Development of a human papillomavirus (HPV) multiplex immunoassay to profile HPV antibodies.

Neutralizing antibodies (NAbs) are considered the primary mechanism of vaccine-mediated protection against human papillomaviruses (HPV), the causative agent of cervical cancer. However, the minimum level of NAb needed for protection is currently unknown. The HPV pseudovirion-based neutralization assay (PBNA) is the gold standard method for assessing HPV antibody responses but is time-consuming and labor-intensive. With the development of higher valency HPV vaccines, alternative serological assays with the capacity for multiplexing would improve efficiency and output. Here we describe a multiplex bead-based immunoassay to characterize the antibody responses to the seven oncogenic HPV types (HPV16/18/31/33/45/52/58) contained in the current licensed nonavalent HPV vaccine. This assay can measure antibody isotypes and subclasses (total IgG, IgM, IgA1-2, IgG1-4), and can be adapted to measure other antibody features (e.g., Fc receptors) that contribute to vaccine immunity. When tested with serum samples from unvaccinated and vaccinated individuals, we found high concordance between HPV-specific IgG using this multiplex assay and NAbs measured with PBNA. Overall, this assay is high-throughput, sample-sparing, and time-saving, providing an alternative to existing assays for the measurement and characterization of HPV antibody responses.

No woman left behind: achieving cervical cancer elimination among women living with HIV.

Cervical cancer is the fourth most common malignancy in women of reproductive age globally. The burden of this disease is highest in low-income and middle-income countries, especially among women living with HIV. In 2018, WHO launched a global strategy to accelerate cervical cancer elimination through rapid scale-up of prophylactic vaccination, cervical screening, and treatment of precancers and cancers. This initiative was key in raising a call for action to address the stark global disparities in cervical cancer burden. However, achieving elimination of cervical cancer among women with HIV requires consideration of biological and social issues affecting this population. This Position Paper shows specific challenges and uncertainties on the way to cervical cancer elimination for women living with HIV and highlights the scarcity of evidence for the effect of interventions in this population. We argue that reaching equity of outcomes for women with HIV will require substantial advances in approaches to HPV vaccination and improved understanding of the long-term effectiveness of HPV vaccines in settings with high HIV burden cervical cancer, just as HIV, is affected by social and structural factors such as poverty, stigma, and gender discrimination, that place the elimination strategy at risk. Global efforts must, therefore, be galvanised to ensure women living with HIV have optimised interventions, given their substantial risk of this preventable malignancy.

Investigating the effects of probiotics on pneumococcal colonization using an in vitro adherence assay.

Adherence of Streptococcus pneumoniae (the pneumococcus) to the epithelial lining of the nasopharynx can result in colonization and is considered a prerequisite for pneumococcal infections such as pneumonia and otitis media. In vitro adherence assays can be used to study the attachment of pneumococci to epithelial cell monolayers and to investigate potential interventions, such as the use of probiotics, to inhibit pneumococcal colonization. The protocol described here is used to investigate the effects of the probiotic Streptococcus salivarius on the adherence of pneumococci to the human epithelial cell line CCL-23 (sometimes referred to as HEp-2 cells). The assay involves three main steps: 1) preparation of epithelial and bacterial cells, 2) addition of bacteria to epithelial cell monolayers, and 3) detection of adherent pneumococci by viable counts (serial dilution and plating) or quantitative real-time PCR (qPCR). This technique is relatively straightforward and does not require specialized equipment other than a tissue culture setup. The assay can be used to test other probiotic species and/or potential inhibitors of pneumococcal colonization and can be easily modified to address other scientific questions regarding pneumococcal adherence and invasion.