In addition, immune cells such as CD4+ T lymphocytes with reduced levels of CCR5 would be more resistant to infection.74 Furthermore, CD8+ T cells can block cell-to-cell spread of HIV-1 through CCR5-binding chemokines (i.e., MIP-1a/CCL3, MIP-1b/CCL4, and RANTES/CCL5), as these competitively inhibit HIV entry via CCR5 expression and can prevent replication and pathogenesis.16 This evidence concerns the gene CD4 and infection.