IDEHU   05542
INSTITUTO DE ESTUDIOS DE LA INMUNIDAD HUMORAL PROF. RICARDO A. MARGNI
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
DIFFERENTIAL ACTIVITY AT THE INNATE IMMUNE RESPONSE OF TWO SAGS OF THE EGC OPERON
Autor/es:
NOLI TRUANT SOFÍA; ANTONOGLOU MARÍA BELÉN; FERNÁNDEZ LYNCH MARÍA JULIETA; FERNÁNDEZ MARISA MARIEL; SARRATEA MARÍA BELÉN; MALCHIODI EMILIO LUIS
Lugar:
Mar del Plata
Reunión:
Congreso; LXIV Reunión Anual de la Sociedad Argentina de Inmunología; 2016
Institución organizadora:
SAIC-SAI
Resumen:
Bacterial superantigens (SAgs) are enterotoxins that bind to the MHC class II molecules and the TCR, activating as high as 20% of T cells and promoting a cytokine storm which enhances endotoxic shock and produces temporally immunosuppression, hindering the immune response against bacterial infection. The egc operon, reported in autochthonous strains of S. aureus, includes natural variants of the SAgs genes seg, sei, sem, sen and seo. Here, we characterized the complementary activity of SEO and SEM in respect to innate response.To test their superantigen activity and virulence, SAgs were exposed to different cell cultures to evaluate proliferation and viability by using [methyl-3H]thymidine and MTT. In order to characterize macrophage activation, arginine activity was measured in cell lysates, and nitrite was determined in culture medium. To evaluate the activity at MCH-II level DR1 interaction with SEO was evaluated by Western Blot and their affinity interaction was measured by surface plasmon resonance.SAgs have shown:1- Ability to activate peripheral blood mononuclear cells at distinctive concentrations;2-Differential cytotoxic effect upon monocytes and different stages of mature macrophages 3-Exposure of macrophages to SEM, but no SEO, increased nitrite in culture medium of differentiated THP-1 cells, only SEO on the other hand, increased nitrite in culture medium of RAW cells 4.-Reduction on arginase activity in cell lysates. 4-Specific interaction between SEO-DR1SEO and SEM exhibit superantigen activity at the innate immunity level, showing a complementary cytotoxic activity, favoring a very soft M1 response that is triggered at different stages for each SAg. The singularity of this differential response may be the key for the successful of the bacteria?s survival.