A process is disclosed for the production of an antifusogenic peptide by producing a fusion peptide of a length of about 14 to 70 amino acids in a prokaryotic host cell, comprising the steps, under such conditions that inclusion bodies of said fusion peptide are formed, of: (a) expressing in said host cell a nucleic acid encoding said fusion peptide consisting of a first peptide which is an antifusogenic peptide of a length of about 10 to 50 amino acids and a second peptide of a length of about 4 to 30 amino acids, said first peptide being N-terminally linked to said second peptide; (b) cultivating said host cell to produce said inclusion bodies; and (c) recovering said antifusogenic peptide from said inclusion bodies, wherein said recovered antifusogenic peptide consists of said fusion peptide or a peptide comprising the antifusogenic peptide of about 10 to 50 amino acids and which is a fragment cleaved from said fusion peptide. Inclusion bodies of the peptides are disclosed. Also disclosed is a nucleic acid encoding the fusion peptide consisting of a first peptide which is an antifusogenic peptide selected from the group of SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, and said sequences further consisting of glycine at the C terminal end, N-terminally linked to the second peptide.