Gut lactate-producing bacteria promote CD4 T cell recovery on Anti-retroviral therapy in HIV-infected patients

Graphical abstract
Anti-retroviral therapy (ART) effectively suppresses viral replication in HIV-infected patients, however CD4 + cell restoration to normal value is not achieved by 15–20% of patients who are called immune non-responders. Gut microbiota composition has been shown to influence host immunity. Herein, to identify intestinal microbial agents that may influence the CD4 recovery in HIV-infected patients, we utilized a “Quasi-paired cohort” method to analyze intestinal metagenome data from immunological responders (IRs) and immunological non-responders (INRs). This method identified significant enrichment for Streptococcus sp. and related lactate-producing bacteria (LAB) in IRs. In a validation cohort, positive correlations between the abundance of these LAB and the post-ART CD4 + recovery was observed, and a prediction model based on these LAB performed well in predicting immune recovery. Finally, experiments using a germ-free mouse model of antibody-induced CD4 + cell depletion showed that supplementation with a lactate-producing commensal Streptococcus thermophilus strongly promoted CD4 recovery. In conclusion, our study identified a group of LAB that was associated with enhanced immune recovery in post-ART HIV-infected patients and promotes CD4 + cell restoration in a mouse model. These findings favour supplementation of LAB commensal as a therapeutic strategy for CD4 + cell count improvement in HIV-infected patients.