VIROLOGY 26, (1965)

Fine Structure of Filaments in Dog Kidney

Cell Cultures Infected with Measles Virus

Concerning the fine structure of the in- clusion bodies observable in measles-infected cells, there are reports by Kalhnan el al. (I), Baker et al. (z?), and Tawara et al. (3). Kallman et al. reported mainly on the fine structure of the intranuclear inclusion body observed in HeLa cells, Baker et al. on the crystallites in the nuclei of human amnion cells, and Tawara et al. on the fine structure of filaments in the int’ranuclear inclusion bodies observed in dog kidney cells infected with measles virus.

In this paper the filaments found in dog kidney cells infected with measles virus are described with greater precision.

The cells used were primary monolayer cultures of dog kidney cells infected with the Edmonston strain of measles virus (4), at lOPlO TCID,,, per milliliter. The methods of preparing the specimens for electron microscopy and of identifying in- clusion bodies have been reported previously. The observations were made with a Hitachi electron microscope HU-11.

Four days after the inoculation of measles virus, inclusion bodies were recognizable in the nuclei (Fig. 1). In these bodies, numerous filaments are seen intermingled in an ir- regular fashion, and in some areas numerous filaments are aggregated in a strand forma- tion. In this picture, the section was cut parallel to the long axis of the filaments, the longest of which measure over 450 nq. From serial sections it becomes clear that these filaments are aggregated in an orderly manner and, keeping this regular array, they make detours in every direction. In cross- section particularly, they look like granules in a crystalline arrangement.

In Fig. 2 the filaments are shown at a greater magnification: some appear singly as long strings in longitudinal section, while

DISCUSSION ANI) PRELIWNART REPORTS

in cross-section they appear as scattered, hollow dark spots. Filaments present a tubu- lar structure, the inside diameter measur- ing about lo-15 n1l.l and the outside diameter about 15-20 rnp.

These filaments form a bigger aggregate with time, and ultimately the inclusion body is completely filled up with them. Such fibrous filaments can be seen also in the irnracytoplasmic inclusion bodies. These filaments may be involved from the onset of virus formation.

REFERENCES

1. K~LLMAN, F., ADAMS, J. M., WILLIAMS, R. C., and IMAGAW~, D. T., J. Biophys. Cytol. 6, 379-382 (1959).

1. BAKER, R. F., GORDON, I., and RAPP, F., ,Vature 185, 79&791 (1960).

3. TAW.~RA, J. T., GOOD?UN, J. R., IM~GAW-A, D. T., and ADAMS, J. M., Virology 14, 110- 416 (1961).

4. ENDERS, J. F., and PEEBLES, T. C., Proc. Sot. Exptl. Biol. Med. 105, 547-551 (1954).

JUT.~RO T.i\\7.k~.~ Department of Microbiology Okayama University Medical School Okayama, Japan

Accepted November 3, 1964

Development of Interferon in Rabbit Dermis

after Infection with Herpes Simplex Virus

A previous report (1) has indicated that lesion formation in the rabbit following intradermal injection with herpes simplex virus is the direct result of virus multiplica- tion. The present study was designed to determine (a) whether interferon is present at the site of the lesion, (b) at what time and in what concentration it appears, and (c) its relationship to viral multiplication.

Procedure for infection of rabbits, as well as methods for preparation and titration of lesion homogenates for infectious virus, have been previously described (1).

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