In situ receptor autoradiography showing chemokine binding to the inflamed nonrheumatoid synovium. (a) Samples of tissue were incubated with 125I-CCL5 and subjected to autoradiography. The chemokine binds to cells in the intima (I) and the subintima (S). (b) Samples incubated with radiolabelled chemokine in the presence of 1000-fold excess homologous unlabelled chemokine show an absence of chemokine binding. Magnification × 470 (a) and (b).