refeed and periodically harvest infected cultures several times before extensive cell destruction stops the formation of new virus.
ConclusionIn this necessarily brief report we have discussed certain aspects of the growth of measles virus in simian cell cultures for the preparation of inactivated vaccines. This is not to¡ imply that other sources cannot be used. On the contrary, recent evidence from our and other laboratories indicates that measles antigen can accumulate in avian, canine, or bovine cell cultures under the proper growth conditions. However, because of the vast experience acquired with simians through the use of poliomyelitis and adenovirus vaccines, because of the ex¬ tensive body of information of the cytology of monkey kidney tissue culture, and be¬ cause of its apparent freedom from allergenicity we believe the monkey offers a proved and reliable tissue source for killed measles vaccines.
SummaryThe various considerations which led to the use of simian kidney cell cultures for measles vaccine manufacture are briefly discussed. Virulent strains of measles are superior to attenuated strains for the pro¬ duction of antigen.