IDEHU   05542
INSTITUTO DE ESTUDIOS DE LA INMUNIDAD HUMORAL PROF. RICARDO A. MARGNI
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Staphylococcus aureus egc and group ii superantigens induce glucocorticoid resistance in human peripheral blood mononuclear cells (PBMCs
Autor/es:
FERNÁNDEZ LYNCH MJ; NOLI TRUANT S; SARRATEA MB; ANTONOGLOU MB; DE MARZI MC ; MALCHIODI EM; FERNÁNDEZ MM
Lugar:
bUENOS aIRES
Reunión:
Congreso; II Congreso Argentino ?Francés de Inmunología, LXIII Reunión Anual de la SAI, IV Congreso LASID; 2015
Institución organizadora:
Sociedad Argentina de Inmunología
Resumen:
Background: Bacterial superantigens are exotoxins that bind in anon-classical way to T-cell Receptor and Mayor Histocompatibility Complex  triggering peptide-non-specific T cellproliferation and proinflammatory cytokine release. Immunosupressants, likeglucocorticoids, are used to revert inflammatory actions in Staphylococcus aureus toxin relateddiseases, however resistance to treatment has been reported for SEB and TSST-1[HAUK 2000]. Therefore, we aim to show whether the enterotoxin gene clustertoxins SEG, SEI, SEO and other group II toxins (SEC3, SSA and SER) can induce resistancein human peripherial blood mononuclear cells (PBMCs).Methods: Superantigens were recombinantly produced in E. coli BL21(SEG, SEC3, SEI, SER, SEO, SSA and SEG hotspot mutants: D172A, G20A, F204A, N24A and N24D) and were purified byNi-NTA. PBMCs were enriched from heparinized blood using Ficoll-Hypaquegradient, cultured for 48/72 hours for proliferation assessment with3H-thymidine under different stimuli (Superantigens 1 or 10ug/ml, dexamethasonefrom 10-9-10-5 M and Ly294002 at 1 or 10 uM).Results: PBMCs treated with 1ug/ml of SEC3 and SEI and 10ug/ml ofSEG, SER, SEO and SSA show significant proliferation at high doses ofdexamethasone (10 uM) comparing with RPMI treated cells (2way ANOVA,p<0.001). TCR binding site directed mutants of SEG show decreased resistance(10-7 M). PI3K ihibitor, Ly294002 (1uM) reduces resistance (2wayANOVA, p<0.01), suggesting as well the role of TCR signalling throughactivating NFKB upstream factors in glucocorticoid resistance.Conclusions: Understanding the underlying mechanisms ofglucocorticoid resistance in Staphylococcus toxin related diseases can helpimprove treatment outcome in pacients.