PURIFICATION STUDIES ON THE INFECTIOUS CANINE HEPATITIS VIRUS : II. VIRAL PARTICLES AND THEIR CHARACTERISTICS REVEALED BY MODIFICATION OF THE PURIFICATION PROCEDURE

The picture of the infectious canine hepatitis virus particle derived from infections tissue culture fluid and cells has been clearly demonstrated by a modified purification procedure. It was able to observe the fine structure of the particle when the virus was stained with phosphotungstic acid or sodium phosphotungstate. Fixing the purified virus particles with 2% neutral formalin resulted in the revelation of a clearly hexagonal or pentagonal image. Purified ICH virus particles keep infectivity and complement fixing and hemagglutinating activities and can be disintegrated by treatment with ether with the liberation of smaller particle, soluble antigen and hemagglutinin. The ultraviolet absorption spectrum of final purified virus particles shows a maximum at 258 mμ and a minimum at 240 mμ

NUCLEAR BODIES IN CELLS OF VARIOUS LYMPHATIC ORGANS

The sizes and frequency of the nuclear bodies were observed in cells of the thymic cortex, thymic medulla, lymph node, spleen and patch of Peyer of mice. The nuclear bodies are most often found in small lymphocytes (32.3 to 37.1%) of the lymph node, spleen and patch of Peyer, but very rarely in small lymphocytes of the cortex (4.4%) and medulla (14.5%) of the thymus. The bodies are also often found in mesenchymal and epithelial reticular cells, but are variable in occurrence. From the frequency and size of the nuclear body in cells of lymphocytic series, it is suggested that in thymic cortex, about a half of the small lymphocytes contain a small nuclear body, and in the medulla all small lymphocytes contain a small or a large body, and in the other lymphatic organs all of small lymphocytes include two or more large, grouped, nuclear bodies. The outer filamentous coat of the nuclear bodies is closely related with nucleolus. No nuclear bodies were found in the large lymphocytes and mitotic cells. Thus the relationship between morphological changes of the nuclear body and differentiation of lymphocytes has been discussed in this paper

PECULIAR NUCLEAR INCLUSION, NUCLEOLOID BODY, IN LYMPHOCYTES

Peculiar nuclear inclusions, "nucleoloid bodies", were found in nuclei of several types of cells in mouse lymph nodes and in sheep hemal nodes. The nucleoloid bodies were morphologically independent of the nucleolus and the chromatin. They were spherical in shape, ranging from 200 to 900mμ in size, with outer and inner layers that could be differentiated. The outer layer consisted of numerous filaments arranged concentrically or spirally which encircle completely the inner layer. The filaments were helical coils, measuring 70〜80 Å in width. The diameter of the fibril coiled into the helix was approximately 20〜30 Å. The same helical fibrils were also found in the chromatins of nucleoplasm around the nucleoloid bodies. The inner layer was composed of a homogeneous substance of lower electron density and of a variable number of dense granules which were similar to ribosomes in appearance. At high magnification, however, the granules seemed to be twisted threads in which thinner fibrils were coiled. The threads were 200〜250 Å in width and the helical fibrils measured about 50 Å in diameter. The nucleoloid bodies were separated into two types. The first type was small, about 200〜300 mμ in size, and had no or a few dense granular elements in the inner layer. The second type was larger, over 400 mμ in size, whose inner layer had numerous granular elements. The nucleoloid bodies were most often observed in small lymphocytes, in particular the large bodies (second type) were almost limited to the small lymphocytes, though rarely in plasma cells as well. Even if nucleoloid bodies were found in cells other than small lymphocytes, it was rare finding and usually involved the small bodies (first type) only. The nucleoloid bodies seemed to derive from the true nucleoli and were observed in the chromosomes throughout mitosis. From the ultrastructure of the nucleoloid bodies, it was suggested that the bodies consist of a specialized nuclear protein unlike the chromosomes

FINE STRUCTURE OF POST-CAPILLARY VENULES IN MOUSE LYMPH NODES

The post-capillary venules of mouse lymph nodes were examined with optical and electron microscopes. The endothelial cells of these venules contain many mitochondria, well developed, rough-surfaced endoplasmic reticula, numerous free ribosomes, a prominent Golgi complex and three types of inclusions ; multivesicular bodies and dense inclusion bodies with and without a cuboid crystal. The prominent Golgi complex and the inclusion with a cuboid crystal are not present in the endothelial cells of other blood vessels in the lymph nodes of mice. The endothelium of the venules is surrounded by pericytes which correspond to ROUCET's cells which are usually only observed in arterial capillaries. All of cells migrating through the post-capillary venules are small lymphocytes and no other leucocytes are normally present. The small lymphocytes migrate by penetrating the junction between the endothelial cells but not by penetrating their cytoplasm. One degenearted cell (lymphocytes?) was observed between the endothelial cells of the venules