G1005 3

After preparation of mouse spleen slices, samples were stained with hematoxylin staining solution (Servicebio, G1005-1) for 3 to 5 min, washed with tap water, and differentiated with differentiation solution (Servicebio, G1005-3). Subsequently, the slices were washed with tap water and returned to blue with blue return solution (Servicebio, G1005-4). Next, slices were dehydrated in 85 and 95% gradient alcohol for 5 min each and stained in eosin staining solution (Servicebio, G1005-2) for 5 min. Last, slices were placed for 5 min each into anhydrous ethanol I, anhydrous ethanol II, anhydrous ethanol III, xylene I, and xylene II transparent; then, the slices were sealed with neutral gum. Image acquisition and analysis used Panoramic slice scanner and Fiji ImageJ software, respectively.