SCID-hu mice with co-implants of fetal human thymus and liver experimentally infected with tissue culture-adapted WT (Chicago-1) and WT (Bilthoven), but not vaccine (Moraten), strains of MeV show infection of thymic epithelial and myelomonocytic cells and rapid depletion of CD4+CD8+ double positive (DP) thymocytes by apoptosis [40]. Here, CD4 is linked to infection.