However, many hurdles, such as efficient engraftment, self-renewal, and linage cell differentiation, sustainable transgene expression, avoidance of potential insertion mutagenesis, have to be worked out in HIV-1 infection humanized mouse models or SHIV infection macaque models before the clinical efficacy of GPI-scFv X5 or GPI-HCDR3 PG16-transduced hematopoietic progenitor cells or human primary CD4+ T cells can be tested in human patients. The gene discussed is CD4; the disease is HIV-1 infection.