Measurement of human and murine interleukin 2 and interleukin 4

This unit describes protocols employing cell lines or bioassays that can be used for the quantitation of murine total T cell growth factor (TCGF) activity, interleukin 2 (IL-2), and interleukin 4 (IL-4), and of human IL-2 and IL-4. The ability to distinguish between different growth factors is crucial to understanding the regulation of the immune response. The Basic Protocol describes the use of the CTLL-2 line to detect murine IL-2 and IL-4 in supernatants. One alternate protocol describes the detection of IL-2 in samples of human serum or supernatants using CTLL-2 cells, while other alternate procedures describe the detection and quantitation of murine IL-4 using a mutagenized subline of CTLL-2, CT.4S, and the detection of human IL-4 using a derivative of the CT.4S mouse cell line, CT.h4S. Support protocols are provided for the quantitation of CTLL-2, CT4.S, or CT.h4S proliferation using a standard [3H]thymidine incorporation method or by using the 3-(4,5-dimenthylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay (Support Protocol 1). Support protocols also describe the calculation of cytokine units from samples based on DNA synthesis data and procedures for the maintenance of the CTLL-2, CT.4S, and CT.h4S cell lines.