55,000-dalton, retrovirus-associated, cell membrane glycoprotein: purification and quantitative measurements of expression in viruses, cells, and tissues

A microradioiodination method for detection of nanogram amounts of proteins resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis

A procedure is described for the rapid analysis of nanogram quantities of protein resolved by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE). Proteins are first radioiodinated by the chloramine T method, acid precipitated after addition of a visible marker protein and collected on a nitrocellulose filter. The region of the filter containing protein is excised and the proteins are then extracted from the filter into electrophoresis sample buffer.

Association of human T-cell leukaemia/lymphoma virus with the Tac antigen marker for the human T-cell growth factor receptor

Certain adult T-cell lymphoproliferative disorders are associated with human T-cell leukaemia virus (HTLV), a unique human type C retrovirus. (The strains of HTLV used in these studies belong to the subgroup HTLV-I.) HTLV is not an endogenous agent in man, but rather is an acquired virus with T-cell tropism. Neoplastic cells from patients infected with HTLV generally express receptors for T-cell growth factor (TCGF) (interleukin-2), and do not require prior activation with antigens or lectins to undergo TCGF-induced proliferation. Furthermore, neoplastic T-cell lines originating from such patients may constitutively produce TCGF, TCGF receptors and HTLV virions. HTLV is transmissible from cell to cell, and the infection of human T cells in vitro is associated with the expression of TCGF receptors, which can be identified by the monoclonal antibody termed anti-Tac. In our experience to date, T-cell populations that produce HTLV without exception also express epitopes found on TCGF receptors. Recognition of an association between HTLV virions and the Tac antigen would have clinical and theoretical implications. We now present evidence that during the replication or release of HTLV, the virion becomes preferentially associated with the Tac antigen.