Purification and inactivation of the factor X activator of Russell's viper venom with monoclonal antibodies.

Two monoclonal antibodies, MP1 and MP2, specific for factor X activator (RVV-X) present in Russell's viper venom (RVV) have been produced. The antigenic components of the venom which bound to the antibodies on affinity columns showed identical mobilities, molecular weight 85,000, on sodium dodecyl sulphate/polyacrylamide gels. Antigen purified by one antibody bound to the other. The RVV components eluted from MP1 and MP2 affinity columns were active in promoting blood coagulation and hydrolysed purified factor X. Neutralization tests in vitro showed that MP2 but not MP1 inhibited the coagulant activity of RVV-X. Competitive binding assays showed that MP1 and MP2 recognized different antigenic sites on RVV-X. The possible clinical applications of these antibodies are discussed.