HIV-1 infection.

In the depicted experiment, the peripheral blood cells in the buffy coat of a normal individual were placed in culture for 3 weeks. Immediately after sorting, the CD3⁻/CD4⁺/CD117⁺ population of in vitro–generated MCs/basophils was examined for its susceptibility to HIV-1. Three, 6, and 12 days after infection, samples of the cultures were evaluated for the presence of the viral protein p24 (A) and the viral “LTR/gag” genomic fragment (B). For a positive control in the polymerase chain reaction assay, replicate samples of the isolated genomic DNA were evaluated for the presence of the humanβ-globin gene. Molecular weight standards (Std) are indicated on the right. MCs/basophils freshly isolated from a patient with an allergic drug reaction and a patient with asthma also were found to be susceptible to the BAL strain of HIV-1 (data not shown). In those latter 2 experiments, the sorted CD3⁻/CD4⁺/CD117⁺ in vivo–differentiated MCs/basophils were exposed to the retrovirus immediately after their purification from the peripheral blood. As assessed immunohistochemically, less than 1% of the cells in the varied sorted population used in these HIV-1 susceptibility studies expressed CD3 and only about 1.5% expressed CD68.