nuclear antigens were extracted from calf thymus with phosphate-buffered saline the 60-80 % ammonium sulfate fraction ( asf ) of thymus extract contained ss-b- , the 30-60 % asf sm- and u1-rnp- , and the chromatographically purified 30-60 % asf only sm antigen .
C0069115
nuclear antigens
C0003320
antigen