Antibody bound bacteria during HPV infection and cervical dysplasia

High-risk human papillomavirus (HR-HPV) is a known cause of >95% of cervical cancer and cervical intraepithelial neoplasia (CIN). Prophylactic vaccines are available against the most carcinogenic types and are highly effective, but the number of people receiving the vaccine is low, and vaccines are ineffective in women who have already developed CIN. Initial infection of HPV results in low-grade CIN (CIN1) and is mostly cleared by the immune system. However, failure of the immune system to clear HPV can lead to chronic infection and risk of high-grade CIN (CIN2 or CIN3) or invasive cervical cancer. There is emerging evidence that the vaginal microbiome plays an important role in this process however the mechanisms linking vaginal bacteria with host responses to HPV infection and cervical neoplasia progression are underexplored. Antibody binding to microbes can alter the structure and function of the microbiome, however this has not been comprehensively characterized in the female reproductive tract. Our overall hypothesis is that the proportion, abundance and/or functional profiles of antibody bound and unbound vaginal bacteria will differ between women with and without HPV infection, as well as those with normal cervical pathology, low-grade cervical lesions, and high-grade cervical lesions. Our overall goal is to define the associations between the proportion and abundance of antibody bound and unbound bacteria and their functions in these comparison groups. In this proposal we will utilize vaginal samples already collected from a comprehensive observational cohort (THRIVE HPV) that is specifically recruiting women with an abnormal pap smear test and following them longitudinally for 2-3 years to determine HPV status and regression or progression of cervical dysplasia. We will sort bacterial cells from vaginal swab samples at baseline enrollment into antibody bound and unbound fractions, then perform metagenomics to determine the abundance, species/genera, and functions of bacteria that are associated with antibody bound or unbound bacteria in each comparison group. A unique feature of this proposal is having access to longitudinal samples from a diverse (>50% African American) cohort for this and future studies to determine antibody bound and unbound bacterial stability over time, with comprehensive medical and pathological information. To the best of our knowledge, our work will be the first to define antibody bound and unbound vaginal bacterial populations at the species/strain level in women with or without HPV infection or different cervical pathologies. We anticipate this study will reveal antibody bound bacterial populations that are associated with a healthy or diseased microenvironment that can be identified as high-risk profiles needing to be monitored for treatment or targeted for novel immunological therapeutics.