Since the majority of brain sequestered macrophages are CD11bhighCD14+F4/80+ during ECM (Fig 1A), we next examined the expression of TCRβ on CD11bhighCD14+F4/80+ macrophages in spleen tissue of ECM-susceptible C57BL/6 versus ECM-resistant Balb/c mice over the course of a Pb−A infection. The gene discussed is TRBC1; the disease is infection.