Also, another study conducted by our laboratory indicated that the CRF07_BC recombinant strains, with relatively lower net charges in the V3 loop, exclusively utilize the CCR5 co-receptor for infection, exhibit slow replication kinetics in the primary target cells, and may be superior to other HIV-1 subtypes in initiating blood-borne infection in high-risk populations in China28. This evidence concerns the gene CCR5 and infection.