The body stores white blood cells in different places, known as lymphoid organs. An antigen is any substance that can spark an immune response. In many cases, an antigen is a bacterium ...

These are sometimes called fourth-generation tests. One distinctive HIV antigen is a viral protein called p24, a structural protein that makes up most of the HIV viral core, or 'capsid'. High levels ...

They need to hunt for clues. One way they can do that is with a carcinoembryonic antigen test. It measures a protein called CEA in the blood. People with some types of cancers have higher than ...

For years, scientists worldwide have been experimenting with messenger RNA (mRNA) vaccines, unable to secure the funding or ...