Provirus Mutations of Human T-Lymphotropic Virus 1 and 2 (HTLV-1 and HTLV-2) in HIV-1-Coinfected Individuals Karoline Rodrigues Campos, a Adele Caterino-de-Araujo a a Laboratório de Pesquisa em HTLV, Centro de Imunologia, Instituto Adolfo Lutz, Coordenadoria de Controle de Doenças, Secretaria de Estado da Saúde, São Paulo, Brazil Karoline Rodrigues Campos and Adele Caterino-de-Araujo contributed equally to this work. Author order was determined by order of increasing seniority. ABSTRACT Provirus mutations of human T-lymphotropic virus 1 (HTLV-1), mostly the lack of the 5= long terminal repeat (LTR) genomic region, have been described and associated with severe adult T cell leukemia/lymphoma (ATLL), non-sense point mutations with low proviral load, and Western blotting indeterminate results. Until now, no information concerning provirus mutations of HTLV-2 and its consequences, as well as those of HTLV-1/2 in HIV-coinfected individuals, had been described. Therefore, we searched for these mutations in provirus samples of 44 HIV/HTLV-1- and 25 HIV/HTLV-2-coinfected individuals. Using protocols well established for ampli- fication and sequencing of segments of the LTR, env, and tax regions, we searched for defective type 1 particles that retain LTRs and lack internal sequences and type 2 particles that lack the 5=LTR region. In addition, using as references the prototypes ATK (HTLV-1) and Mo (HTLV-2), we searched for point mutations in the LTR and syn- onyms and nonsynonymous mutations and non-sense mutations in env and tax re- gions. Defective HTLV-1 and HTLV-2 provirus type 1 or 2 was detected in 31.8% of HIV/HTLV-1- and 32.0% of HIV/HTLV-2-coinfected individuals. Synonymous and non- synonymous mutations were identified mostly in HTLV-2 and associated with lower levels of specific antibodies. No non-sense mutations that resulted in premature ter- mination of Env and Tax proteins were detected. On the contrary, mutation in the stop codon of Tax2a produced a long protein characteristic of the HTLV-2c subtype. The clinical significance of these mutations in coinfected individuals remains to be defined, but they confirmed the lower sensitivity of serological and molecular diag- nostic tests in HIV/HTLV-1/2 coinfections. IMPORTANCE HTLV-1 and HTLV-2 are endemic to Brazil, and they have different ef- fects in HIV/AIDS disease progression. HIV/HTLV-1 has been described as accelerating the progression to AIDS and death, while HIV/HTLV-2 slows the progression to AIDS. Provirus mutations of HTLV-1 were implicated in severe leukemia development and in problems in the diagnosis of HTLV-1; in contrast, provirus mutations of HTLV-2 had not been confirmed and associated with problems in HTLV-2 diagnosis or dis- ease outcome. Nevertheless, data obtained here allowed us to recognize and under- stand the false-negative results in serologic and molecular tests applied for HTLV-1 and HTLV-2 diagnosis. Defective proviruses, as well as synonymous and nonsynony- mous mutations, were associated with the diagnosis deficiencies. Additionally, since HIV-1 and HTLV-1 infect the same cells (CD4 positive), the production of HIV-1 pseu- dotypes with HTLV-1 envelope glycoprotein during HIV/HTLV-1 coinfection cannot be excluded. Defective provirus of HTLV-2 and Tax2c is speculated to influence pro- gression to AIDS. KEYWORDS human T-lymphotropic virus 1, HTLV-1, human T-lymphotropic virus 2, HTLV-2, HIV, coinfection, provirus mutation, sequencing, diagnostic impairment Citation Campos KR, Caterino-de-Araujo A. 2020. Provirus mutations of human T- lymphotropic virus 1 and 2 (HTLV-1 and HTLV- 2) in HIV-1-coinfected individuals. mSphere 5:e00923-20. https://doi.org/10.1128/mSphere .00923-20. Editor Akira Ono, University of Michigan Medical School Copyright © 2020 Campos and Caterino-de- Araujo. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license. Address correspondence to Adele Caterino-de- Araujo, adele.caterino@ial.sp.gov.br. Received 10 September 2020 Accepted 13 September 2020 Published RESEARCH ARTICLE Molecular Biology and Physiology crossm September/October 2020 Volume 5 Issue 5 e00923-20 msphere.asm.org 1 30 September 2020 on October 7, 2020 by guest http://msphere.asm.org/ Downloaded from