Low antibody-dependent cellular cytotoxicity responses in Zambians prior to HIV-1 intrasubtype C superinfection

•Plasma associated ADCC activity is low or absent prior to HIV-1 superinfection.•ADCC activity correlates with gp120 binding and virus-neutralizing antibody titers.•HIV superinfected subjects have similar titers of anti-CMV antibodies to controls.

We have previously shown that HIV-1 superinfected Zambian seroconverters mount low binding and neutralizing antibody responses to their primary HIV-1 infecting virus, which could increase susceptibility to re-infection. Here, we investigated if antibody-dependent cellular cytotoxicity (ADCC), a process by which virus-infected cells are killed, was also reduced. Superinfected individuals exhibited low ADCC activity compared to non-superinfected individuals, but similar levels of CMV-reactive binding antibodies, suggesting superinfected individuals are capable of generating and maintaining virus-specific antibodies.