ARS | Publication request: DIFFERENTIAL DEGRANULATION RESPONSE OF CHICKEN HETEROPHILS TO GRAM-POSITIVEAND GRAM-NEGATIVE BACTERIA IS NOT MEDIATED BY TOLL-LIKE RECEPTOR 4

Submitted to: American Society of Microbiologists Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: March 21, 2002
Publication Date: N/A

Technical Abstract: The innate immune response protects against extracellular pathogens and utilizes pattern recognition receptors (PRRs), which in turn recognize molecularly conserved components known as pathogen-associated molecular patterns (PAMPs). Heterophils are essential mediators of the innate immune response in neonatal chickens; however, the induction of functional activity by diverse pathogens is not fully understood. The ability of either formalin killed gram-negative bacteria (Salmonella enteritidis [FKSE] and lipopolysacharide [LPS]) or gram-positive bacteria (Staphylococcus aureus [FKSA] and lipoteichoic acid [LTA]) to promote degranulation in heterophils isolated from neonatal chicks were evaluated. For these experiments, immune IgG opsonized SE, which is known to stimulate degranulation through the Fc receptor, was used as a positive control. The response generated by FKSE, LPS, FKSA, and LTA was 84%, 84%, 94%, and 92%, respectively, lower than the opsonized SE control. However, despite the marked decrease in degranulation when compared to the positive control, the FKSE and LPS did promote a significant increase in degranulation when compared to the non-stimulated heterophil control (p = 0.02 and 0.009, respectively). However, neither the gram-positive bacteria nor LTA stimulated a degranulation response. Therefore, there is a distinct functional difference in the ability of gram-positive and gram- negative bacteria to stimulate the bactericidal activity of degranulation in heterophils isolated from day old chickens.