Cervical Microbiome and Response to a Human Papillomavirus Therapeutic Vaccine for Treating High-Grade Cervical Squamous Intraepithelial Lesion.

Human papillomavirus (HPV) infection is associated with the vast majority of cervical cancer cases as well as with other anogenital cancers. PepCan is an investigational HPV therapeutic vaccine for treating cervical high-grade squamous intraepithelial lesions. The present study was performed to test whether the cervical microbiome influences vaccine responses and to explore host factors as determinants of the cervical microbiome composition in women with biopsy-proven high-grade squamous intraepithelial lesions. In a recently completed Phase I clinical trial of PepCan, histological response rate of 45% (14 of 31 patients), a significant increase in circulating T-helper type 1 cells, and a significant decrease in HPV 16 viral load were reported. DNA, extracted from liquid cytology specimens collected before and after vaccinations, were amplified and then hybridized to a G4 PhyloChip assay to characterize the microbiome. We describe trends that certain bacterial taxa in the cervix may be enriched in non-responders in comparison to responders (Padj = .052 for phylum Caldithrix and Padj = .059 for phylum Nitrospirae). There was no difference in bacterial diversity between the 2 groups. A permutational analysis of variance performed for various demographic and immune parameters showed significant clustering with microbiome beta diversity for race, HPV 16 status, peripheral T-helper type 1 cells, and HLA-B40 (P = .001, .014, .037, and .024, respectively). Further analyses showed significant differences at the empirical Operational Taxonomic Unit level for race and HPV 16 status. As these results are from a small Phase I study, further studies are needed to examine the role of cervical microbiome in response to HPV therapeutic vaccines.

Hypersaline sapropels act as hotspots for microbial dark matter.

Present-day terrestrial analogue sites are crucial ground truth proxies for studying life in geochemical conditions close to those assumed to be present on early Earth or inferred to exist on other celestial bodies (e.g. Mars, Europa). Although hypersaline sapropels are border-of-life habitats with moderate occurrence, their microbiological and physicochemical characterization lags behind. Here, we study the diversity of life under low water activity by describing the prokaryotic communities from two disparate hypersaline sapropels (Transylvanian Basin, Romania) in relation to geochemical milieu and pore water chemistry, while inferring their role in carbon cycling by matching taxa to known taxon-specific biogeochemical functions. The polyphasic approach combined deep coverage SSU rRNA gene amplicon sequencing and bioinformatics with RT-qPCR and physicochemical investigations. We found that sapropels developed an analogous elemental milieu and harbored prokaryotes affiliated with fifty-nine phyla, among which the most abundant were Proteobacteria, Bacteroidetes and Chloroflexi. Containing thirty-two candidate divisions and possibly undocumented prokaryotic lineages, the hypersaline sapropels were found to accommodate one of the most diverse and novel ecosystems reported to date and may contribute to completing the phylogenetic branching of the tree of life.