To analyse whether PC-PLC and ASM are activated downstream of HSPGs, two different experimental approaches were taken: ASM activity was assessed in HBMEC infected in the presence of heparin that blocks possible Opc-HSPG interactions, or cells were treated with heparinase III, which cleaves heparan sulphate moieties, prior to infection. The gene discussed is HSPG2; the disease is infection.