Madhi, Shabir A.McMahon, William C.Kwatra, GauravIzu, AlaneJones, Stephanie A.Mbele, Nkululeko J.Jafta, NwabisaLala, RushilShalekof, SharonTiemessen, Caroline T.Nunes, Marta C.2024-10-032024-10-032024-09McMahon, W. C., Kwatra, G., Izu, A., Jones, S. A., Mbele, N. J., Jafta, N., Lala, R., Shalekoff, S., Tiemessen, C. T., Madhi, S. A., & Nunes, M. C. (2024). T-cell responses to ancestral SARS-CoV-2 and Omicron variant among unvaccinated pregnant and postpartum women living with and without HIV in South Africa. Scientific reports, 14(1), 20348. https://doi.org/10.1038/s41598-024-70725-82045-2322 (online)10.1038/s41598-024-70725-8https://hdl.handle.net/10539/41330SARS-CoV-2 cell-mediated immunity remains understudied during pregnancy in unvaccinated Black African women living with HIV (WLWH) from low- and middle-income countries. We investigated SARS-CoV-2-specifc T-cell responses 1 month following infection in 24 HIV-uninfected women and 15 WLWH at any stage during pregnancy or postpartum. The full-length spike (FLS) glycoprotein and nucleocapsid (N) protein of wild-type (WT) SARS-CoV-2, as well as mutated spike protein regions found in the Omicron variant (B.1.1.529) were targeted by flow cytometry. WT-specific CD4+and CD8+T cells elicited similar FLS- and N-specific responses in HIV-uninfected women and WLWH. SARS-CoV 2-specifc T-lymphocytes were predominantly TNF-α monofunctional in pregnant and postpartum women living with and without HIV, with fever cells producing either IFN-γ or IL-2. Furthermore, T-cell responses were unaffected by Omicron-specific spike mutations as similar responses between Omicron and the ancestral virus were detected for CD4+ and CD8+ T cells. Our results collectively demonstrate comparable T-cell responses between WLWH on antiretroviral therapy and HIV-uninfected pregnant and postpartum women who were naïve to Covid-19 vaccination. Additionally, we show that T cells from women infected with the ancestral virus, Beta variant (B.1.351), or Delta variant (B.1.617.2) can cross-recognize Omicron, suggesting an overall preservation of T-cell immunity.en© The Author(s) 2024. Open Access, This article is licensed under a Creative Commons Attribution 4.0 International License.T- CellSARS‑CoV‑2Omicron variantPregnant womenPostpartum womenHIVSouth AfricaSDG-3: Good health and well-beingArticle