Accordingly, transfection of a Siglec-1 expression vector into Raji cells significantly increased their capacity for HIV-1 trans-infection to a reporter CD4+ cell line (Figure 5F), and this effect was again abolished by pre-incubation of transfected cells with the mAb 7D2 (p<0.0001; Figure 5F). This evidence concerns the gene CD4 and infection.