Oral Presentation Lorne Infection and Immunity 2021

Microbial function and genital inflammation in young South African women at high risk of HIV infection (#17)

Arghavan Alisoltani 1 2 , Monalisa T Manhanzva 1 , Matthys Potgieter 1 , Christina Balle 1 , Liam Bell 3 , Elizabeth Ross 3 , Arash Iranzadeh 1 , Michelle du Plessis 3 , Nina Radzey 1 , Zac McDonald 3 , Bridget Calder 1 , Imane Allali 1 4 , Nicola Mulder 1 5 , Smritee Dabee 1 6 , Shaun Barnabas 1 , Hoyam Gamieldien 1 , Adam Godzik 2 , Jonathan M Blackburn 1 , David L Tabb 1 7 8 , Linda-Gail Bekker 1 9 , Heather B Jaspan 1 6 , Jo-Ann S Passmore 1 10 11 , Lindi Masson 1 10 12 13
  1. Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
  2. Division of Biomedical Sciences, University of California Riverside School of Medicine, Riverside, CA, USA
  3. Centre for Proteomic and Genomic Research, Cape Town, South Africa
  4. Department of Biology and Genomic Center of Human Pathologies, Mohammed V University in Rabat, Rabat, Morocco
  5. Centre for Infectious Diseases Research (CIDRI) in Africa Wellcome Trust Centre, University of Cape Town, Cape Town, South Africa
  6. Seattle Children's Research Institute, Seattle, USA
  7. South African Tuberculosis Bioinformatics Initiative, Stellenbosch University, Stellenbosch, South Africa
  8. DST–NRF Centre of Excellence for Biomedical Tuberculosis Research, Stellenbosch University, Stellenbosch, South Africa
  9. Desmond Tutu HIV Centre, Cape Town, South Africa
  10. Centre for the AIDS Programme of Research in South Africa, Durban, South Africa
  11. National Health Laboratory Service, Cape Town, South Africa
  12. Central Clinical School, Monash University, Melbourne, Australia
  13. Burnet Institute, Melbourne, VIC, Australia

Background: Female genital tract (FGT) inflammation is an important risk factor for HIV acquisition. The FGT microbiome is closely associated with inflammatory profile, however, the relative importance of microbial activities has not been established. Since proteins are key elements representing actual microbial functions, this study utilized metaproteomics to evaluate the relationship between FGT microbial function and inflammation in 113 young and adolescent South African women at high risk of HIV infection. Women were grouped as having low, medium or high FGT inflammation by K-means clustering according to pro-inflammatory cytokine concentrations.

Results: A total of 3,186 microbial and human proteins were identified in vaginal swabs using liquid chromatography-tandem mass spectrometry, while 94 microbial taxa were included in the taxonomic analysis. Both metaproteomics and 16S rRNA gene sequence analyses showed increased non-optimal bacteria and decreased lactobacilli in women with FGT inflammatory profiles. However, differences in the predicted relative abundance of most bacteria were observed between 16S rRNA and metaproteomics analyses. Bacterial protein functional annotations (gene ontology) predicted inflammatory cytokine profiles more accurately than bacterial relative abundance determined by 16S rRNA gene sequence analysis, and functional predictions based on 16S rRNA data (p<0.0001). The majority of microbial biological processes were underrepresented in women with high inflammation compared to those with low inflammation, including a Lactobacillus-associated signature of reduced cell wall organization and peptidoglycan biosynthesis. This signature remained associated with FGT inflammation in a subset of 74 women nine weeks later, was upheld after adjusting for Lactobacillus relative abundance, and was associated with in vitro inflammatory cytokine responses to Lactobacillus isolates from the same women. Reduced cell wall organization and peptidoglycan biosynthesis were also associated with high FGT inflammation in an independent sample of ten women.

Conclusions: Both the presence of specific microbial taxa in the FGT and their properties and activities are critical determinants of FGT inflammation. Our findings support those of previous studies suggesting that peptidoglycan is directly immunosuppressive, and identify a possible avenue for biotherapeutic development to reduce inflammation in the FGT. To facilitate further investigations of microbial activities, we have developed the FGT-METAP application that is available at (http://fgtdb.org/).