Background and purpose: Methicillin resistant Staphylococcus aureus (MRSA) is a community-associated pathogen that is so common in hospitals. Antibiotic resistance and poor clinical outcome provide great reasons for using immunization strategies based on antibodies. The aim of this study was to investigate passive immunity using recombinant anti-MRSA ScaF antibody in a mouse model.

Materials and methods: In this study, the recombinant protein, ScaF was purified through denaturation method. This protein combined with Freund’s adjuvant was injected into a rabbit to produce antibody. Then, the antibody produced against ScaF was injected to mice infected by S. aureus by two regimens of pre- and after infection treatment. Afterwards, the mortality rate in mice was compared between the control treatment group (vancomycin therapy) and negative control group (non-immune rabbit serum).

Results: Out of 10 mice in two groups of pre- and after infection treatment that received antibody against ScaF antigen 20% and 10% were protected, respectively, that did not show a significant difference compared with non-immune rabbit serum group (negative control).  

Conclusion: Passive immunization by antibody cannot play a considerable role in the control of infections caused by S. aureus. Therefore, other mechanisms of immune system for the protection against this bacterium including stimulating of cytokine-dependent cell-mediated immunity may be useful in prevention of infections caused by S. aureus.