ovalbumin and Toxocariasis

The protective effect of infectious agents against allergic reactions has been thoroughly investigated. Current studies have demonstrated the ability of some helminths to modulate the immune response of infected hosts. The objective of the present study was to investigate the relationship between Toxocara canis infection and the development of an allergic response in mice immunised with ovalbumin (OVA). We determined the total and differential blood and bronchoalveolar lavage fluid cells using BALB/c mice as a model. To this end, the levels of interleukin (IL)-4, IL-5 and IL-10 and anti-OVA-IgE were measured using an ELISA. The inflammatory process in the lungs was observed using histology slides stained with haematoxylin and eosin. The results showed an increase in the total number of leukocytes and eosinophils in the blood of infected and immunised animals at 18 days after infection. We observed a slight lymphocytic inflammatory infiltrate in the portal space in all infected mice. Anti-OVA-IgE levels were detected in smaller proportions in the plasma of immunised and infected mice compared with mice that were only infected. Therefore, we concluded that T. canis potentiates inflammation in the lungs in response to OVA, although anti-OVA-IgE levels suggest a potential reduction of the inflammatory process through this mechanism.

Topics: Animals; Antibodies; Biopsy; Bronchoalveolar Lavage Fluid; Enzyme-Linked Immunosorbent Assay; Eosinophils; Hypersensitivity; Immunoglobulin E; Inflammation; Interleukin-10; Interleukin-4; Interleukin-5; Leukocyte Count; Lung; Mice, Inbred BALB C; Ovalbumin; Toxocara canis; Toxocariasis

Epidemiological studies performed in developing as well as in western countries suggest that infection with Toxocara canis contributes to the development of atopic diseases.. To investigate the association between infection with this helminth and allergy, we examined the effect of T. canis infection on experimental allergic airway inflammation.. BALB/c mice were infected by oral administration with 500 embryonated T. canis eggs followed by ovalbumin (OVA) sensitization and challenge to induce allergic airway inflammation.. Infection with T. canis in combination with OVA treatment leads to exacerbation of pulmonary inflammation, eosinophilia, airway hyperresponsiveness, OVA specific and total IgE. Relative quantification of cytokine expression in the lungs of these mice showed increased expression of IL-4 compared with mice that were only T. canis infected or OVA treated. Increased expression of IL-5 and IL-10 was measured in the lungs of T. canis-infected or OVA-treated mice compared with controls; however, combining infection and OVA treatment did not significantly change the expression of these cytokines.. A previous infection with T. canis leads to exacerbation of experimental allergic airway inflammation. These results have important consequences for findings on the helminths-allergy association. Several factors, including parasite species, infection of definitive vs. accidental host, parasite load and timing of infection, may influence whether an infection with helminths protects one from or enhances allergic manifestations.

Topics: Animals; Bronchial Hyperreactivity; Bronchoalveolar Lavage; Cytokines; Disease Models, Animal; Female; Immunoglobulin E; Inflammation; Lung; Lung Diseases, Parasitic; Mice; Mice, Inbred BALB C; Ovalbumin; Reverse Transcriptase Polymerase Chain Reaction; Risk Factors; RNA, Messenger; Time Factors; Toxocara canis; Toxocariasis

Histopathology of the lung and total IgE in serum were compared in toxocariasis and allergic asthma murine models using BALB/c and C57BL/6 mice. Infection with Toxocara canis resulted in both strains of mice in marked histological changes and increased levels of total serum IgE. The ovalbumin (OVA) sensitization/challenge treatment for the induction of allergic asthma resulted in similar histological changes in BALB/c and, to a less extent, in C57BL/6 mice. Serum IgE levels of OVA-treated C57BL/6 mice were low. Histological changes observed included perivascular infiltration with eosinophils and mononuclear cells, peribronchiolitis, alveolitis and mucus production. Although these changes in addition to increased IgE production did occur in T. canis-infected C57BL/6 mice they were more pronounced in BALB/c mice. Thus, BALB/c mice appear to be the most appropriate strain of mice to perform studies on the possible connection between infection with T. canis and allergic asthma.

Topics: Animals; Asthma; Bronchial Provocation Tests; Eosinophils; Immunoglobulin E; Leukocytes, Mononuclear; Lung; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Models, Animal; Ovalbumin; Toxocara canis; Toxocariasis