BOVINE PULMONARY ALVEOLAR MACROPHAGES - ANTEMORTEM RECOVERY AND INVITRO EVALUATION OF BACTERIAL PHAGOCYTOSIS AND KILLING

  • 1 January 1984
    • journal article
    • research article
    • Vol. 45  (9) , 1842-1847
Abstract
A system was developed to recover pulmonary alveolar macrophages (PAM) from living cattle and to evaluate the function of these cells by measuring bacterial phagocytosis and killing. For the collection of PAM, single-tube and telescoped double-tube pulmonary lavage devices were compared. The total recovery, using these systems, was 70 .+-. 10.7% of infused fluid, yielding .apprx. 87% PAM. The total number of cells per collection was .apprx. 5 times higher with the single-tube device (6.87 .+-. 0.78 .times. 107 cell/ml) than with the telescoped double-tube device (1.3 .+-. 0.1 .times. 107 cells/ml). Phagocytosis and intracellular killing of Staphylococcus epidermidis and Staphylococcus aureus by PAM in media suspension and by plastic-adherent PAM were evaluated. In addition, different bacteria-to-macrophage ratios were assessed, as well as the intracellular killing of S. epidermidis at periodic intervals. Over a 3-h period, similar numbers of both bacteria were phagocytized, but intracellular killing of S. epidermidis was more efficient than intracellular killing of S. aureus. It also was found that suspended PAM and adherent PAM phagocytized similar numbers of bacteria; when the bacteria-to-cell ratio was 10:1, the numbers of phagocytized bacteria and intracellular killing were higher than when the ratio was 1:10; and killing of S. epidermidis by adherent PAM was directly proportional to incubation time. The time that PAM are in culture affects the phagocytosis and killing of intracellular bacteria, as shown by increased phagocytosis and by intracellular killing of S. epidermidis by PAM in suspension for 48 h or plastic adherent for 60 h after collection.