On the nature of anti-ribosome antibodies and some properties of their reaction with ribosomes

Comparative immunochemical study of ribosomal proteins from various mammalian cells by two-dimensional immunoelectrophoresis

Proteins isolated from ribosomal subunits of various mammalian cels were analysed comparatively by two different methods: a two-dimensional polyacrylamide gel electrophoresis system and a recently described two-dimensional immunoelectrophoresis technique. For this purpose, antisera were raised in rabbits against the total mixture of ribosomal proteins from murine cells. These sera were characterized by ring-test, double immunodiffusion and two-dimensional immunoelectrophoresis. They were shown to contain antibodies to a large number of ribosomal proteins. Immunoelectrophoretic analysis of 60S and 40S subunit proteins from rabbit, lamb, canine and human cells using anti-murine sera revealed a striking conservation of their antigenic properties. These results corroborated those obtained by two-dimensional polyacrylamide gel electrophoresis.

Immunochemical analysis of the structure of eukaryotic ribosomes: antigenic properties of rat liver ribosomes and ribosomal proteins and characterization of the antisera

Antibodies were prepared in rabbits and sheep to rat liver ribosomes, ribosomal subunits, and to mixtures of proteins from the particles. The antisera were characterized by quantitative immunoprecipitation, by passive hemagglutination, by immunodiffusion on Ouchterlony plates, and by immunoelectrophoresis. While all the antisera contained antibodies specific for ribosomal proteins, none had precipitating antibodies against ribosomal RNA. Rat liver ribosomal proteins were more immunogenic in sheep than rabbits, and the large ribosomal subunit and its proteins were more immunogenic than those of the 40S subparticle. Antisera specific for one or the other ribosomal subunit could be prepared; thus it is unlikely that there are antigenic determinants common to the proteins of the two subunits. When ribosomes, ribosomal subunits, or mixtures of proteins were used as antigens the sera contained antibodies directed against a large number of the ribosomal proteins.

Immunochemical assay for information in cytoplasmic polysomes

Only very small amounts of informatin could be detected in cytoplasmic polysomes with the aid of antiinformatin antibodies. This low amount of informatin cannot represent a structural component of polysomes or polysomal mRNP.

Immunogenic properties of eukaryotic ribosomal proteins

Pure rat, chicken and kidney bean ribosomal proteins are immunogenic in the rabbit as tested by the Ouchterlony double diffusion technique. On the other hand, we were unable to raise antibodies to rabbit ribosomal proteins in the guinea pig. Rabbit ribosomal proteins are not autoimmunogenic. Rabbit antisera to rat or chicken ribosomal proteins surprisingly give no cross-reaction with ribosomal proteins from other mammals (man, ewe, calf, guinea pig, mice) whereas antisera to kidney bean ribosomal proteins cross-react with lentil ribosomal proteins. It is suggested that the high conservation of ribosomal protein structure in mammals, as shown by two-dimensional electrophoresis, may account for the impossibility of raising antibodies to rabbit ribosomal proteins in the guinea pig and for the absence of any cross-reaction among mammals.