|Lowry, Virginia - TEXAS A&M UNIVERSITY|
Submitted to: Society for Leukocyte Biology Meetings Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 24, 1996
Publication Date: N/A
Technical Abstract: Injection of Samonella enteritidis-immune lymphokines (SE-ILK) into day- old chicks potentiates the avian inflammatory response which is characterized by: (a) increased numbers of circulating granulocytes (heterophils), (b) activation of biological activity of the heterophils, and (c) directed influx of the activated heterophils to the site of bacterial invasion. The directed migration of granulocytes to an inflamed site is dependent on the extravasation of the cells from the blood and the establishment of a chemotactic gradient at the local site. Both events are dependent on the expression of granulocyte membrane receptors. We have previously found increased expression of the CD11b/CD18 adhesion molecule on the heterophils 4 h after SE-ILK administration. Additionally, we found the production of the chemokine, IL-8, at or near the site of bacterial invasion which attract the heterophils. The objective of the present study was to examine the kinetics of SE-ILK-induced membrane expression of the CD11b/CD18 molecule and the putative IL-8 receptor. Maximal expression of CD11b/CD18 (75% positive fluorescence using FACScan) occurred within an hour after injection of SE-ILK. The expression of the adhesion molecule remained greater than 60% throughout the 4 h study. IL-8 receptor expression was induced on a subpopulation of heterophils which was maximal (67% positive) by 2 h post-SE-ILK injection. However, the number of heterophils positive for the IL-8 receptor decreased rapidly over the next 2 hours as the IL-8 receptor-positive cells left the blood and migrated to the site of bacterial infection. These results demonstrate that SE-ILK induces a rapid differential expression of the CD11b/CD18 adhesion molecule and IL-8 receptors on the membrane of the avian heterophil.