The ability of MAs to elicit CD4-, CD8-double negative T cells by means of their presentation on CD1b proteins of dendritic cells (Beckman et al., 1994) may well be the reason that antibody binding to MAs in AIDS patients with even very low CD4 T cell counts is maintained, relative to other patients that are not infected with HIV, or have normal CD4 T cell counts (Schleicher et al., 2002). The gene discussed is CD4; the disease is AIDS.