Interferon alpha, beta. Includes also interferon omega and tau. Different from interferon gamma family. Type I interferons(alpha, beta) belong to the larger helical cytokine superfamily, which includes growth hormones, interleukins, several colony-stimulating factors and several other regulatory molecules. All function as regulators of cellular activty by interacting with cell-surface receptors and activating various signalling pathways. Interferons produce antiviral and antiproliferative responses in cells. Receptor specificity determines function of the various members of the family.