Bovine Alveolar Macrophages: Phenotypic and Functional Properties of Subpopulations Obtained by Percoll Density Gradient Centrifugation

Publisher Website
Google Scholar
Abstract
Bronchoalveolar cells retrieved from conventionally raised, healthy calves were separated into four fractions on a discontinuous Percoll density gradient. The alveolar macrophage (AM) subpopulations and nonseparated AM were assayed for such phenotypic markers as la-antigen, ectoenzymes, and immune receptors, as well as for functional activity in antibody-dependent cellular cytotoxicity (ADCC) against virus-infected cells, superoxide anion generation, and their influence on lectin-induced lymphocyte proliferation. The low-density fraction was composed of large cells with low la-antigen expression, low ADCC activity, and high ecto-enzyme and C3b-receptor activity. In contrast the high-density fraction contained mainly small, monocytelike cells, with high la expression and low-level expression of most other markers and functions. Two fractions of intermediary density overlapped in most of the characteristics, but could be distinguished on the basis of ADCC activity, interleukin-1 generation, and the level of leucine amino peptidase activity.