Typing PVG.R8 and PVG.1U rats by flow cytometry. A through D show results obtained from blood samples of 4 PVG.R8 rats, and E through H show the results obtained from 4 PVG.1U rats. For each rat, 2 blood samples were tested. The top plots in each panel show the results of samples stained with rat IgG 2b FITC as isotype control, and the lower plots show samples stained with anti-rat RT1.Aa,b,l-FITC antibody. Only PVG.R8 rats stained with anti-rat RT1.Aa,b,l-FITC antibody scored positive.