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Title: PRODUCTION OF ANIONIC PEPTIDE DURING PERACUTE BACTERIAL PNEUMONIA IN CATTLE

Author
item ACKERMANN, M - IOWA STATE UNIV.,AMES,IA.
item BROGDEN, KIM
item CAVERLY, J - IOWA STATE UNIV.,AMES,IA.
item FALES-WILLIAMS, A - IOWA STATE UNIV.,AMES,IA.
item DIXON, R - TEX.BIO.CORP.,HOUSTON,TX.

Submitted to: Gordon Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Anionic peptides are produced by epithelial cells of respiratory tract of humans and sheep. We have determined that anionic peptides are also produced by respiratory tract epithelia of cattle. In order to assess the production of anionic peptide during acute bacterial pneumonia, colostrum-deprived, neonatal calves (n = 4/group) were inoculated intrabronchially with either 1x 109 cfu of the Gram-negative pathogen Pasteurella haemolytica in 5 cc pyrogen-free saline (PFS) by fiberoptic bronchoscope or PFS alone (control). Bronchoalveolar lavage (BAL) fluid and lung tissue were collected at 2 and 6 hours post-inoculation. In order to assess the role of neutrophil infiltration on anionic peptide production during pneumonia, another group of P. haemolytica-inoculated calves were treated (25mg/kg) with the selectin inhibitor TBC1269 30 minutes prior to and 2 hours after bacterial inoculation; BAL fluid and tissues from these calves were collected at 6 hours post-inoculation. Anionic peptide was detected in BAL fluid of both PFS and P. haemolytica-inoculated calves; however, the antimicrobial activity anionic peptide in these calves was greatly reduced in comparison to BAL fluids from adult cattle. Levels of anionic peptide in BAL fluid were variable. Preliminary immunohistochemical studies indicate that the extent of anionic peptide production in lung tissue is reduced in areas of lung with the highest degree of neutrophil infiltration. This work demonstrates that anionic peptides are present in the lung of neonatal cattle during the early stages of bacterial pneumonia; however, the antimicrobial activity of anionic peptide in the neonatal calves was greatly reduced in comparison to adult cattle.