ovalbumin and Mycobacterium-Infections

We expressed the CTL epitope of OVA (OVA(257-264)) in an acute (Listeria monocytogenes (LM)-OVA) and a chronic intracellular pathogen (Mycobacterium bovis (BCG)-OVA), to evaluate the kinetics of Ag presentation. LM-OVA proliferated rapidly in vivo, resulting in profound LM-OVA expansion within the first 24 h of infection, culminating in the generation of a potent CD8+ T cell response, which peaked on day 7 but underwent a rapid attrition subsequently. In contrast, BCG-OVA exhibited reduced growth in vivo, resulting in a delayed CD8+ T cell response that increased progressively with time. Relative to LM-OVA, BCG-OVA induced persistently increased numbers of apoptotic (annexin V+) CD8+ T cells. Ag presentation in vivo was evaluated by transferring Thy1.2+ carboxyfluorescein-labeled OT1 transgenic CD8+ T cells into infected Thy1.1+ congeneic recipient mice. LM-OVA induced rapid Ag presentation that was profound in magnitude, with most of the transferred cells getting activated within 4 days and resulting in a massive accumulation of activated donor CD8+ T cells. In contrast, Ag presentation induced by BCG-OVA was delayed, weaker in magnitude, which peaked around the second week of infection and declined to a low level subsequently. Increasing the dose of BCG-OVA while enhancing the magnitude of Ag presentation did not change the kinetics. Furthermore, a higher dose of BCG-OVA also accelerated the attrition of OVA(257-264)-specific CD8+ T cells. Relative to LM-OVA, the dendritic cells in BCG-OVA-infected mice were apoptotic for prolonged periods, suggesting that the rapid death of APCs may limit the magnitude of Ag presentation during chronic stages of mycobacterial infection.

Topics: Acute Disease; Animals; Antigen Presentation; Antigen-Presenting Cells; Apoptosis; CD8-Positive T-Lymphocytes; Cell Cycle; Cell Division; Cells, Cultured; Chronic Disease; Female; Listeria monocytogenes; Listeriosis; Lymphocyte Count; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Mycobacterium Infections; Mycobacterium tuberculosis; Ovalbumin

Our previous studies, as well as those of others, have demonstrated that local or systemic Mycobacterium bovis bacille Calmette-Guérin (BCG) infection can inhibit de novo allergen-induced asthma-like reactions, but the effect of this infection on established allergic responses is unknown. The aim of this study was therefore to examine the effect of mycobacterial infection on established allergy in a murine model of asthma-like reaction. Mice were sensitized with ovalbumin (OVA) in alum followed by infection with BCG and subsequent intranasal challenge with the same allergen. In some experiments, mice were sensitized with OVA followed by intranasal challenge with OVA and then given BCG infection with subsequent rechallenge with OVA. Mice without BCG infection but treated with OVA in the same manner, were used as a control. The mice were examined for immunoglobulin E (IgE) response and eosinophilic inflammation, mucus production, cytokine/chemokine patterns and adhesion molecule expression in the lung. The results showed that postallergen BCG infection suppressed the established airway eosinophilia and mucus overproduction, but not IgE responses. The inhibition of asthma-like reactions by BCG infection was correlated with a shift of allergen-driven cytokine production pattern and, more interestingly, with a dramatic decrease of vascular cell adhesion molecule-1 (VCAM-1) expression in the lung. These findings suggest that intracellular bacterial infection can inhibit established allergic responses via alteration of local cytokine production and the expression of adhesion molecules.

Topics: Animals; Antigens; Asthma; Cytokines; Endothelium, Vascular; Female; Immune Tolerance; Immunoglobulin E; Mice; Mice, Inbred C57BL; Mucus; Mycobacterium bovis; Mycobacterium Infections; Ovalbumin; Pulmonary Eosinophilia; Th2 Cells; Vascular Cell Adhesion Molecule-1

Cell walls of Mycobacterium smegmatis were able to produce much more severe arthritis in rats than the delipidated cells, whereas cell envelope and cell membrane fractions were unable to produce the disease. The lysozyme-solubilized product was able to produce mild disease with only 30% of incidence with an optimum dose, whereas the higher and the lower doses did not produce the disease. The rats immunized with cell envelope, cell membrane fraction and nonarthritogenic doses of lysozyme-solubilized product were protected against the subsequent homologous and heterologous challenge of delipidated cells. It was discussed that this preventative effect can be the result of antigenic competition between the arthritogenic and nonarthritogenic components of M. smegmatis. On the other hand, all the fractions separated here were able to serve as an immunoadjuvant in terms of inducing delayed hypersensitivity to ovalbumin in guinea pigs.

Topics: Animals; Arthritis, Rheumatoid; Cell Fractionation; Cell Wall; Female; Freund's Adjuvant; Guinea Pigs; Hypersensitivity, Delayed; Hypersensitivity, Immediate; Mycobacterium; Mycobacterium Infections; Ovalbumin; Rats; Rats, Inbred Lew; Tuberculin

Topics: Animals; Arthritis; Arthus Reaction; Bradykinin; Capillary Permeability; Carrageenan; Depression, Chemical; Dextrans; Disease Models, Animal; Dogs; Edema; Exudates and Transudates; Female; Formaldehyde; Granuloma; Guinea Pigs; Histamine; Hyaluronoglucosaminidase; Kaolin; Lymph; Male; Mice; Mycobacterium Infections; Ovalbumin; p-Methoxy-N-methylphenethylamine; Phytotherapy; Plants, Medicinal; Rabbits; Rats; Serotonin; Species Specificity; Swine