Serwanga, JenniferSsemwanga, DeogratiusMuganga, MichaelNakiboneka, RitahNakubulwa, SusanKiwuwa-Muyingo, SylviaMorris, LynnRedd, Andrew D.Quinn, Thomas C.Kaleebu, Pontiano2022-08-222022-08-222018Serwanga, J., Ssemwanga, D., Muganga, M., Nakiboneka, R., Nakubulwa, S., Kiwuwa-Muyingo, S., ... & Porcella, S. F. (2018). HIV-1 superinfection can occur in the presence of broadly neutralizing antibodies. Vaccine, 36(4), 578-586. https://doi.org/10.1016/j.vaccine.2017.11.075https://doi.org/10.1016/j.vaccine.2017.11.075https://nru.uncst.go.ug/handle/123456789/4373Superinfection of individuals already infected with HIV-1 suggests that pre-existing immune responses may not adequately protect against re-infection. We assessed high-risk female sex workers initially infected with HIV-1 clades A, D or A/D recombinants, to determine if HIV-1 broadly neutralizing antibodies were lacking prior to superinfection. Methods: Six superinfected female sex workers previously stratified by HIV-1 high-risk behavior, infecting virus clade and volunteer CD4 counts were evaluated at baseline (n = 5) and at 350 days post-superinfection (n = 6); one superinfected volunteer lacked pre-superinfection plasma. Retrospective plasmas were assessed for neutralization of a multi-clade panel of 12 HIV-1 viruses before superinfection, and then at quarterly intervals thereafter. Similarly stratified singly infected female sex workers were correspondingly assessed at baseline (n = 19) and 350 days after superinfection (n = 24). Neutralization of at least 50% of the 12 viruses (broad neutralization), and geometric means of the neutralization titers (IC50) were compared before and after superinfection; and were correlated with the volunteer HIV-1 superinfection status, CD4 counts, and pseudovirus clade. Results: Preexisting broad neutralization occurred in 80% (4/5) of the superinfected subjects with no further broadening by 350 days after superinfection. In one of the five subjects, HIV-1 superinfection occurred when broad neutralization was lacking; with subsequent broadening of neutralizing antibodies occuring within 9 months and plateauing by 30 months after detection of superinfection. Clade B and C pseudoviruses were more sensitive to neutralization (13; [87%]); and (12; [80%]) than the locally circulating clades A (10; [67%]) and D (6; [40%]), respectively (p = 0.025). Low antibody titers correlated with clade D viruses and with >500 CD4 T cell counts, but not with the superinfection status. Conclusion: These data demonstrate that HIV-1 superinfection can occur both in the presence, and in the absence of broadly neutralizing antibodies.enHIV-1SuperinfectionClade AClade DBroadly neutralizing antibodiesArticle