RANTES, A monocyte and T lymphocyte chemotactic cytokine releases histamine from human basophils
Chemotaxis of different populations of cells and release of proinflammatory mediators in response to antigenic stimulation are important processes in allergic diseases. These lead to the late phase response, a hallmark of chronic allergic diseases. Recombinant RANTES, a member of the "intercrine/chemokine" family of cytokines, has been previously shown to be chemotactic for monocytes and T cells of memory/helper phenotype. In this manuscript, we show that it is capable of inducing histamine release from human basophils at concentrations as low as 10(-10) M and compare its activity with that of monocyte chemotactic and activating factor/monocyte chemoattractant protein-1 (MCAF/MCP-1), another intercrine/chemokine. RANTES (10(-7) M) caused histamine release from the leukocytes of 26 of 33 donors tested (mean 21.8 +/- 3.1%). In the same group of donors, MCAF/MCP-1, goat anti-human IgE (anti-IgE; 1 microgram/ml), and FMLP (10(-5) M) released 41.1 +/- 2.9%, 40.5 +/- 4.6%, and 44 +/- 3.1% histamine, respectively. The percent histamine release by RANTES in atopic vs nonatopics was 30.3 +/- 6.7 and 16.5 +/- 2.4, respectively (p less than 0.05), and histamine release by RANTES correlated significantly with histamine release by MCAF (r = 0.69; p less than 0.001) but not with histamine release by anti-IgE (r = 0.29; p greater than 0.05). Histamine release by RANTES and MCAF/MCP-1 was extremely rapid, reaching a maximum within 1 min. RANTES was also shown to activate highly purified basophils (80% pure), and its activity was inhibited by a polyclonal anti-RANTES antibody. At a suboptimal concentration (6 x 10(-9) M), RANTES did not prime basophils to enhance histamine release by secretagogues such as anti-IgE, C5a, or FMLP. On the other hand, preincubation of basophils with RANTES or MCAF/MCP-1 desensitized basophils to either factor but not to anti-IgE, C5a, or FMLP. Preincubation of basophils with pertussis toxin markedly diminished the basophil response to either RANTES or MCAF/MCP-1. These results suggest that RANTES and MCAF/MCP-1: 1) are potent activators of basophils; 2) may function via the same, or a closely related, receptor system in basophils; and 3) may represent a link between activation of monocytes, lymphocytes, and basophils in inflammatory disorders such as the late phase allergic reaction.