Speaker
Description
Advances in bacterial biofilm infection research have improved our understanding of antibiotic resistance and immune evasion, which can be explained by social behavior. Biofilms are structured cooperative communities wherein bacterial subpopulations have differing biological roles for biofilm maintenance. Social interactions among structured populations may also play a role in viral evolution and host adaptation. Hepatitis C virus, for example, has been hypothesized to exhibit antigenic cooperation wherein an altruistic variant diverts the immune system, resulting in the immune escape of persistent variants. This phenomenon suggests that, similar to bacteria, other chronic virus infections may also be better understood through this social lens. Interactions in such cooperative behavior require one or multiple genes maintained over time through compensatory mutations (i.e., co-evolution). HIV is one of the most rapidly evolving infectious viruses, capable of establishing chronic, systemic infection; immune evasion; and antiretroviral therapy resistance. Envelope (env) gene sequencing of the closely related S[imian]IV revealed putative compensatory mutations across infected anatomic compartments within the macaque model of HIV infection, indicating the similarities between difficult-to-treat HIV and biofilm infections may extend beyond site-level mutational selection to include social interactions. A Bayesian graphical modeling (BGM) approach was developed in order to measure the significance of identified co-evolving sites in interacting subpopulations among longitudinal samples from different tissues collected from 12 SIV-infected macaques. The BGM, implemented in GOSiP (Graphical Modeling Of Social Interactions using Phylogenies), was applied, revealing 14 total reconstructed co-evolutionary networks, five of which comprised sites common to eight macaques. SIV co-evolution across anatomic compartments is consistent with genomic interactions across subpopulations, the maintenance of which may be vital for overall population fitness. Additionally, common sites across animals allude to generalized interactions in response to a relatively similar source of immune pressure, important for the development of broader treatment strategies against persistent virus.
