Homograft Antigens: Isolation of Fractions of Normal Cells which retain Activity after Freeze-drying

Abstract

IN previous reports¹, we have described the isolation from splenic and lymph node cells of homograft antigens which required immediate bioassay, because they lost antigenic activity rapidly on standing and were almost totally inactivated by simple freezing or by freeze-drying. These early preparations, however, afforded materials which enabled us to develop an assay procedure and to examine some of the properties of antigenic fractions. In the course of these examinations, newer methods of antigen preparation were devised, based on the isolation of subcellular fractions from sucrose solutions. Brent et al.², Manson et al.³ and Davies⁴ have recently reported the preparation of transplant antigens from sources and by methods that diifer from those described below.