ovalbumin and Tracheal-Diseases

Total and differential white blood cells (WBC), and cytokines, levels in serum were examined in guinea pigs exposed to inhaled lead acetate. Different groups of guinea pigs including: control (group C), sensitized group (group S), and exposed animals to aerosol of three lead concentrations during sensitization (n = 6 for each group) were studied. Total and differential WBC counts of lung lavage, serum cytokine (IFNγ and IL-4), levels and tracheal responsiveness to methacholine and ovalbumin were measured. All measured values were significantly increased except for IFNγ/IL-4 ratio which was significantly decreased in nonexposed sensitized and those exposed to all lead concentrations compared to control group (p < 0.05 to p < 0.001). Most measured values in animals exposed to higher lead concentration were also significantly higher than group S except for tracheal responsiveness to methacholine and lymphocyte count. Lead concentration significantly increased in lung tissues of animals exposed to all three lead concentrations (p < 0.001 for all cases). These results showed that lead exposure during sensitization can induce greater increase in tracheal responsiveness, total WBC, eosinophil, neutrophil, and basophil counts as well as serum level of IL-4. It can also cause a decrease in lymphocyte count, IFNγ level, and IFNγ/IL-4 ratio especially in its high concentration. Therefore inhaled lead exposure may cause increased severity of asthma during development of the disease.

Topics: Animals; Dose-Response Relationship, Drug; Guinea Pigs; Inhalation Exposure; Interferon-gamma; Interleukin-4; Lead; Leukocyte Count; Leukocytes; Lung; Methacholine Chloride; Organometallic Compounds; Ovalbumin; Pneumonia; Tracheal Diseases

A recent increase in allergic disorders has coincided with a decrease in infections, including tuberculosis. Although an inverse association between tuberculin responses and atopic disorders was reported, it was not known how T-helper (Th)1-biased immune responses to Mycobacterium tuberculosis influenced Th2-dominant responses to allergens. We examined whether M. tuberculosis could modulate ovalbumin (OVA)-induced eosinophilic inflammation in the murine trachea in a manner that transcended the barrier of antigen specificity. We found that CD4(+) T cells primed with OVA in complete Freund's adjuvant (CFA) inhibited OVA-induced tracheal eosinophilia through interferon (IFN)-gamma secretion. Immunization with an irrelevant antigen in CFA or with OVA in incomplete Freund's adjuvant failed to induce suppressor cells. In vitro experiments confirmed that both M. tuberculosis and OVA (as opposed to either one alone) were necessary to evoke polarized development toward a Th1-like phenotype through interleukin-12 secretion. These results indicate that exposure to an allergen along with M. tuberculosis switches development of allergen-specific T cells toward a Th1 phenotype, which, in turn, downregulates allergic manifestations in an antigen-specific manner. The possible implications of these results are discussed in the context of the causal relationship between a decrease in tuberculosis and an increase in allergic disorders.

Topics: Animals; Asthma; CD4-Positive T-Lymphocytes; Dose-Response Relationship, Drug; Eosinophilia; Hypersensitivity; Interferon-gamma; Interleukin-12; Interleukin-4; Mice; Mice, Inbred BALB C; Mice, Transgenic; Models, Biological; Mycobacterium tuberculosis; Ovalbumin; Phenotype; Th1 Cells; Th2 Cells; Tracheal Diseases

A rat model of immediate pulmonary hypersensitivity was used to investigate the permeability changes in the tracheal epithelium produced by aerosol challenge with antigen. The rats were sensitised by the intraperitoneal injection of antigen (dinitrophenyl (DNP19) ovalbumin). Sensitised and control animals were then challenged for 60 minutes with an aerosol of the same antigen, which also contained the electron dense pore marker lanthanum. Histological examination and x ray probe microanalysis showed a greater intercellular concentration of lanthanum in the tracheal epithelium in sensitised than in control animals. The results show that in sensitised rats increased intercellular penetrance of antigen can occur after antigen challenge.

Topics: Animals; Dinitrophenols; Disease Models, Animal; Epithelium; Hypersensitivity, Immediate; Male; Microscopy, Electron; Ovalbumin; Permeability; Rats; Rats, Inbred Strains; Trachea; Tracheal Diseases