Protein A-neutralizing monoclonal antibody protects neonatal mice against Staphylococcus aureus

Staphylococcus aureus is a cause of sepsis and meningitis in very-low-birth-weight (VLBW) infants. Clinical trials with S. aureus specific antibodies failed to protect VLBW neonates, which may be due to the immune evasive attributes of staphylococcal protein A (SPA). Here we show that mouse monoclonal antibody SpA(KKAA)-mAb 3F6, which neutralizes the immunoglobulin Fc gamma-binding and B cell receptor crosslinking attributes of SpA, protects neonatal mice against S. aureus sepsis and raises protective immunity against subsequent staphylococcal infection. We developed a humanized SpA(KKAA)-mAb that protects neonatal mice against S. aureus sepsis and may therefore be subjected to clinical testing in VLBW neonates. (C) 2014 Elsevier Ltd. All rights reserved.