We finally found the "secret door" that a common childhood virus uses to sneak into human cells.
bioRxiv · March 13, 2026 · 10.64898/2026.03.12.711364
Why it matters
Despite being a well-known pathogen, the specific 'gateway' receptor (VP1uR) that targets it to blood cells was unknown for decades. Identifying Transferrin Receptor 1 as the key finally explains the virus's specific tissue targeting and provides a target for new treatments.
From the abstract
Human parvovirus B19 (B19V) exhibits a strict tropism for erythroid progenitor cells, which is governed by the VP1 unique region (VP1u). This region mediates cell-specific uptake by interacting with an unknown cellular receptor, termed VP1uR. Proximity labeling in permissive erythroid cells identified transferrin receptor 1 (TfR1/CD71) as the predominant membrane protein associated with VP1u. VP1u constructs colocalized with TfR1 at the cell surface of erythroid cells. Incubation with anti-TfR1