**Question:** The antiretroviral drug that can bind to both CCR2 and CCR5 is -

A. Maraviroc
B. Atazanavir
C. Indinavir
D. Raltegravir

**Core Concept:** CCR2 and CCR5 are chemokine receptor subtypes that play a crucial role in the entry of human immunodeficiency virus (HIV) into host cells. Chemokine receptors are a family of G-protein coupled receptors (GPCRs) that are involved in immune cell trafficking and activation. CCR5 is a co-receptor for HIV entry into T cells, while CCR2 is involved in monocyte recruitment to sites of inflammation. Antiretroviral drugs targeting these receptors can be of great importance in HIV therapy.

**Why the Correct Answer is Right:** Maraviroc is a CCR5 antagonist that specifically binds to CCR5 and blocks the interaction between CCR5 and HIV gp120, preventing HIV entry into CD4+ T cells. As a result, maraviroc helps to suppress HIV replication and progression of HIV infection.

**Why Each Wrong Option is Incorrect:**

Atazanavir is an HIV protease inhibitor that targets the viral protease enzyme, inhibiting the processing of Gag and Pol polyproteins into functional viral proteins. Atazanavir does not target CCR2 or CCR5, making it an incorrect choice for the antiretroviral drug targeting both receptors.

Indinavir is another HIV protease inhibitor that works by inhibiting the HIV protease enzyme responsible for cleaving Gag and Pol polyproteins into functional viral proteins. Similar to atazanavir, indinavir does not target CCR2 or CCR5, rendering it an incorrect choice for the desired drug.

D. Raltegravir is an HIV integrase inhibitor that targets the viral integrase enzyme, which is responsible for inserting HIV DNA into the host cell genome. Raltegravir is effective against HIV types 1 and 2 but does not target CCR2 or CCR5, making it an incorrect choice for the antiretroviral drug targeting both receptors.

**Clinical Pearl:** Understanding the pharmacology of antiretroviral drugs is essential for effective HIV treatment. Combination therapy, including drugs targeting different stages of the HIV life cycle, is crucial for managing HIV infection and preventing drug resistance. Maraviroc is one of the few antiretroviral drugs that specifically targets CCR5, making it a valuable component in HIV treatment regimens.