Production of antibodies to platelet activating factor

Elucidation of the pathophysiological role of platelet activating factor (PAF) in health and disease is currently hampered by the lack of a sensitive, reproducible and easily applied assay for this potent phospholipid. This study describes the preparation of PAF in an immunogenic form, the production of antibodies to PAF and their use in the development of a preliminary RIA for PAF. Antibodies formed in response to a synthetic PAF analog coupled to a protein carrier were detected with two types of solid phases: PAF non-covalently adsorbed onto NC and the PAF analog covalently linked to PA. The latter was also used as a support for the isolation of anti-PAF antibodies by affinity chromatography. Quantitative hapten inhibition studies showed that the antibody combining sites were complementary to PAF and that cross-reactivity to lyso-PAF and some related phospholipids was negligible. Using these antibodies, [3H]PAF and Protein A-Sepharose as a means of separating bound and free tracer, the feasibility of developing a quantitative RIA for PAF was demonstrated.