How HIV changes its tropism: evolution and adaptation?Mosier, Donald ECurrent Opinion in HIV and AIDS: March 2009 - Volume 4 - Issue 2 - p 125–130 doi: 10.1097/COH.0b013e3283223d61 Entry inhibitors: Edited by Jose A. Esté Abstract Author Information Purpose of review To present recent information on the evolution of coreceptor use from CCR5 alone to CCR5 and CXCR4, the impact CCR5 inhibitors have on this process, and new insights into HIV-1 binding to CD4 and CCR5. Recent findings The findings that are summarized include resistance to CCR5 inhibitors, genotypic predictors of coreceptor use, the link between coreceptor use and cell tropism, and new data on CCR5 structure and function. Summary Resistance to CCR5 inhibitors is uncommon, and frequently involves selection of minor populations of R5X4 virus. Genotypic predictors of coreceptor use need to take into account the entire envelope sequence, not just V3. Genetic polymorphisms in humans that affect CCR5 or chemokines that bind CCR5 affect not only virus entry but also immune reconstitution. Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA Correspondence to Donald E. Mosier, PhD, MD, The Scripps Research Institute–IMM7, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA Tel: +1 858 784 9121; fax: +1 858 784 9190; e-mail: email@example.com © 2009 Lippincott Williams & Wilkins, Inc.