Abstract: The invention relates to gene therapy of HIV infection by providing to a patient a nucleic acid for the expression of in vivo secretable peptides that prevent entry of the virus into the cell. The invention makes available nucleic acids and vectors containing the same that code for a fusion protein which contains two HIV entry inhibitory peptides which are connected by a cleavable linker, wherein the peptides are preferably derived from the second (C) heptad repeat of the gp41 protein of HIV.