Question

CD4 and CD8 are: Select one: O a Molecules present on the surface of T cells that enhance interaction with antigen presenting cells O b. Molecules present on T cells that provide co-stimulation for B cells @c. Molecules secreted by antigen-presenting cells d. Molecules present on the surface of natural killer (NK) cells e. Molecules on the surface of antigen-presenting cells that inhibit NK cell activation

Answer 1

Answer is A -- molecules present on the surface of T cells that enhance the interaction with antigen presenting cells.

The T cell receptor is expressed on the t cell surface in Association with other transmembrane molecules referred to as a co-receptor. Disco receptor can be one of the two molecules on the mature T cell: either cd4 cd8 molecule. The extracellular portions of CD4 and CD8 bind to MHC molecules on the surface of a antigen presenting cell that present antigen to T cells. CD4 binds selectively to the subset of MHC molecules known as MHC class II and CD 8 bind selectively to the subset of MHC molecule known as MHC class I.