Submitted to: American Society for Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/20/2003
Publication Date: 4/20/2003
Citation: MEYERHOLZ, D.K., GRUBOR, B., GALLUP, J.M., LEHMKUHL, H.D., EVANS, R.B., ACKERMANN, M.R. ALTERATIONS OF SURFACTANT PROTEIN-A AND TUMOR NECROSIS FACTOR-ALPHA EXPRESSION DURING ACUTE BOVINE RESPIRATORY SYNCYTIAL VIRUS INFECTION. AMERICAN SOCIETY FOR MICROBIOLOGY ANNUAL MEETING. 2003. Abstract p. 675, #Z-004.
Technical Abstract: Background: Bovine respiratory syncytial virus (BRSV) is a significant respiratory pathogen of ruminants including cattle and sheep. Surfactant protein-A (SP-A) plays an important role in lung surfactant homeostasis and innate pulmonary immunity. Tumor necrosis factor-alpha (TNF-alpha) is a cytokine that is elevated during severe paramyxoviral disease. In vitro, SP-A expression can be inhibited by TNF-alpha expression. The purpose of this experiment was to assess SP-A and TNF-alpha expression during acute BRSV infection of neonatal lambs. Methods: In this study, twelve neonatal 3-5 day old lambs were infected with intratracheal and intranasal inoculum containing either BRSV media or sterile control media. Lambs were sacrificed at 3 and 6 days post infection. Lung tissues were snap frozen for real time RT-PCR or fixed in 10% buffered formalin for microscopic examination. Results: Lesions consistent with BRSV infection were present in virus-infected animals especially on day 6. During BRSV infection, SP-A mRNA expression decreased while TNF-alpha expression increased, and the logarithmic conversion of these values were inversely correlated (p<0.05, r**2=0.79). Furthermore, the alterations of SP-A and TNF-alpha corresponded to the clinical severity of BRSV infection. Conclusion: These results show that BRSV infection in neonatal lambs can alter SP-A and TNF-alpha expression, and they suggest that these alterations may in part contribute to the clinical expression of BRSV disease.