Dr. John Barton was awarded a PDA travel grant for the Jan-June 2015 cycle.
BIO: Dr. John Barton obtained his Ph.D. in Physics from Rutgers University in 2012 under the supervision of Prof. Joel Lebowitz. There he studied the statistical mechanics of simple one-dimensional lattice models and methods of graphical model inference. John is currently a postdoctoral fellow in the group of Prof. Arup Chakraborty, where he employs tools from statistical physics to study HIV and its evolution to help develop more rational methods for vaccine design.
RESEARCH OVERVIEW: The evolution of HIV is enormously influenced by its constant struggle with the host immune system. Mutations allow HIV to escape targeting by the immune system and thus replicate more quickly, but unless these mutations are made in coordinated ways they may render the virus defective. By analyzing viral sequence data, we found patterns of mutations used by HIV to evade the host immune response that are analogous to regular patterns of activity that appear in neural networks. These patterns can be interpreted as peaks on the viral fitness landscape. The number of patterns detected in immunogenic proteins – those that are frequent targets of the host immune response – dramatically outweighs the number of patterns detected in nonimmunogenic proteins, even though few differences appear between immunogenic and nonimmunogenic proteins at the level of sequence conservation. Our work provides a window into the dynamics of host-pathogen evolution, and the ways in which this coevolutionary process can be detected in sequence data. Our results may also be useful for the design of vaccines against HIV and other pathogens. Vaccines designed to force the virus away from common patterns of adaptation could push it into an evolutionary trap, where the only mutations available to evade the host immune response are those likely to significantly impair its ability to replicate.