Cell Host Microbe. 2019 Sep 11; 26(3):336-346.e3.

PubMed ID: 31513771

A meta-analysis of passive immunization studies shows that serum-neutralizing antibody titer associates with protection against SHIV challenge

Pegu A, Borate B, Huang Y, Pauthner MG, Hessell AJ, Julg B, Doria-Rose NA, Schmidt SD, Carpp LN, Cully MD, Chen X, Shaw GM, Barouch DH, Haigwood NL, Corey L, Burton DR, Roederer M, Gilbert PB, Mascola JR, Huang Y

Passively administered broadly neutralizing antibodies (bNAbs) targeting the HIV-1 envelope glycoprotein (Env) have been shown to protect non-human primates (NHPs) against chimeric simian-human immunodeficiency virus (SHIV) infection. With data from multiple non-human primate SHIV challenge studies that used single bNAbs, we conducted a meta-analysis to examine the relationship between predicted serum 50% neutralization titer (ID50) against the challenge virus and infection outcome. In a logistic model that adjusts for bNAb epitopes and challenge viruses, serum ID50 had a highly significant effect on infection risk (p < 0.001). The estimated ID50 to achieve 50%, 75%, and 95% protection was 91 (95% confidence interval [CI]: 55, 153), 219 (117, 410), and 685 (319, 1471), respectively. This analysis indicates that serum neutralizing titer against the relevant virus is a key parameter of protection and that protection from acquisition by a single bNAb might require substantial levels of neutralization at the time of exposure.