Related Experiment Videos
Impaired function of bovine alveolar macrophages infected with parainfluenza-3 virus
Abstract:
Bovine alveolar macrophages (BAM) were harvested from nonsedated cattle, adhered to glass or plastic surfaces, and infected with parainfluenza-3 (PI-3) virus at a multiplicity of infection of 10. Control and PI-3 virus-infected BAM were compared at 24-hour intervals up to 168 hours for their ability to phagocytize antibody-coated sheep erythrocytes (EAC) and latex particles, to kill Staphylococcus epidermidis, and to alter intracellular acid phosphatase concentrations. The effect of antiviral serum on phagocytic functions of virus-infected cells was also evaluated. Compared with noninfected controls, alveolar macrophages infected with PI-3 virus were 15.3% less adherent to the glass or plastic surfaces at postinoculation hour (PIH) 72 and were 64.0% less adherent at PIH 168. Significant differences (P less than 0.05) between the numbers of control and infected BAM phagocytizing EAC were observed at PIH 24 through 72, with final values differing by approximately 50%. Similar changes were observed in the phagocytic efficiencies of individual cells. The PI-3 virus-infected BAM that were exposed to antiserum or to immunoglobulins against PI-3 virus had approximately a 2-fold greater inhibition in EAC phagocytosis than did infected BAM exposed to serum without PI-3 activity. Significant differences in latex particle phagocytosis were not observed between infected and control BAM. Compared with control BAM, the PI-3 virus-infected BAM contained significantly lower concentrations of acid phosphatase from PIH 48 through 96; at PIH 96, acid phosphatase concentrations were 4-fold less in infected than in control BAM.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Bovine alveolar macrophages infected with parainfluenza-3 virus show reduced adherence and phagocytosis of antibody-coated sheep erythrocytes. This viral infection also significantly decreases intracellular acid phosphatase concentrations in these immune cells.
Area of Science:
- Veterinary Immunology
- Cellular Immunology
- Virology
Background:
- Bovine alveolar macrophages (BAM) are crucial for respiratory defense in cattle.
- Parainfluenza-3 (PI-3) virus is a significant respiratory pathogen in cattle.
- Viral infections can impair macrophage function, impacting host immunity.
Purpose of the Study:
- To investigate the impact of PI-3 virus infection on the function of bovine alveolar macrophages.
- To assess changes in adherence, phagocytosis, bacterial killing, and enzyme activity post-infection.
Main Methods:
- BAM were isolated from cattle and infected with PI-3 virus.
- Macrophage adherence, phagocytosis of sheep erythrocytes (EAC) and latex particles, bacterial killing, and acid phosphatase levels were measured over 168 hours.
- The effect of antiviral serum on infected BAM phagocytosis was evaluated.
Main Results:
- PI-3 virus infection significantly reduced BAM adherence to surfaces.
- Phagocytosis of EAC by infected BAM was significantly reduced, while latex particle phagocytosis remained unaffected.
- Intracellular acid phosphatase concentrations were significantly lower in infected BAM.
- Antiviral serum exacerbated the inhibition of EAC phagocytosis in infected BAM.
Conclusions:
- PI-3 virus infection impairs key functions of bovine alveolar macrophages, including adherence and phagocytosis.
- The observed decrease in acid phosphatase suggests altered cellular metabolism or lysosomal function.
- These macrophage dysfunctions may contribute to the pathogenesis of PI-3 virus-associated respiratory disease in cattle.