HTLV-1 Infection and Neuropathogenesis in the Context of Rag1-/-γc-/- (RAG1-Hu) and BLT Mice
- 428 Downloads
To date, the lack of a suitable small animal model has hindered our understanding of Human T-cell lymphotropic virus (HTLV)-1 chronic infection and associated neuropathogenesis defined as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The host immune response plays a critical role in the outcome of HTLV-1 infection, which could be better tested in the context of humanized (hu) mice. Thus, we employ here the Balb/c-Rag1−/−γc−/− or Rag1 as well as Bone marrow-Liver-Thymic (BLT) mouse models for engraftment of human CD34+ hematopoietic stem cells. Flow cytometry and histological analyses confirmed reconstitution of Rag1 and BLT mice with human immune cells. Following HTLV-1 infection, proviral load (PVL) was detected in the blood of Rag-1 and BLT hu-mice as early as 2 weeks post-infection (wpi) with sustained elevation in the subsequent weeks followed by Tax expression. Additionally, infection was compared between adult and neonatal Rag1 mice with both PVL and Tax expression considerably higher in the adult Rag1 mice as compared to the neonates. Establishment of peripheral infection led to lymphocytic infiltration with concomitant Tax expression and resulting myelin disruption within the central nervous system of infected mice. In addition, up-regulation in the expression of several immune checkpoint mediators such as programmed cell death-1 (PD-1), T-cell Ig and ITIM domain (TIGIT), and T cell Ig and mucin domain-3 protein (Tim-3) were observed on CD8+ T cells in various organs including the CNS of infected hu-mice. Collectively, these studies represent the first attempt to establish HTLV-1 neuropathogenesis in the context of Rag-1 and BLT hu-mice as potential novel tools for understanding HTLV-1 neuropathogenesis and testing of novel therapies such as immune checkpoint blockade in the amelioration of chronic HTLV-1 infection.
KeywordsHTLV-1 Chronic viral infection Humanized mice RAG1 BLT
These studies were supported by the National Institutes of Health (NIH) via NINDS R01NS097147-01A1 and NCI R01CA054559-20 Revised awarded to PJ. We wish to acknowledge the help of Dr. Paige Charlins and Dr. Ramesh Akkina (Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collin, USA) in hu-mice experimentation. We would also like to thank Dr. Owen Chan and Dr. Brenda Hernandez from the University of Hawaii Cancer Center Pathology Shared Resource (funded in part by NIH/NCI P30 CA071789-17 to LN) for their contributions in immunohistochemistry data.
Compliance with Ethical Standards
Conflict of Interest
The authors declare no competing financial interests.
- Akkina R, Berges BK, Palmer BE, Remling L, Neff CP, Kuruvilla J, Connick E, Folkvord J, Gagliardi K, Kassu A, Akkina SR (2011) Humanized Rag1−/− gammac−/− mice support multilineage hematopoiesis and are susceptible to HIV-1 infection via systemic and vaginal routes. PLoS One 6:e20169CrossRefPubMedPubMedCentralGoogle Scholar
- Biddison WE, Kubota R, Kawanishi T, Taub DD, Cruikshank WW, Center DM, Connor EW, Utz U, Jacobson S (1997) Human T cell leukemia virus type I (HTLV-I)-specific CD8+ CTL clones from patients with HTLV-I-associated neurologic disease secrete proinflammatory cytokines, chemokines, and matrix metalloproteinase. J Immunol 159:2018–2025PubMedGoogle Scholar
- Brunetto GS, Massoud R, Leibovitch EC, Caruso B, Johnson K, Ohayon J, Fenton K, Cortese I, Jacobson S (2014) Digital droplet PCR (ddPCR) for the precise quantification of human T-lymphotropic virus 1 proviral loads in peripheral blood and cerebrospinal fluid of HAM/TSP patients and identification of viral mutations. J Neuro-Oncol 20:341–351Google Scholar
- Dudek TE, No DC, Seung E, Vrbanac VD, Fadda L, Bhoumik P, Boutwell CL, Power KA, Gladden AD, Battis L, Mellors EF, Tivey TR, Gao X, Altfeld M, Luster AD, Tager AM, Allen TM (2012) Rapid evolution of HIV-1 to functional CD8(+) T cell responses in humanized BLT mice. Sci Transl Med 4:143ra198CrossRefGoogle Scholar
- Hindson BJ, Ness KD, Masquelier DA, Belgrader P, Heredia NJ, Makarewicz AJ, Bright IJ, Lucero MY, Hiddessen AL, Legler TC, Kitano TK, Hodel MR, Petersen JF, Wyatt PW, Steenblock ER, Shah PH, Bousse LJ, Troup CB, Mellen JC, Wittmann DK, Erndt NG, Cauley TH, Koehler RT, So AP, Dube S, Rose KA, Montesclaros L, Wang S, Stumbo DP, Hodges SP, Romine S, Milanovich FP, White HE, Regan JF, Karlin-Neumann GA, Hindson CM, Saxonov S, Colston BW (2011) High-throughput droplet digital PCR system for absolute quantitation of DNA copy number. Anal Chem 83:8604–8610CrossRefPubMedPubMedCentralGoogle Scholar
- Hyun J, Ramos JC, Toomey N, Balachandran S, Lavorgna A, Harhaj E, Barber GN (2015) Oncogenic HTLV-1 tax suppression of primary innate immune signaling pathways. J Virol 89:4880–4893Google Scholar
- Kozako T, Yoshimitsu M, Akimoto M, White Y, Matsushita K, Soeda S, Shimeno H, Kubota R, Izumo S, Arima N (2011) Programmed death-1 (PD-1)/PD-1 ligand pathway-mediated immune responses against human T-lymphotropic virus type 1 (HTLV-1) in HTLV-1-associated myelopathy/tropical spastic paraparesis and carriers with autoimmune disorders. Hum Immunol 72:1001–1006CrossRefPubMedGoogle Scholar
- Kubota R, Soldan SS, Martin R, Jacobson S (2002) Selected cytotoxic T lymphocytes with high specificity for HTLV-I in cerebrospinal fluid from a HAM/TSP patient. J Neuro-Oncol 8:53–57Google Scholar
- Levin MC, Jacobson S (1997) HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP): a chronic progressive neurologic disease associated with immunologically mediated damage to the central nervous system. J Neuro-Oncol 3:126–140Google Scholar
- Nagai M, Osame M (2003) Human T-cell lymphotropic virus type I and neurological diseases. J Neuro-Oncol 9:228–235Google Scholar
- Ndhlovu LC, Leal FE, Hasenkrug AM, Jha AR, Carvalho KI, Eccles-James IG, Bruno FR, Vieira RG, York VA, Chew GM, Jones RB, Tanaka Y, Neto WK, Sanabani SS, Ostrowski MA, Segurado AC, Nixon DF, Kallas EG (2011) HTLV-1 tax specific CD8+ T cells express low levels of Tim-3 in HTLV-1 infection: implications for progression to neurological complications. PLoS Negl Trop Dis 5:e1030CrossRefPubMedPubMedCentralGoogle Scholar
- Panfil AR, Al-Saleem JJ, Green PL (2013) Animal models utilized in HTLV-1 research. Virology (Auckl) 4:49–59Google Scholar
- Publicover J, Goodsell A, Nishimura S, Vilarinho S, Wang ZE, Avanesyan L, Spolski R, Leonard WJ, Cooper S, Baron JL (2011) IL-21 is pivotal in determining age-dependent effectiveness of immune responses in a mouse model of human hepatitis B. J Clin Invest 121:1154–1162CrossRefPubMedPubMedCentralGoogle Scholar