Mechanisms of Rhinovirus Neutralisation by Antibodies.

Antibodies are a critical immune correlate of protection for rhinoviruses, particularly those antibodies found in the secretory compartment. For nonenveloped viruses such as rhinoviruses, antibody binding to regions of the icosahedral capsid can neutralise infections by a number of different mechanisms. The purpose of this review is to address the neutralising mechanisms of antibodies to rhinoviruses that would help progress vaccine development. At least five mechanisms of antibody neutralisation have been identified which depend to some extent on the antibody binding footprints upon the capsid. The most studied mechanisms are virion aggregation, inhibition of attachment to cells, and stabilisation or destabilisation of the capsid structure. Newer mechanisms of degradation inside the cell through cytoplasmic antibody detection or outside by phagocytosis rely on what might have been previously considered as non-neutralising antibodies. We discuss these various approaches of antibody interference of rhinoviruses and offer suggestions as to how these could influence vaccine design.

An investigation of rhinovirus infection on cellular uptake of poly (glycerol-adipate) nanoparticles.

Viral infections represent 44% of newly emerging infections, and as is shown by the COVID-19 outbreak constitute a major risk to human health and wellbeing. Although there are many efficient antiviral agents, they still have drawbacks such as development of virus resistance and accumulation within off-target organs. Encapsulation of antiviral agents into nanoparticles (NPs) has been shown to improve bioavailability, control release, and reduce side effects. However, there is little quantitative understanding of how the uptake of NPs into virally infected cells compares to uninfected cells. In this work, the uptake of fluorescently labeled polymer NPs was investigated in several models of rhinovirus (RV) infected cells. Different multiplicities of RV infections (MOI) and timings of NPs uptake were also investigated. In some cases, RV infection resulted in a significant increase of NPs uptake, but this was not universally noted. For HeLa cells, RV-A16 and RV-A01 infection elevated NPs uptake upon increasing the incubation time, whereas at later timepoints (6 h) a reduced uptake was noted with RV-A01 infection (owing to decreased cell viability). Beas-2B cells exhibited more complex trends: decreases in NPs uptake (cf. uninfected cells) were observed at short incubation times following RV-A01 and RV-A16 infection. At later incubation times (4 h), we found a marked decrease of NPs uptake for RV-A01 infected cells but an increase in uptake with RV-A16 infected cells. Where increases in NPs uptake were found, they were very modest compared to results previously reported for a hepatitis C/ Huh7.5 cell line model. An increase in RV dose (MOI) was not associated with any notable change of NPs uptake. We argue that the diverse endocytic pathways among the different cell lines, together with changes in virus nature, size, and entry mechanism are responsible for these differences. These findings suggest that NPs entry into virally infected cells is a complex process, and further work is required to unravel the different factors which govern this. Undertaking this additional research will be crucial to develop potent nanomedicines for the delivery of antiviral agents.