Lyophilized combination pools of enterovirus equine antisera: new LBM pools prepared from reserves of antisera stored frozen for two decades.

This paper describes the preparation and test procedures for a second batch of lyophilized LBM combination antiserum pools, A through H, used for identifying 42 enteroviruses. Each pool is selectively composed of 10 or 11 of 42 individual enterovirus equine sera so that it contains 500 antibody units of each serum component per 0.1 ml. The new pools have been constituted from equine monovalent antisera that were prepared during the period 1962-67 and then evaluated and standardized in a series of collaborative international studies. An essential aspect of preparing the new pools was ensuring that the individual sera had retained high antibody titres through the long period of storage. At the time of retesting, the original stocks of these monovalent sera had been stored frozen at -20 degrees C for periods ranging from 16 to 20 years.