Vγ9Vδ2 T-cells Are Potent Inhibitors of SARS-CoV-2 Replication and Represent Effector Phenotypes in Patients With COVID-19.

Vγ9Vδ2 T cells play a key role in the innate immune response to viral infections through butyrophilin 3A (BTN3A). Here, we report blood Vγ9Vδ2 T cells decreased in clinically mild COVID-19 compared to healthy volunteers, and this was maintained up to 28 days and in the recovery period. Terminally differentiated Vγ9Vδ2 T cells tended to be enriched on the day of diagnosis, 28 days after, and during the recovery period. These cells showed cytotoxic and inflammatory activities following anti-BTN3A activation. BTN3A upregulation and Vγ9Vδ2 T-cell infiltration were observed in a lung biopsy from a fatal SARS-CoV-2 infection. In vitro, SARS-CoV-2 infection increased BTN3A expression in macrophages and lung cells that enhanced the anti-SARS-CoV-2 Vγ9Vδ2 T-cell cytotoxicity and interferon-γ and tumor necrosis factor-α. Increasing concentrations of anti-BTN3A lead to viral replication inhibition. Altogether, we report Vγ9Vδ2 T cells are important in the immune response against SARS-CoV-2 infection and activation by anti-BTN3A antibody may enhance their response. Clinical Trials Registration. NCT04816760.

Protective role of macrophages from maternal-fetal interface in unvaccinated coronavirus disease 2019 pregnant women.

Pregnant women represent a high-risk population for Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection. The presence of SARS-CoV-2 has been reported in placenta from infected pregnant women, but whether the virus influences placenta immune response remains unclear. We investigated the properties of maternal-fetal interface macrophages (MFMs) in a cohort of unvaccinated women who contracted coronavirus disease 2019 (COVID-19) during their pregnancy. We reported an infiltration of CD163+ macrophages in placenta from COVID-19 women 19 whereas lymphoid compartment was not affected. Isolated MFMs exhibited nonpolarized activated signature (NOS2, IDO1, IFNG, TNF, TGFB) mainly in women infected during the second trimester of pregnancy. COVID-19 during pregnancy primed MFM to produce type I and III interferon response to SARS-CoV-2 (Wuhan and δ strains), that were unable to elicit this in MFMs from healthy pregnant women. COVID-19 also primed SARS-CoV-2 internalization by MFM in an angiotensin-converting enzyme 2-dependent manner. Activation and recall responses of MFMs were influenced by fetal sex. Collectively, these findings support a role for MFMs in the local immune response to SARS-CoV-2 infection, provide a basis for protective placental immunity in COVID-19, and highlight the interest of vaccination in pregnant women.