Interleukin 1 release by human alveolar macrophages and blood monocytes

These studies utilized a sensitive and specific radioimmunoassay for interleukin 1 beta (IL-1 beta) to compare release of IL-1 by human alveolar macrophages and blood monocytes. The studies demonstrate that alveolar macrophages release amounts of antigenic IL-1 beta that are similar to that of blood monocytes. The amounts of IL-1 released were similar for both cell types at early (4 h) and late (24 h) time points and with differing amounts of stimuli [endotoxin; lipopolysaccharide (LPS)]. In addition, alveolar macrophages actually produced more total IL-1 (intracellular IL-1 plus released IL-1) than did blood monocytes. Alveolar macrophages that were stimulated with LPS released significantly more prostaglandin E2 (PGE2, an inhibitor of IL-1) than did blood monocytes. These studies demonstrate that human alveolar macrophages are not defective in their capacity to release IL-1.