Reacción a "Further progress towards an effective HIV vaccine through a sequential approach"

Given the difficulty of generating neutralising antibodies against HIV, the authors guide the immune system to generate a specific type of neutralising antibodies with different immunogens: first simpler (so that they can be better recognised) and then more complicated and closer to the original HIV envelope protein. The studies are technically excellent and analyse in depth the evolution of the sequentially generated antibodies. 

This strategy is well known and has been used before. The HIV envelope protein has different regions that are recognised by neutralising antibodies. For one specific region (the CD4 binding site), this strategy has already been used and has even been studied in humans. Now we have a second region (the base of the V3 loop) that can also be used in a similar way. Combining the two strategies could generate a greater quantity and diversity of these neutralising antibodies (which would make a potential vaccine more effective). 

The main limitation is that both studies have been conducted in animals and cannot be quantitatively translated to humans.  

Studies also highlight the difficulty of generating an HIV vaccine. Sequential vaccination may be an excellent strategy, but it may require an excessive number of immunogens, which would make it difficult to turn this strategy into a product that reaches the population most in need. Much work remains to be done.