To address this issue, CD4−CD8− and CD4+CD8+ thymocytes were purified by cell sorting from both normal and chagasic thymuses at day 14 post-infection and the role of S1P receptors in mediating cell chemotaxis to S1P was compared on a per cell basis by using an in vitro transwell migration assay. The gene discussed is MBTPS1; the disease is infection.