The ability of membrane ultra- and diafiltration and two chromatography media, Matrex(R) Cellufine(TM) Sulfate (Millipore) and Macro-Prep(R) ceramic hydroxyapatite (Bio-Rad), to adsorb, elute, and purify gene therapy vectors based on Moloney murine leukaemia virus (MoMuLV) carrying the 4070A amphotropic envelope protein was studied. Membrane ultra- and diafiltration provided virus concentration up to 160-fold with an average recovery of infectious viruses of 77 +/- 14%. In batch experiments, Macro-Prep(R) ceramic hydroxyapatite (type 2, particle size 40 mum) proved superior to Matrex(R) Cellufine(TM) Sulfate for MoMuLV vector particle adsorption. Furthermore, functional vector particles could be eluted using phosphate buffer pH 6.8 (highest titres from 300 mM phosphate) from the Macro-Prep(R) adsorbent, with higher specific titres (cfu/mg protein) than the starting material. Similar results were obtained when this ceramic hydroxyapatite was packed into a column and used in a liquid chromatography system. Recovery of transduction-competent virus was between 18 and 31% for column experiments and 32 and 46% for batch experiments.