Studies on the intergenerical precipitinogen beta with special reference to its presence in mycobacterial ribosomes.

Abstract

Preparations consisting of crude ribosomes and 50S, 30S and 16S ribosomal subunits from strains of the species <i>BCG, Mycobacterium fortuitum, M. phlei </i>and <i>M. smegmatis </i>were analysed by means of immunodiffusion technique for the presence of a precipitinogen designated <i>β. </i>For comparative purposes, mycobacterial cell wall and protoplasm preparations were also analysed regarding <i>β. </i>This precipitinogen has previously been found in culture filtrates and expressed materials from most mycobacterial and several nocardia and rhodochrous strains tested. In addition, antibodies against <i>β </i>have been demonstrated in sera from patients with leprosy. In the present study it was shown that <i>β </i>exists in all of the ribosomal preparations from all four strains tested. It was also demonstrated that <i>β </i>probably is the principle precipitinogen of 16S core particles from mycobacteria. Ribosomal <i>β </i>did not disappear when heated for 15 min at 100 °C. Ribosomal 16S preparations from all the four test strains reacted with sera against culture filtrate or expressed preparations from strains of heterologous mycobacterial species and nocardia and rhodochrous species. The precipitinogen formed could, in several cases, be identified as <i>β. </i>It was therefore postulated that the <i>β </i>precipitinogen which is shared by mycobacterial, nocardia and rhodochrous strains constitutes a part of the ribosomal structure. Furthermore, antibodies against mycobacterial 16S preparations were found in sera from patients with leprosy indicating that ribosomal material from the <i>M. leprae </i>bacilli has stimulated the production of these antibodies.