Research ArticleInfectious Disease

JC polyomavirus mutants escape antibody-mediated neutralization

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Science Translational Medicine  23 Sep 2015:
Vol. 7, Issue 306, pp. 306ra151
DOI: 10.1126/scitranslmed.aab1720

Opportunity knocks for JC polyomavirus therapy

JC polyomavirus (JCV) can be found in the urinary tract in most adults, resulting in a persistent but asymptomatic infection. However, in immunocompromised individuals, JCV opportunistically infects the brain, resulting in the debilitating and frequently fatal disease progressive multifocal leukoencephalopathy (PML). No treatments are currently available for PML, but two papers now identify and exploit a gap in the immune response to JCV. Ray et al. report that JCV strains found in the cerebrospinal fluid of PML patients have mutations that prevent antibody neutralization and that these blind spots can be overcome with vaccination. Jelcic et al. suggest that broadly neutralizing antibodies derived from a patient who recovered from PML may fill this gap.


JC polyomavirus (JCV) persistently infects the urinary tract of most adults. Under conditions of immune impairment, JCV causes an opportunistic brain disease, progressive multifocal leukoencephalopathy (PML). JCV strains found in the cerebrospinal fluid of PML patients contain distinctive mutations in surface loops of the major capsid protein, VP1. We hypothesized that VP1 mutations might allow the virus to evade antibody-mediated neutralization. Consistent with this hypothesis, neutralization serology revealed that plasma samples from PML patients neutralized wild-type JCV strains but failed to neutralize patient-cognate PML-mutant JCV strains. This contrasted with serological results for healthy individuals, most of whom robustly cross-neutralized all tested JCV variants. Mice administered a JCV virus-like particle (VLP) vaccine initially showed neutralizing “blind spots” (akin to those observed in PML patients) that closed after booster immunization. A PML patient administered an experimental JCV VLP vaccine likewise showed markedly increased neutralizing titer against her cognate PML-mutant JCV. The results indicate that deficient humoral immunity is a common aspect of PML pathogenesis and that vaccination may overcome this humoral deficiency. Thus, vaccination with JCV VLPs might prevent the development of PML.

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