RESUMO
Oral administration of protein antigens, such as ovalbumin, may result in induction of either tolerance or immunization. To avoid oral tolerance, there are new strategies to protect the antigens from degradation within the gastrointestinal tract and to allow them to reach inductive immunological sites. One such strategy is the usage of liposomes. Different parameters may influence the stability of liposomes in the gastrointestinal tract. Herein, we studied the immunological consequences of oral administration of liposome-encapsulated ovalbumin in different strains of mice using different liposomes. Our data demonstrated that ovalbumin liposomes improved the induction of oral immunization and the degree of improvement depended on the liposome type and on the strain of mice used. The mechanism responsible for this differential effect of liposomes depended on the site of antigen release and absorption. Therefore, some liposomes might be suitable as adjuvants for oral immunization, others for oral tolerance induction.
Assuntos
Tolerância Imunológica , Lipossomos/química , Ovalbumina/administração & dosagem , Vacinação/métodos , Adjuvantes Imunológicos/administração & dosagem , Administração Oral , Animais , Citocinas/biossíntese , Ensaio de Imunoadsorção Enzimática , Imunidade nas Mucosas/imunologia , Imunoglobulina A/imunologia , Imunoglobulina E/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Lipossomos/administração & dosagem , Camundongos , Ovalbumina/imunologiaRESUMO
In this paper, an immune-inspired model, named innate and adaptive artificial immune system (IA-AIS) is proposed and applied to the problem of identification of unsolicited bulk e-mail messages (SPAM). It integrates entities analogous to macrophages, B and T lymphocytes, modeling both the innate and the adaptive immune systems. An implementation of the algorithm was capable of identifying more than 99% of legitimate or SPAM messages in particular parameter configurations. It was compared to an optimized version of the naive Bayes classifier, which has been attained extremely high correct classification rates. It has been concluded that IA-AIS has a greater ability to identify SPAM messages, although the identification of legitimate messages is not as high as that of the implemented naive Bayes classifier.
Assuntos
Algoritmos , Biomimética/métodos , Correio Eletrônico/classificação , Sistema Imunitário/imunologia , Modelos Biológicos , Antígenos/imunologia , Linfócitos B/imunologiaRESUMO
Oral tolerance is a phenomenon that may occur in animals exposed to soluble antigens for the first time by the oral route. In the present study, we show that oral tolerance against ovalbumin (Ova) can be obtained after intragastric administration of the antigen in the presence of free residues of palmitate. On the other hand, oral tolerance induction is blocked when the residues of palmitate are covalently bound to the antigen (Ova-palmitate conjugates). We have also noticed that oral administration of Ova-palmitate conjugates can boost and/or prime experimental animals for Ova-specific cellular and humoral systemic immune responses. Oral treatment with the conjugates also induces the production of local secretory immunoglobulin A (IgA) as measured in intestinal washes. Furthermore, Ova-palmitate given orally can inhibit oral tolerance induction by naïve Ova.
Assuntos
Tolerância Imunológica/imunologia , Imunoconjugados/farmacologia , Ovalbumina/imunologia , Palmitatos/imunologia , Administração Oral , Animais , Formação de Anticorpos/imunologia , Cruzamentos Genéticos , Feminino , Imunidade Celular/imunologia , Imunoconjugados/imunologia , Imunoglobulina A/análise , Imunoglobulina A/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Ovalbumina/administração & dosagem , Ovalbumina/farmacologia , Palmitatos/administração & dosagem , Palmitatos/farmacologiaRESUMO
The parotid lymph nodes of naive and previously infected Balb/c mice were studied after, respectively, infection and re-infection with cercariae of Schistosoma mansoni via the ears. Schistosomula were able to pass through the lymph node by following the lymph flow or by penetrating the veins of the medullary cords. The number of nodal mast cells was higher from day 2 to 6 of primary infection; and from day 5 to 11 of re-infection. The amount of degranulating mast cells was significantly higher at day 4 of infection and at day 1 of re-infection. Eosinophils characterized the nodal inflammatory processes observed after day 5 in both primarily-infected and re-infected mice. However, only in the latter the eosinophils were able to adhere to the larval surface. In primarily-infected mice, no intranodal larva presented signs of degeneration. In contrast, in re-infected animals, some degenerating larvae were found inside eosinophilic infiltrates. The eosinophils reached the nodal tissue by migrating through the high endothelial venules and their collecting veins.
Assuntos
Linfonodos/imunologia , Glândula Parótida/imunologia , Schistosoma mansoni/imunologia , Esquistossomose/imunologia , Animais , Contagem de Células , Eosinófilos/imunologia , Imunidade Celular , Linfonodos/parasitologia , Linfonodos/patologia , Masculino , Mastócitos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Glândula Parótida/parasitologia , Glândula Parótida/patologia , Esquistossomose/parasitologiaRESUMO
1. In order to study local tissue anaphylactic responses to infection with Schistosoma mansoni cercariae, mice of three different strains (C57BL/10J, Balb/cJ and CBA/J) were infected by subcutaneous injection of 15 to 20 cercariae. Eleven to 16 weeks later the animals were reinfected through one ear with 250 to 350 cercariae. 2. Throughout the infection period, the histamine content of the ears increased up to 150% of control values. Upon reinfection, the penetration of cercariae through the ear reduced its histamine content to near normal values. 3. Reinfection causes inflammation as judged by a 1.5 to 2.3-fold increase in the amounts of plasma leaking through the ear vessels as measured by leakage of Evans blue dye. 4. These results suggest that the local inflammatory reaction mediated by mast cells is important in the resistance of mice to reinfection with S. mansoni.
Assuntos
Anafilaxia/imunologia , Schistosoma mansoni/imunologia , Esquistossomose mansoni/imunologia , Animais , Histamina/metabolismo , Imunidade Celular , Masculino , Mastócitos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Schistosoma mansoni/fisiologia , Pele/metabolismoRESUMO
1. Evidence is presented for the participation of mast cells in the resistance of mice to infection by Schistosoma mansoni. 2. Intravenous injection of 1 micrograms/g body weight of the ionophore 48-80, a potent mast cell degranulator, significantly reduced (42-62%) the histamine content of the ear tissue of normal mice and either increased or decreased resistance to parasite penetration and infection depending on whether the injection of the ionophore was 5 min or 2 days before cercarial penetration. 3. When 48-80 was injected 5 min before the beginning of cercarial penetration, the number of parasites recovered from ear tissue 2 days later or from the portal system 30 days later was significantly reduced (39-71% and 27-40%, respectively) in relation to untreated controls. This resistance caused by 48-80 was blocked when mice were simultaneously treated with cyproheptadine, an antagonist of vasoactive amines. 4. In contrast, when 48-80 was administered 2 days before the beginning of cercarial penetration, the number of parasites retrieved from ear tissue 2 days later or from the portal system 30 days later was 32-64% and 28-30% larger, respectively, in relation to untreated controls. 5. These findings indicate that the local inflammatory reaction mediated by mast cells is important in the resistance of mice to infection with S. mansoni.