Lymphocyte Trafficking

Naive T lymphocytes leave blood stream across the specialised endotherlial wall o blood vessel called High endothelial venule(HEV).
The specialized endothelium synthesis number of molecules which are involved in lymphocyte homing in the lymph node.In particlualr homing receptor GLYCAM1 and ICAM-1 and chemokine such as MIP3 beta.
Initial binding of Naive T cells to the vascular endothelium is mediated by L-selectin binding to GLYCAM1 ,subsequently chemokine binding occurs which triggers binding of intergin LFA-1 to its ligand ICAM1.

Lymphocytes are able to migrate across endothelium and into T cell area of lymph node.
Naive T cells can inspect Dendritic Cells in the lymph node for the presence of specific antigens.If T cells didn't recognise antigen,then T cells are not activated and passed out of lymph node to return to the circulation.
T cells that don meet the speciic antigen in the lymph node are activated and begins to proliferate and mature into effector cells.