the other hand, there was a pronounced increase in serum IgE, as well as an increase in IgE occupancy on the mast cells, all reaching a peak level after 2 weeks of infection. However, there was no significant correlation between the serum IgE concentration and IgE occupancy or the density of IgE receptors on the mast cells of the individual euthymic rats. This indicates that the quantification of IgE occupancy on the mast cells may be a better way of detecting low-level IgE responses than the measurement of serum IgE. These findings, which were obtained in female Lewis rats, when compared with our previous findings in male rats of the same strain, suggest that sex differences may exist in terms of the intensity and duration of the IgE immune response to the parasite infection.
Assuntos
Imunoglobulina E/imunologia , Mastócitos/imunologia , Nippostrongylus , Infecções por Strongylida/imunologia , Linfócitos T/imunologia , Animais , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Imunoglobulina E/sangue , Ratos , Ratos Nus , Receptores de IgE/metabolismo , Infecções por Strongylida/sangueAssuntos
Humanos , Recém-Nascido , Lactente , Formação de Anticorpos , Aleitamento Materno , Leite Humano , Nutrição do LactenteRESUMO
Paired samples of stool and serum of 32 members of the Shipibo tribe resident in the rain forest of the Peruvian lowlands were tested for worm egg count and serum lipid parameters, respectively. 90% of the stool samples tested were found to contain eggs or larvae of several worm species, most commonly 3 or 4 different species. Serum lipid levels were found to be relatively low, most probably due to a low proportion of dietary fat ranging from 16-31%. Statistical analysis showed a significant inverse correlation between worm egg excretion and HDL levels which was true for hookworm, strongyloides and trichuris, but not for ascaris. The mechanisms underlying the observed association between intestinal worm load and HDL reduction are not completely understood and may include reduced HDL synthesis in the gut wall due to inflammatory and/or toxic irritation.