Further Evidence that Human Endogenous Retrovirus K102 is a Replication Competent Foamy Virus that may Antagonize HIV-1 Replication

What is it about?

Previously we reported the replication activity of HERV-K102 in patients with HIV-1. Since HERV-K102 is a foamy virus, all plasma testing was performed on DNA extracted from plasma and excess DNA HERV-K102 pol signals over normal were quantitated with a novel qPCR ddCt method. Since in HIV-1 patients, the levels of presumptive particles detected were relatively low when compared with patients with other bloodborne pathogens, it was important to confirm that the excess signal was not genomic. We showed the signal was in fact cDNA by using UNG in the mastermix buffer which digested the cDNA and the excess DNA signal. Here we report on the expression of HERV-K102 RNA in foamy macrophages which produce excessively high numbers of particles. We confirm the expression and processing of Env and that staining by immunohistology was in the foamy macrophages. Finally we showed that there was increased integration in vitro consistent with HERV-K102 replication in vitro. We also examined a cohort of commercial sex workers, known to be resistant to HIV-1 infection (HESN: HIV exposed and seronegative), and increased integration (about 5 fold over normal) was found, which was not detected in HIV-1 infected patients. Since 80% of the HESN showed increased integration, these findings suggest high levels of HERV-K102 replication may commonly inhibit HIV-1 acquisition. When considered with the accumulating evidence for T and B cell responses against HERV-K102 Env and which clears HIV-1 infected cells, it appears HERV-K102 may be HIV-1's nemesis.

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