CCL2 production in both MDMs and HeLa cells was significant (Figure 1—figure supplement 1A, B and D), but the levels of CCL2 produced in CEM-CCR5 cells was below the level of detection – and we only detected miniscule amounts upon HIV infection or robustly only in samples where CCL2 was extraneously added (Figure 1—figure supplement 1C). Here, CCR5 is linked to HIV infectious disease.