An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Seder RA, Paul WE, Davis MM, Fazekas de St Groth B.Seder RA, et al.J Exp Med. 1992 Oct 1;176(4):1091-8. doi: 10.1084/jem.176.4.1091.J Exp Med. 1992.PMID: 1328464Free PMC article.