Occurrence of Glycogen in Inclusions of the Psittacosis-Lymphogranuloma Venereum-Trachoma Agents

Twenty-seven strains within the psittacosis-lymphogranuloma venereum trachoma group have been examined with reference to morphology of the intracellular inclusion in infected chick entodermal explants and McCoy cells, including the presence or absence of glycogen. On these bases 2 natural subgroups have been defined. All strains of trachoma and inclusion conjunctivitis agents, as well as 1 isolate each of lymphogranuloma venereum, mouse pneumonitis, and hamster pneumonitis, serve to establish an arbitrarily designated subgroup A, characterized by round or oval, somewhat rigid inclusions that contain glycogen. Seven other mammalian strains and 5 avian strains (subgroup B) exhibited irregular or diffuse inclusions with little or no rigidity and in no instance was glycogen seen in the inclusions. Glycogen appeared in the inclusions of subgroup A between 30 and 40 hours after infection of the cells and began to disappear at 72 hours and later. Particularly in the older inclusions the distribution of glycogen in the form of granules was evident. Penicillin in the culture medium interfered with glycogen production, as evidenced by the appearance of distorted and abnormal iodine and periodic acid-Schiff-stained material. The evidence is reviewed for glycogen being a product of the infectious agent rather than of the host cell.