Massive leukocytic infiltrates at immunization sites in the skin. (A) Hematoxylin and eosin staining of the skin at the site of immunization with ovalbumin and CFA on day 7 reveals cellular infiltration of the skin. (original magnifications 5× or 100× oil objective; Zeiss Axioscope). (B) FACS analysis of cells isolated from skin site of immunization reveals consistently increased proportions of macrophages and granulocytes in skin from LTβ^−/− mice (representative of 4 experiments at days 4 and 7; n = 4 mice per group).