Functional characterization of monoclonal antibodies to interferon-tau

Interferon tau (IFN tau) produces an array of biological effects, including antiluteolytic, antiviral, antiproliferative and immunomodulatory activiti es, without the consequent cytotoxicity associated with other type I IFNs, Four anti-IFN tau monoclonal antibodies (MAbs) have been characterized by d etermining regional epitopes and observation of their effects on IFN tau bi nding, antiviral and antiproliferative activity, Using an enzyme-linked imm unoadsorbent assay (ELISA) developed against six overlapping synthetic pept ides representing the entire linear sequence of IFN tau, three antibodies, HL-98, HL-100 and HL-127, were found to react with the carboxy terminal pep tide, while HL-129 bound the penultimate amino terminal peptide, Binding st udies indicated that MAbs directed against either region could effectively inhibit the binding of alkaline phosphatase labeled IFN tau to cells expres sing type I IFN receptors. While only two of the MAbs significantly reverse d IFN tau-induced growth inhibition, the antiviral activity of IFN tau was significantly inhibited by MAbs that bound the amino and carboxy termini, c onfirming the functional importance of these domains in the binding and sub sequent activity of IFN tau.