A comparative study of the indirect haemagglutination (IHA), immunofluorescence (IFAT)

Heme oxygenase-1 (HO-1) is an enzyme that catabolizes free heme, which induces an intense inflammatory response. The expression of HO-1 is induced by different stimuli, triggering an anti-inflammatory response during biological stress. It was previously verified that HO-1 is able to induce indoleamine 2,3-dioxygenase (IDO), an enzyme that is induced by IFN-γ in Toxoplasma gondii infection. To verify the role of HO-1 during in vivo T. gondii infection, BALB/c and C57BL/6 mice were infected with the ME49 strain and treated with zinc protoporphyrin IX (ZnPPIX) or hemin, which inhibit or induce HO-1 activity, respectively. The results show that T. gondii infection induced high levels of HO-1 expression in the lung of BALB/c and C57BL6 mice. The animals treated with ZnPPIX presented higher parasitism in the lungs of both lineages of mice, whereas hemin treatment decreased the parasite replication in this organ and in the small intestine of infected C57BL/6 mice. Furthermore, C57BL/6 mice infected with T. gondii and treated with hemin showed higher levels of IDO expression in the lungs and small intestine than uninfected mice. In conclusion, our data suggest that HO-1 activity is involved in the control of T. gondii in the lungs of both mouse lineages, whereas the hemin, a HO-1 inducer, seems to be involved in the control of parasitism in the small intestine of C57BL/6 mice.

BackgroundToxoplasma gondii is an intracellular parasite that causes relevant clinical disease in humans and animals. Several studies have been performed in order to understand the interactions between proteins of the parasite and host cells. SAG2A is a 22 kDa protein that is mainly found in the surface of tachyzoites. In the present work, our aim was to correlate the predicted three-dimensional structure of this protein with the immune system of infected hosts.MethodsTo accomplish our goals, we performed in silico analysis of the amino acid sequence of SAG2A, correlating the predictions with in vitro stimulation of antigen presenting cells and serological assays.ResultsStructure modeling predicts that SAG2A protein possesses an unfolded C-terminal end, which varies its conformation within distinct strain types of T. gondii. This structure within the protein shelters a known B-cell immunodominant epitope, which presents low identity with its closest phyllogenetically related protein, an orthologue predicted in Neospora caninum. In agreement with the in silico observations, sera of known T. gondii infected mice and goats recognized recombinant SAG2A, whereas no serological cross-reactivity was observed with samples from N. caninum animals. Additionally, the C-terminal end of the protein was able to down-modulate pro-inflammatory responses of activated macrophages and dendritic cells.ConclusionsAltogether, we demonstrate herein that recombinant SAG2A protein from T. gondii is immunologically relevant in the host-parasite interface and may be targeted in therapeutic and diagnostic procedures designed against the infection.

BackgroundTherapy for allergic rhinitis aims to control symptoms and improve the quality of life. The treatment of allergic rhinitis includes allergen avoidance, environmental controls, pharmacologic treatment, and specific immunotherapy.ObjectivesThe aim of this study is to evaluate the clinical changes and the levels of interferon-γ (IFN-γ) and interleukin-5 (IL-5) in nasal lavage fluid from children with allergic rhinitis after different types of pharmacologic treatment (mometasone, montelukast, or desloratadine).MethodsTwenty-four children aged from six to 12 years with moderate persistent allergic rhinitis were randomized into three groups receiving monotherapy treatment over four weeks: nasal corticosteroid (mometasone), leukotriene modifier (montelukast), or antihistamine (desloratadine). The perception of symptom improvement during the medication use was evaluated at the end of the treatment. Samples of nasal lavage fluid were collected before and after treatment for measuring IFN-γ and IL-5 cytokines by ELISA.ResultsAll parents perceived an improvement in symptoms. Significant enhancement was seen in the mometasone group compared to those with montelukast (P = 0.01) and desloratadine (P = 0.02). No significant differences were found among the three groups in the levels of IL-5 and IFN-γ in nasal fluid at baseline or after treatment. Only the group treated with mometasone showed a slight but significant reduction in IL-5 levels after the treatment period as compared with levels before the treatment (P = 0.0469).ConclusionThe group treated with mometasone showed better improvement of clinical symptoms and a slight reduction in IL-5 levels in the nasal fluid. This may indirectly reflect the relative immunomodulatory effects of the drugs tested.