Indicate whether each of the following cell-surface proteins is expressed mainly by B cells (B), dendritic cells (D), or T cells (T). Your answer would be a four-letter string composed of letters B, D, and T only, e.g. DBBB.
( ) Co-stimulatory protein B7, which is recognized by CD28
( ) Invariant CD3 complex
( ) Inhibitory CTLA4 protein
( ) CD40 receptor, which recognizes the co-stimulatory protein CD40 ligand on a helper T cell

Question

Indicate whether each of the following cell-surface proteins is expressed mainly by B cells (B), dendritic cells (D), or T cells (T). Your answer would be a four-letter string composed of letters B, D, and T only, e.g. DBBB.
( )	Co-stimulatory protein B7, which is recognized by CD28
( )	Invariant CD3 complex
( )	Inhibitory CTLA4 protein
( )	CD40 receptor, which recognizes the co-stimulatory protein CD40 ligand on a helper T cell

Quizplus · Accepted Answer

Transmembrane B7 proteins are co-stimulatory signals on the surface of dendritic cells that are recognized by the co-receptor protein CD28 on the surface of naïve T cells. Similarly, the CD40 ligand on an effector helper T cell is recognized by CD40 receptors on B cells. T cells express the inhibitory protein CTLA4 on their surface to help regulate their activity. The CD3 complex associated with T cell receptors (TCRs) in T cells help relay the signal into the cell upon TCR stimulation by antigen binding.

Indicate Whether Each of the Following Cell-Surface Proteins Is Expressed