From Perplexity A.I. Are any endogenous retroviruses reactivated in AIDS and do any of them act like superantigens? Yes, several human endogenous retroviruses (HERVs) are reactivated in AIDS, particularly during HIV infection, and some evidence suggests that certain HERV proteins may have superantigen-like activity. Reactivation of HERVs in AIDS/HIV Infection HERV-K (HML-2) is the most studied family and is consistently shown to be upregulated in HIV-infected cells and patients. HIV infection increases HERV-K RNA and protein expression in various cell lines (e.g., U-87 MG, H9 T cells, MT2, Jurkat) and primary CD4+ T cells, often in a dose- and time-dependent manner. Other HERV families such as HERV-E, HERV-W, ERV-9, and subgroups of HERV-K (HML-3, HML-4, HML-10) are also upregulated in HIV infection. The HIV-1 Tat protein plays a key role in activating HERV expression by transactivating HERV-K long terminal repeats (LTRs), opening chromatin structure, and inducing transcription factors...