Our Research
The Kaul Lab performs translational research focused on host susceptibility to viral infections. Since most viral infections are acquired across a mucosal surface, the lab has a particular focus on the mucosal immunology and mucosal microbiome of the female and male genital tract, and more recently on the nose. The main virus that we study is HIV, but projects also examine susceptibility to and mucosal pathogenesis of HPV, Herpes simplex virus type 2 (HSV-2), Influenza, SARS-CoV-2 and bacterial STIs. This work involves translational studies that are based in participant cohorts from Canada, Kenya, Uganda and the US.
Current Projects
Impact of penile-vaginal sex on genital immunology and microbiome exchange:
Although much past research has focused on how the genital microbiome and genital immunology affect the sexual transmission viruses such as HIV, surprisingly little work has studied how sex itself changes these parameters. We are involved in two very novel studies, one of which is assessing the impact of penile-vaginal sex on genital immunology and microbiome exchange in established couples, and the other assessing how sexual debut alters the penile microbiome and immune markers of HIV susceptibility in adolescent males.
Clinical studies of microbiome-targeting interventions:
Clinical studies of microbiome-targeting interventions. Previous studies from our group and others have described that the genital (both penile and vaginal) microbiome are associated with mucosal immune differences that can either increase or decrease susceptibility to viral infections such as HIV. Several ongoing projects are elucidating how clinical interventions targeting the genital microbiome – both antibiotics targeting inflammatory bacteria and live biotherapeutics (probiotics) supplementing beneficial bacteria – affect host immune susceptibility to HIV.
Microbiome-binding host antibodies:
IgA and IgG antibodies are abundant in both nasal and genital secretions, and our recent work using a flow cytometry-based “bug flow” assay demonstrates that these frequently bind to the local microbiota. However, the role of these antibodies is not well defined, and it is unclear the degree to which they protect against colonization by non-optimal microbiome species vs. promote host immune tolerance of colonization. Ongoing projects are examining how/whether these antibodies affect the transfer of microbiome components during sex and the efficacy of vaginal live biotherapeutics (probiotics).
Planning community-informed interventions to enhance vaginal health:
In Ontario, Black women are disproportionately affected by HIV. Based on high levels of community interest, we are working with Dr. Notisha Massquoi to understand community concepts of vaginal health in Black women from Toronto, to elucidate community needs and interests in terms of possible interventions, and to better define exactly how symptoms are linked to the vaginal microbiome and immunology.
Violence and genital HIV susceptibility:
Gender-based violence is strongly linked to HIV infection for various reasons. A large project with at-risk women who sell sex in Nairobi is elucidating whether/how violence shapes immune susceptibility to HIV. We hope that this work will lead to improved strategies to reduce HIV risk after gender-based violence.
Susceptibility to respiratory viruses:
In the aftermath of the COVID-19 pandemic, we have several projects examining whether/how innate and adaptive immune parameters in the blood and in the nasal mucosa are linked to infection susceptibility, independent of vaccines, and how these are influenced by the nasal microbiome.