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bioRxiv · 10.64898/2026.10.23.761412

Neonatal T cell maternal microchimerism is common and associates with early pregnancy SARS2 vaccination

Weaver, J.·Houck, J.·Jiang, Y.·Tobey, C.·Wong, J.·Shree, S.·Harrington, W. E.
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Abstract

The fetus acquires a graft of maternal cells in utero, known as maternal microchimerism (MMc), which may be enriched for T cells. However, little is known regarding the determinants of T cell trafficking into the fetus or regarding the prevalence of T cell MMc in healthy neonates. Using a closely followed cohort, we determined the association between maternal vaccination and acute infection and the detection of T cell MMc in cord blood, as measured using polymorphism-specific qPCR. We identified an association between early pregnancy SARS2 mRNA vaccination, a potent T cell stimulus, and increased detection of T cell MMc.

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Weaver, J., Houck, J., Jiang, Y., Tobey, C., Wong, J., Shree, S., Harrington, W. E.. 2026-10-28. Neonatal T cell maternal microchimerism is common and associates with early pregnancy SARS2 vaccination. https://doi.org/10.64898/2026.10.23.761412

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