Figure 1

Double staining of a sentinel node for CD4 (brown staining) and CD28 (red staining).1a). Primary follicle showing a high expression of CD28.1b). Primary follicle showing a low expression of CD28. 1c). Germinal center showing a moderate expression of CD28. 1d). Germinal center showing a low expression of CD28. 1e). Paracortical area showing a moderate expression of CD28. 1f). Paracortical area showing a low expression of CD28. 1g). Double staining of a sentinel node for CD3 (brown staining) and the zeta chain (red staining). Paracortical area showing a low expression of the zeta chain. 1h). Double staining of a sentinel node for CD8 (brown staining) and CD28 (red staining). Corresponding paracortical area showing a high expression of CD28.