Mosaic vaccine for HIV

Mosaic vaccines are synthetic peptides, generated by an algorithm that cover all combinations of known sequences of HIV antigen. The most challenging problem to solve in order to produce an effective vaccine against HIV is the high rate of variability in viral genome. Indeed, viruses tend to mutate rapidly to prevent the host’s immune defences; variations between individuals and different regions have been also reported.
Thus, HIV vaccines must initiate an immune response that recognizes a wide range of epitopes from several strains and from mutated variants of particular epitopes. Two studies have been published about mosaic vaccines. The first one has evaluated the effect of three mosaic vaccines, namely against gag, pol and env antigens on cellular culture. Some evidences of improved cellular response have been described. These results have been confirmed by the second study where only mosaic gag antigen has been kept in account. Up to date mosaic vaccines have been tested only in animal models and some concerns about the goodness of the model have been risen. It has been suggested a further confirmation by using SIV as infecting agent that can better contaminate animal than HIV. Nevertheless, these studies seem promising and give a realistic hope to obtain HIV vaccine.