say isolated from a natural source or synthetic for example by performing site directed metagenesis on the dna it is thus apparent that polynucleotides of the invention can be either naturally occurring or recombinant that is to say prepared using recombinant dna techniques an allelic variant will be a variant that is naturally occurring within an individual organism nucleotide sequences are homologous if they are related by divergence from a common ancestor consequently a species homologue of the polynucleotide will be the equivalent polynucleotide which occurs naturally in another species within any one species a homologue may exist as numerous allelic variants and these will be considered homologues of the polynucleotide allelic variants and species homologues can be obtained by following standard techniques known to those skilled in the art u201c adjuvant u201d means a composition comprised of one or more substances that enhances the immunogenicity and efficacy of a vaccine composition non limiting examples of suitable adjuvants include squalane and squalene or other oils of animal origin block copolymers detergents such as tween u00ae 80 quil u00ae a mineral oils such as drakeol or marcol vegetable oils such as peanut oil corynebacterium derived adjuvants such as corynebacterium parvum propionibacterium derived adjuvants such as propionibacterium acne mycobacterium bovis bacillus calmetic and guerinn or bcg interleukins such as interleukin 2 and interleukin 12 monokines such as interleukin 1 tumour necrosis factor interferons such as gamma interferon combinations such as saponin aluminium hydroxide or quil a aluminium hydroxide liposomes iscom adjuvant mycobacterial cell wall extract synthetic glycopeptides such as muramyl dipeptides or other derivatives avridine lipid a dextran sulfate deae dextran or dhae dextran with aluminium phosphate carboxypolymethylene such as carbopol u2032 ema acrylic copolymer emulsions such as neocryl a640 e g u s pat no 5 047.