Each T cell has a unique TCR and it also has a unique intracellular signalling pathway.

At the site of an infection, chemokine will be recognised by chemokine receptors on activated T cells. The increased adhesion promoted by this is due to the elevated levels of the co-stimulatory molecule B7 expressed on the surface of T cells and interacting with its CD28 receptor on T cells.

Dendritic cells that have captured and are processing antigens will also be expressing the B7 co-stimulatory molecule

The TCR on a Cytotoxic T cell interacts with MHC class II presenting peptide

At the site of infection in a tissue, the expression of E-selectin on endothelial cells will be influenced by cytokines produced within the infected tissue.

The chemokine signal that enables a naive T cells to enter a lymph node is the same as that will allows that cells once activated to enter a tissue that is infected.

Engagement of TCR with MHC+peptide is all that is required to activate the T cell

All nucleated cells are able to activate a naive T cell.

Co-stimulatory molecules are always present at high levels on dendritic cells to maximise activation upon TCR engagement to MHC+peptide