DEVELOPMENT OF ENZYMO-IMMUNOASSAYS (EIA) FOR MACROPHAGE-COLONY-STIMULATING FACTOR (M-CSF) AND LEUKEMIA INHIBITORY FACTOR (LIF) BY USING THESAME CAPTURE AND SIGNAL GENERATING POLYCLONAL ANTIBODY

Specific high titre polyclonal antibodies rapidly obtained by intralym phnode immunization of rabbits with recombinant M-CSF and LIF (< 60 mu g/animal) have been used to develop specific, accurate and sensitive EIAs. The same batch of purified anti-M-CSF or anti-LIF Igs has been u sed for the coating of 96-well plates (capture antibody) and for the q uantitative detection of the bound cytokine molecules (soluble biotiny lated Igs), The sensitivity (M-CSF: 10 IU/ml, LIF: 20 pg/ml), accuracy (intra-assay-CV: 8.2 to 12.8% for M-CSF; 0 to 19.9% for LIF) and repr oducibility (inter-assay-CV: 7.9 to 13.6% for M-CSF; 4.9 to 17.5% for LIF) are equivalent to those for previously published RIAs or EIAs, Th ese assays are highly specific since 11 other cytokines (Epo: 3 IU/ml; G-CSF: 100 IU/ml; CNTF, OSM, SCF, IL-1 beta, IL-2, IL-3, IL-6, IL-11, IL-13: 5 ng/ml) tested in both EIAs were not detectable, Finally, the M-CSF and LIF concentrations measured in various biological fluids we re found to be similar to those measured by us and others with differe nt assays, In conclusion, the methodology used for M-CSF and LIF EIAs presented in this work represents a valuable approach for most cytokin es, particularly when they are still available in reduced amounts. (C) 1996 Academic Press Limited