FABF8:STX2 RECOMBINANT MONOCLONAL ANTIBODIES AVOID THE DELETERIOUS EFFECTS OF SHIGA TOXIN TYPE 2 ON HUMAN MICROVASCULAR ENDOTHELIAL CELLS

GOMEZ FERNANDO; LUZ, DANIELA; PIAZZA, ROXANE M. F.; PRESTA, AGOSTINA; IBARRA CRISTINA; SACERDOTI FLAVIA; AMARAL MARÍA M

Modalidad Virtual

Congreso; Reunión de Sociedades de Biociencias 2021; 2021

SAIC. SAI. AAFE. NANOMED

Hemolytic Uremic Syndrome (HUS) associated with Shiga‐toxigenicEscherichia coli (STEC) infections is the principal cause of acuterenal injury in pediatric age groups in Argentina. Neither a licensedvaccine nor effective therapy for HUS is available for humans. Previously,we demonstrated the in vitro cytotoxic effects of Shiga toxintype 2 (Stx2) on human glomerular endothelial cells (HGEC). Recently,recombinant antibodies against Stx2, produced in bacteria,were developed, and characterized. In this work, we studied the abilityof anti-Stx2 FabF8:Stx2 antibody to neutralize the Stx2 activity onprimary cultures of HGEC. Cells were plated in 96-well plates andgrown to confluence. Then, cells were treated in growth-arrestedconditions for 72 h with different pre-incubations (1 h at 37ºC) orco-incubations of FabF8 with Stx2. Antibodies were used from 10μg/mL to 0.001 μg/mL and Stx2 at the dilution required to kill 50%of cells (0.5 ng/mL). Finally, cell viability was assessed by neutralred uptake. In addition, cells were seeded on gelatine coated glasscoverslips and then treated, as it was previously mentioned, with1 μg/mL FabF8 and 0.5 ng/mL Stx2, during 72 h. Percentage ofnecrotic and apoptotic cells were established by fluorescence microscopyafter staining with acridine orange/ethidium bromide. Underboth conditions evaluated, FabF8:Stx2 significantly neutralized,in a dose-dependent manner, the cytotoxic effects caused by 0.5ng/mL Stx2 in HGEC (p