Process for the production of biologically active HIV-1 tat protein

A process for the preparation of biologically active Tat suitable for human use, comprising the steps of:

• 1) culturing a host organism capable of expressing Tat when induced in a culture volume of at least 15 L, wherein the host organism is Escherichia coli, and wherein the Tat comprises the amino acid sequence set forth in SEQ ID NO:
• 3, or a mutant or variant thereof having biological activity comparable with biologically active Tat and having at least 70% sequence homology to said sequence;
• 2) culturing said host organism in a culture media that comprises a vegetable peptone and does not comprise components of animal origin;
• 3) inducing the expression of Tat during the logarithmic growth phase of the host organism;
• wherein the induction occurs at 0.6 OD of the host culture,
• 4) purifying Tat from the culture, wherein the yield is at least 15.8 mg of Tat for a culture volume of 15 L;
• and wherein the Tat produced is considered biologically active if at a concentration of 100 ng/ml it is taken up by at least 49% of a cell culture of monocyte-derived dendritic cells (MDDC).