[Characteristics of preparations of typhoid antigens obtained by ultrafiltration]

The properties of the preparations of the total typhoid antigens isolated by various methods, purified and concentrated by ultrafiltrations, were studied, and the technique of the preservation of their high solubility on drying (the neutralization and removal of disperse components prior to drying) was developed. Preparations obtained by ultracentrifugation were characterized by lower ash content and, when compared with alcohol tryptic preparations, had better antigenic properties, inducing the synthesis of not only O- and Vi-, but also H-antibodies in high titers.