DETERMINATION OF THE SIZE OF HIV USING ADENOVIRUS TYPE-2 AS AN INTERNAL LENGTH MARKER

The size of a virion is a key criterion to its proper classification a nd may have implications in many practical aspects. Size determination s by thin section electron microscopy often result in length aberratio ns of more than 10% because of a number of preparative and instrumenta l inaccuracies, e.g. specimen shrinkage or swelling and unreliable cal ibration. Using adenovirus type 2 as an isometric size marker for inte rnal calibration, we have determined the diameters of mature and immat ure, HIV-1 to be 110 to 128 and 132 to 146 nm, respectively. The marke r had been used either as a purified particle suspension added to the HIV producing culture, or adenovirus had been propagated together with HIV by infecting HIV producing cells. Using well characterized isomet ric markers, e.g. an icosahedral virus, in thin section electron micro scopy appears to be a suitable technique for viral size determinations .