Molluscum Contagiosum Virus Evasion of Immune Surveillance: A Review

Abstract

Background: Molluscum contagiosum (MC) is an acute infection caused by the molluscum contagiosum virus (MCV) with a worldwide incidence of approximately 8,000 cases per 100,000 individuals annually. Greater than 90% of MC cases occur in the pediatric population, and affected adults are more likely to be younger or immunocompromised. MC has minimal inflammation initially; however, a strong inflammatory response can occur during resolution of the infection, termed the beginning of the end (BOTE). MC infections may last months to years, and it is hypothesized that persistent infections may be due to suppression of immunity by MCV proteins, thus affecting MC's clinical progression. Objective: We reviewed the current proposed mechanisms of MCV immune evasion and discuss potential therapeutic options for MC treatment. Methods: A literature search was conducted using electronic databases (Pubmed, Google Scholar, Medline). Results: We compiled 18 original research articles and identified 11 proteins produced by MCV that are postulated to participate in evasion of host immunity through various molecular pathways. These proteins and/or their downstream pathways may be influenced by MC treatments in phase 3 development, including berdazimer gel 10.3% and VP-102 cantharidin, 0.7%. Conclusion: MCV is distinctive in evading immune surveillance by inhibiting or dampening several immune pathways via the production of viral proteins. The result is decreasing local inflammatory response which contributes to the prolonged survival of MCV in the epidermis. Persistent MC can be a nuisance for some patients and treatment may be desired. Currently, no treatment has been approved by the US Food and Drug Administration (FDA). Two approaches in the pipeline may affect the immune avoidance mechanisms; nevertheless, their exact mechanisms between the potential therapeutics and viral proteins remain enigmatic.

The Antiviral Effect of Berdazimer Sodium on Molluscum Contagiosum Virus Using a Novel In Vitro Methodology

“…Developing new MCV therapeutic strategies is challenging due to the lack of suitable animal and tissue culture models in which to study the virus' full replicative cycle. In tissue culture, MCV has been shown to enter cells and expresses early genes but does not undergo genome replication and the subsequent steps of virion assembly and release [9] Much of our knowledge of the MCV replicative cycle is inferred from studies on the related poxvirus vaccinia [10]. Furthermore, vaccinia virus has served as a surrogate for the study of MCV proteins, including the immune evasion proteins MC159 and MC160.…”