CCR5: From Natural Resistance to a New Anti-HIV Strategy

Abstract

The C-C chemokine receptor type 5 (CCR5) is a key player in HIV infection due to its major involvement in the infection process. Investigations into the role of the CCR5 coreceptor first focused on its binding to the virus and the molecular mechanisms leading to the entry and spread of HIV. The identification of naturally occurring CCR5 mutations has allowed scientists to address the CCR5 molecule as a promising target to prevent or limit HIV infection in vivo. Naturally occurring CCR5-specific antibodies have been found in exposed but uninfected people, and in a subset of HIV seropositive people who show long-term control of the infection. This suggests that natural autoimmunity to the CCR5 coreceptor exists and may play a role in HIV control. Such natural immunity has prompted strategies aimed at achieving anti-HIV humoral responses through CCR5 targeting, which will be described here.

Keywords: CCR5; HIV; vaccine.

Figure 1.

Structure of the CCR5 coreceptor; the HIV binding domains (N-terminal and ECL2 domain) and the ECL1 domain are indicated.

Figure 2.

The mucosal scenario of HIV infection. Reproduced from Klasse et al., 2008 [69].

Figure 3.

Anti-CCR5 antibodies to the first extracellular loop, isolated in various cohorts of HIV-exposed or HIV-infected, Long-Term non progressing people. Modified from Pastori et al., 2006 [86].

Figure 4.

Current approaches to extracellular CCR5 blocking.