Question

Which integrin expressed on the surface of the naive T-lymphocyte allows anchoring to the high endothelial cell? What receptor does it bind to?

a) LFA-1; ICAM-1
b) VLA-4; VCAM-1
c) CD3; CD28
d) PD-1; PD-L1

Answer 1

The integrin expressed on naive T-lymphocytes for anchoring to high endothelial cells is VLA-4, which binds to VCAM-1. Other fundamental T-cell interactions include binding of TCRs to MHC II on APCs, and CD8+ T cells (CTLs) using MHC I molecules.

Step-by-step explanation:

The integrin expressed on the surface of the naive T-lymphocyte that allows anchoring to the high endothelial cell is VLA-4; it binds to the receptor VCAM-1. This interaction is crucial for the migration of T-lymphocytes to sites of inflammation during an immune response. In contrast, LFA-1 (lymphocyte function-associated antigen 1) binds ICAM-1 (intercellular adhesion molecule 1), which also contributes to T-cell adhesion to endothelial cells, but is not the primary integrin for naive T-lymphocytes.

To address the other parts of related questions:

• The TCR (T-cell receptor) of a helper T cell binds to antigens presented with MHC II molecules.
• Immune cells that bind MHC molecules on APCs (antigen-presenting cells) via CD8 coreceptors are cytotoxic T lymphocytes (CTLs).
• MHC I molecules are found on all nucleated cells, whereas MHC II molecules are typically found on professional APCs.

All these interactions are fundamental to T-cell function and the adaptive immune response, enabling T cells to recognize and respond to antigens.