Defining T Cell Tissue Residency in Humans: Implications for HIV Pathogenesis and Vaccine Design

PURPOSE OF REVIEW: This review summarizes recent literature defining tissue-resident memory T cells (T(RM)) and discusses implications for HIV pathogenesis, vaccines, and eradication efforts. RECENT FINDINGS: Investigations using animal models and human tissues have identified a T(RM) transcriptional profile and elucidated signals within the tissue microenvironment leading to T(RM) development and maintenance. T(RM) are major contributors to host response in infectious diseases and cancer; in addition, T(RM) contribute to pathogenic inflammation in a variety of settings. Although T(RM) are daunting to study in HIV infection, recent work has helped define their molecular signatures and effector functions and tested strategies for their mobilization. SUMMARY: Exclusive reliance on blood sampling to gain an understanding of host immunity overlooks the contribution of T(RM), which differ in significant ways from their counterparts in circulation. It is hoped that greater understanding of these cells will lead to novel approaches to prevent and/or eradicate HIV infection.