Staphylococcus aureus causes chronic mastitis in the bovine and is a major health concern in humans. The goal of this study is to elucidate the mechanism by which S. aureus infects DC and evades immune responses and antibiotic treatments. Inhibiting DC apoptosis would provide S. aureus with a replicative niche, an escape from treatments, and a reprieve from the immune system. DC were treated with either live S. aureus, live Streptococcus agalactiae , γ-irradiated S. aureus, or UV. Apoptosis was measured via annexin V/FITC and PI staining by flow cytometry at 48 hours post-infection. Treatment with either S. agalactiae or UV induced a significant increase in apoptotic DC (annexin V+/PI-) percentages as compared to untreated DC. However, there was no significant increase in percentage of apoptotic DC following treatment with live or irradiated S. aureus as compared to no treatment. We concluded that S. aureus does not induce, but may inhibit, DC apoptosis. These data supply knowledge about the ability of S. aureus to manipulate the host immune system and will provide information from which to design efficacious vaccine strategies.
- Copyright © 2013 by The American Association of Immunologists, Inc.