So far, the researchers assumed that coronaviruses bind to the ACE2 receptor with their spike proteins and then penetrate the cells after "activation" by the serine protease TMPRSS2. However, this was not thought far enough: In the meantime, researchers have found another factor that plays an important role.

Neuropilin-1 is produced on the cells of the upper respiratory tract, but also on blood vessels, the olfactory epithelium, as well as neurons and could explain its rapid spread in the body.

Using cell cultures, the researchers have already been able to prevent the virus from invading the body via monoclonal antibodies and with a neuropilin-1 antagonist, so that the testing of potential treatments and vaccines is now being expanded.

Original Publications:
1) Daly JL, Simonetti B, Klein K, Chen KE, Williamson MK, Antón-Plágaro C, Shoemark DK, Simón-Gracia L, Bauer M, Hollandi R, Greber UF, Horvath P, Sessions RB, Helenius A, Hiscox JA, Teesalu T, Matthews DA, Davidson AD, Collins BM, Cullen PJ, Yamauchi Y. Neuropilin-1 is a host factor for SARS-CoV-2 infection. Science. 2020 Oct 20:eabd3072. doi: 10.1126/science.abd3072. Epub ahead of print. PMID: 33082294.

2) Cantuti-Castelvetri L, Ojha R, Pedro LD, Djannatian M, Franz J, Kuivanen S, van der Meer F, Kallio K, Kaya T, Anastasina M, Smura T, Levanov L, Szirovicza L, Tobi A, Kallio-Kokko H, Österlund P, Joensuu M, Meunier FA, Butcher SJ, Winkler MS, Mollenhauer B, Helenius A, Gokce O, Teesalu T, Hepojoki J, Vapalahti O, Stadelmann C, Balistreri G, Simons M. Neuropilin-1 facilitates SARS-CoV-2 cell entry and infectivity. Science. 2020 Oct 20:eabd2985. doi: 10.1126/science.abd2985. Epub ahead of print. PMID: 33082293.

Source:
https://www.aerzteblatt.de/