White pulp of spleen (mouse)

Stain: Hematoxylin & eosin in A and alkaline phosphatase in B (with substrate Naphtol Fast Blue RR). The general structure of the white pulp of the spleen and its specific microenvironment for T and B cells is well illustrated using alkaline phosphatase that strongly stains the capillaries around the PALS area (B, 1). 1: PALS area with a central artery (T cells); The germinal centre (2) and the mantle layer (3) are the B cell areas. The marginal zone (4) usually contains also T cells between the B cells. The alkaline phosphatase reaction strongly stains the capillaries and sinuses at the border zone between red and white pulp, particularly around the PALS area. The endothelial lining of larger central arteries exhibits a strong positive red reaction product as well as the small branches in the same area. All other smaller arterioles and capillaries stained homogeneously positive. Note that the B cell area (2, 3 and 4) is mostly devoid of alkaline phosphatase activity. The outer perilymphoid zone capillaries react positively in contrast to the negative-reacting venous sinusoids.