Human cytomegalovirus (CMV) is the most common infectious cause of infant brain damage and posttransplant complications worldwide. Despite the high global burden of disease, vaccine development to prevent infection remains hampered by challenges in generating protective immunity. The most efficacious CMV vaccine candidate tested to date is a soluble glycoprotein B (gB) subunit vaccine with MF59 adjuvant (gB/MF59), which achieved 50% protection in multiple historical phase 2 clinical trials. The vaccine-elicited immune responses that conferred this protection have remained unclear. We investigated the humoral immune correlates of protection from CMV acquisition in populations of CMV-seronegative adolescent and postpartum women who received the gB/MF59 vaccine. We found that gB/MF59 immunization elicited distinct CMV-specific immunoglobulin G (IgG)–binding profiles and IgG-mediated functional responses in adolescent and postpartum vaccinees, with heterologous CMV strain neutralization observed primarily in adolescent vaccinees. Using penalized multiple logistic regression analysis, we determined that protection against primary CMV infection in both cohorts was associated with serum IgG binding to gB present on a cell surface but not binding to the soluble vaccine antigen, suggesting that IgG binding to cell-associated gB is an immune correlate of vaccine efficacy. Supporting this, we identified gB-specific monoclonal antibodies that differentially recognized soluble or cell-associated gB, revealing that there are structural differences in cell-associated and soluble gB are relevant to the generation of protective immunity. Our results highlight the importance of the native, cell-associated gB conformation in future CMV vaccine design.

Human immunodeficiency virus (HIV-1) infection causes chronic inflammation. COX-2 derived prostaglandin E2 (PGE2) has been linked to both inflammation and carcinogenesis. We hypothesized that HIV-1 could induce COX-2 in cervical tissue and increase systemic PGE2 levels and that these alterations could play a role in AIDS-related cervical cancer. Levels of cervical COX-2 mRNA and urinary PGE-M, a biomarker of systemic PGE2 levels, were determined in 17 HIV-negative women with a negative cervical HPV test, 18 HIV-infected women with a negative HPV test, and 13 HIV-infected women with cervical HPV and high-grade squamous intraepithelial lesions on cytology. Cervical COX-2 levels were significantly associated with HIV and HPV status (P=0.006 and 0.002, respectively). Median levels of urinary PGE-M were increased in HIV-infected compared to uninfected women (11.2 ng/mg creatinine vs. 6.8 ng/mg creatinine, P=0.02). Among HIV infected women, urinary PGE-M levels were positively correlated with plasma HIV-1 RNA levels (P<0.001). Finally, levels of cervical COX-2 correlated with urinary PGE-M levels (P=0.005). This study demonstrates that HIV-1 infection is associated with increased cervical COX-2 and elevated systemic PGE2 levels. Drugs that inhibit the synthesis of PGE2 may prove useful in reducing the risk of cervical cancer or systemic inflammation in HIV infected women.