Are t-cell receptors antibodies?

[BogMonkey]

I read that t-cells have receptors on their surface which bind to antigens. Are these receptors antibodies or are antibodies molecules which float around freely and mark antigens that they happen to bind to so that t-cells can kill them?

 

[Sorry!]

Well you are right in your comparison. They are extremely similar in nearly every way. Antibodies are secreted from B-cells and TCRs are bound to the the cell membrane and they only have a single binding site. (Antibodies have multiple forms with various binding sites 1,2-5)

http://courses.washington.edu/conj/immune/antibody.htm

^^I think that this website lays out some good knowledge on TCRs and Antibodies.

 

[AyazM]

By default, an antibody is anything that binds an antigen by recognizing it through the specific epitopes that are present. You shouldn't be too stringent about only labelling the secretions of plasma cells as antibodies as these delineations are quite blurred in actual practice. Other word you can see in usage is LIGAND. For example, RANK ligand for RANK receptor.