Characterization of a factor produced by human T cell clones exhibiting eosinophil-activating and burst-promoting activities.

It has long been suggested that eosinophil response observed in certain immunological reactions depends on the release of soluble products from sensitized lymphocytes when exposed to the challenging antigen. We were able to show that alloreactive T cell clones (ATLC) obtained from human rejected kidney produced, when stimulated with specific antigen (kidney donor-B lymphoblastoid cell line) and interleukin 2, a factor triggering the proliferation of a subline (DA-2) of the interleukin 3 sensitive DA-1 murine cell line. The biochemical features of this factor called HILDA (human interleukin DA) and the DA-2 nonresponsiveness to several human T cell lymphokines and cytokines lead us to the conclusion that this 41,000 m.w. glycoprotein could not be likened to already known T cell lymphokines. Highly purified HILDA turned out to be a potent chemoattractant and activator of, respectively, mouse and human eosinophils. It also displayed burst-promoting activity on human marrow.