|KEHRLI, JR, MARCUS|
Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 9/28/1998
Publication Date: N/A
Technical Abstract: The in situ expression of intercellular adhesion molecule-1 (ICAM-1) mRNA in the lung tissues of Holstein calves with bovine leukocyte adhesion deficiency syndrome (BLAD) was compared to age-matched non BLAD Holstein calves by in situ hybridization. Twenty-four Holstein calves (both BLAD and non BLAD) were randomly assigned to one of two experimental groups and inoculated intrabronchially with Pasteurella haemolytica or pyrogen-free saline. Lung tissues were collected and fixed in 10% neutral formalin at 2 or 4 hours post-inoculation. The expression and distribution of ICAM-1 mRNA on the different cell types of the lung tissue was detected by in situ hybridization with a 307 base pair bovine ICAM-1 riboprobe. In lungs of both non BLAD and BLAD saline-inoculated calves, ICAM-1 expression was present on epithelial cells but occurred in <30% of bronchi, bronchioles, and alveoli. ICAM-1 expression in vascular endothelial cells was present in <30% of pulmonary arteries and veins. The expression of ICAM-1 was significantly greater (>60%) on bronchiolar epithelial cells and pulmonary endothelial cells of arteries and veins in both BLAD and non BLAD calves inoculated with P. haemolytica. Bronchiolar epithelium had the highest degree of expression, while bronchial epithelium the lowest. Alveolar macrophages and bovine neutrophils in infected lungs also expressed ICAM-1. The increased expression of ICAM-1 during acute P. haemolytica pneumonia in calves suggests that ICAM-1 is upregulated and may play a role for leukocyte infiltration. The extent of ICAM-1 expression in calves with BLAD was similar to non BLAD calves which suggests that leukocyte adhesion deficiency does not enhance ICAM-1 expression.