A method useful for regulating cytokine production by a hematopoietic cell
by regulating an MEKK/JNKK-contingent signal transduction pathway in such
a cell is disclosed. Methods of identifying compounds capable of
specifically regulating an MEKK/JNKK-contingent signal transduction
pathway in hematopoietic cells, a kit for identifying cytokine regulators,
methods to treat diseases involving cytokine production, and cells useful
in such methods are also set forth.