Molecular and cellular properties of human polymorphonuclear leukocyte receptors for leukotriene B4.

The distinctive characteristics of human polymorphonuclear (PMN) leukocyte receptors for leukotriene B/sub 4/ (LTB/sub 4/) have been elucidated by studies of binding of (/sup 3/H)LTB/sub 4/, the structure of protein constituents of the receptors isolated from plasma membranes, and the effects of antireceptor antibodies. A high-affinity class of 4400 receptors with a K/sub D/ of 0.4 nM mediates chemotaxis and increased adherence of PMN leukocytes, whereas a low-affinity class of 270,000 receptors with a K/sub D/ of 61 nM mediates the release of lysosomal enzymes and increases in oxidative metabolism. The low-affinity receptors are composed of a 60,000-dalton protein-binding unit. The high-affinity receptors are composed of the same binding unit in association with a 40,000-dalton guanine nucleotide-binding protein. That antireceptor antibodies as well as LTB/sub 4/ distinguish the two classes of receptors with different functional consequences suggests the possibility of unique approaches to the regulation of leukocyte function at the receptor level.