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What Is Australia Antigen?

Yvonne E. Cossart, MB, BSc, MRC Path, DCP
Am J Dis Child. 1972;123(4):321-322. doi:10.1001/archpedi.1972.02110100053021.
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When negatively stained preparations of Australia antigen are examined in the electron microscope, three types of particle can be distinguished. The most plentiful are approximately spherical and about 160 to 220 angstroms in diameter. Substructure is difficult to find, but the appearance suggests that the particles are built up of a number of identical subunits.1

Long particles are also seen in most instances. These have about the same diameter as the small spherical particles but vary greatly in length from bacilliform or ovoid structures to long filamentous ones. Some have expanded ends, some are bent at sharp angles, and many exhibit cross-striations which have a periodicity of 35 A.2

The third particle type is the double-shelled or "doughnut" form which is about 450 A in diameter and consists of a central core which is sometimes penetrated by the stain, surrounded by a shell which also seems to be


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