The specific transfer factor(TF) is extracted from spleen of canine that have been immunized with attenuated canine distempervaccine(CDV).
本试验用犬瘟热弱毒苗免疫的犬，提取了特异性犬脾转移因子（TF） 。
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The rabies vaccine also needs to be given yearly, although due to the small size of ferrets, the rabies and Canine Distemper vaccines can't be given at the same time.