The type of CD4 cell that predominantly harbors latent HIV is known as an effector memory cell, according to research findings guided by a highly precise means of sequencing the virus’ genetic code.

Effector memory cells recall previous infections as well as how to combat them, providing lifelong immunity to certain infections.

Publishing their findings in Cell Reports, researchers studied CD4 cells taken from six people with HIV who were on long-term antiretroviral treatment. The investigators used a so-called Full-Length Individual Proviral Sequencing (FLIPS) assay to sequence the virus in different subsets of these CD4 cells. FLIPS has the capacity to sequence almost the entire length of the virus’ genetic code as integrated into human cells; in this form, the genetic code is known as provirus. The assay can determine if the provirus is replication competent, meaning it is intact enough to yield new copies of HIV that can go on to infect new cells.

According to the FLIPS analysis, 5 percent of proviruses in the CD4 cells were replication competent. There was an unequal distribution of replication-competent provirus among the subtypes of CD4 cells, with effector memory cells harboring the largest proportion.

To read a press release about the study, click here.

To read the study, click here.