Monospecific antibodies to rabbit lung ribonucleases

Ribonucleases were isolated from normal rabbit lung by chromatographic techniques. Two active fractions were separated by elution from a sulfopropyl-Sephadex column with 0.2 and 1.0 M NaCl. These were further purified over 2000-fold from the original crude homogenate. Both RNase preparations showed more than one protein possessing RNase activity in polyacrylamide gel electrophoresis with either sodium dodecyl sulfate or low pH buffer systems. The purified fraction eluted at 0.2 M NaCl was injected into a goat. The resulting antiserum inhibited the RNase activity of both RNase preparations. Immunoelectrophoresis revealed three noncross-reacting precipitin arcs with the 0.2 M NaCl-eluted RNase and two noncross-reacting precipitin arcs with the 1.0 M NaCl-eluted RNase. Highly significant RNase activity was recovered from the beta arc in the former and the delta arc in the latter. By immunoabsorbant chromatography, the antiserum was separated into three monospecific fractions, anti-alpha, anti-beta, and anti-delta. Anti-beta and anti-delta inhibited, respectively, 60 and 33% of the 0.2 M NaCl-eluted RNase activity. Anti-delta inhibited 93% of the 1.0 M NaCl-eluted RNase activity. RNase activity in rabbit serum was not inhibited by any of the monospecific antibody fractions.