Journal of virology 2017 12 13() pii 10.1128/JVI.01883-17
Recently discovered broadly neutralizing anti-HIV-1 antibodies (bNAbs) demonstrate extensive breadth and potency against diverse HIV-1 strains, and represent a promising approach for the treatment and prevention of HIV-1 infection. The breadth and potency of these antibodies have primarily been evaluated using panels of HIV-1 Env-pseudotyped viruses produced in 293T cells expressing molecularly cloned Envs. Here we report on the ability of 5 bNAbs currently in clinical development to neutralize circulating primary HIV-1 isolates derived from peripheral blood mononuclear cells (PBMC), and compare the results to the pseudovirus panels used to characterize the bNAbs. The 5 bNAbs demonstrated significantly reduced breadth and potency when tested against clinical isolates produced in PBMC compared to their performance against Env-pseudotyped viruses. The magnitude of this difference in neutralizing activity varied depending on the antibody epitope. Glycan-targeting antibodies showed differences of only 3 to 4-fold while the MPER-targeting antibody 10E8 showed a nearly 100-fold decrease in activity between published Env-pseudotyped virus panels and PBMC-derived primary isolates. Utilizing clonal PBMC-derived primary isolates and molecular clones, we determined that the observed discrepancy in bNAb performance is due to the increased sensitivity to neutralization exhibited by 293T-produced Env-pseudotyped viruses. We also found that while full-length molecularly cloned viruses produced in 293T cells exhibit increased sensitivity to neutralization compared to PBMC-derived viruses, Env-pseudotyped viruses produced in 293T cells generally exhibit even greater sensitivity to neutralization. As the clinical development of bNAbs progresses, it will be critical to determine the relevance of each of these in vitro neutralization assays to in vivo antibody performance.ImportanceNovel therapeutic and preventative strategies will be needed to contain the HIV-1 epidemic. Antibodies with exceptional neutralizing activity against HIV-1 may provide several advantages to traditional HIV drugs, including an improved side effect profile, reduced dosing frequency, and immune enhancement. The activity of these antibodies has been established in vitro utilizing HIV-1 Env-pseudotyped viruses derived from circulating viruses but produced in 293T cells by pairing Envs with a backbone vector. We tested PBMC-produced circulating viruses against 5 anti-HIV-1 antibodies currently in clinical development. We found that the activity of these antibodies is significantly reduced against PBMC isolates as compared to 293T Env-pseudotyped viruses. This decline varied among the antibodies tested, with some demonstrating moderate reductions in activity while others showing almost 100-fold reduction. As the development of these antibodies progresses, it will be critical to determine how the results of different in vitro tests correspond to performance in the clinic.