Submitted to: Society for Leukocyte Biology Meetings Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 9, 2001
Publication Date: N/A
Technical Abstract: The innate immune response protects against extracellular pathogens and utilizes pattern recognition receptors (PPRs), which in turn recognize molecularly conserved components known as pathogen-associated molecular patterns (PAMPs). Heterophils are essential in establishing an innate immune response in neonatal chickens; however, the functional activity and the mechanism(s) of action involved are not fully understood. The ability of either Salmonella enteritidis (SE) and lipopolysacharide (LPS) or Staphylococcus aureus (SA) and lipoteichoic acid (LTA) to promote degranulation and oxidative burst in heterophils isolated from neonatal chicks was evaluated. Immune IgG opsonized SE was used as a positive control, which stimulates both activities through the Fc receptor. Treatment of heterophils with SE, LPS, SA, and LTA decreased degranulation activity by 76%, 78%, 90%, and 90%, respectively from the opsonized SE control. In addition, oxidative burst was evaluated using a quantitative luminol-dependent chemiluminescence assay. SE, LPS, SA, and LTA all stimulated a significant oxidative burst in heterophils that was dramatically reduced by the addition of polyclonal antibody to Toll-like receptors 2 and 4. Therefore, Toll-like receptors mediate oxidative burst but not degranulation, indicating at least two distinct pathways are involved in the function of heterophil killing.