Modified interferon-α subtypes production and chemokine networks in the thymus during acute simian immunodeficiency virus infection, impact on thymopoiesis

• Published in: AIDS (London) Vol. 28; no. 8; pp. 1101 - 1113
• Main Authors: DUTRIEUX, Jacques, FABRE-MERSSEMAN, Véronique, CHEYNIER, Rémi, CHARMETEAU-DE MUYLDER, Bénédicte, RANCEZ, Magali, PONTE, Rosalie, ROZLAN, Sandra, FIGUEIREDO-MORGADO, Suzanne, BERNARD, Amandine, BEQ, Stéphanie, COUËDEL-COURTEILLE, Anne
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 15-05-2014; Wolters Kluwer
• Subjects: AIDS/HIV; Animals; Biological and medical sciences; CD4 Lymphocyte Count; Chemokines - metabolism; Flow Cytometry; Human viral diseases; Immunodeficiencies; Immunodeficiencies. Immunoglobulinopathies; Immunopathology; In Situ Hybridization; Infectious diseases; Interferon-alpha - metabolism; Lentivirus; Life Sciences; Macaca mulatta; Medical sciences; Polymerase Chain Reaction; Receptors, Antigen, T-Cell - metabolism; Retroviridae; RNA, Messenger - metabolism; Simian Acquired Immunodeficiency Syndrome - physiopathology; Simian Immunodeficiency Virus; Swine influenza virus; T-Lymphocytes - metabolism; Thymus Gland - physiopathology; Viral diseases; Viral diseases of the lymphoid tissue and the blood. Aids; thymus; Alpha interferon; interferon-α subtypes; Microbiological investigation; Network; Immunopathology; Thymus gland; Typing; acute viral infection; sj/bTREC ratio; thymopoiesis; Acute; Retroviridae; AIDS; chemokines; Immune deficiency; Lentivirus; Infection; Virus; Chemokine; physiopathology; HIV; Viral disease; Human immunodeficiency virus; TREC; Simian immunodeficiency virus; Subtype
• ISSN: 0269-9370; 1473-5571
• DOI: 10.1097/QAD.0000000000000249

Thymus dysfunction characterizes human/simian immunodeficiency virus (SIV) infections and contributes to physiopathology. However, both the mechanisms involved in thymic dysfunction and its precise timing remain unknown. We here analyzed thymic function during acute SIV infection in rhesus macaques.
Rhesus macaques were intravenously infected with SIVmac251 and bled every 2/3 days or necropsied at different early time points postinfection. Naive T-cell counts were followed by flow cytometry and their T-cell receptor excision circle content evaluated by qPCR. Thymic chemokines were quantified by reverse transcription-qPCR and localized by in-situ hybridization in thymuses collected at necropsy. Thymic interferon alpha (IFN-α) subtype production was quantified by reverse transcription-qPCR combined to heteroduplex tracking assay. The effect of thymic IFN-α subtypes was tested on sorted triple negative thymocytes cultured on OP9-hDL1 cells.
A reduced intrathymic proliferation history characterizes T cells produced during the first weeks of infection. Moreover, we evidenced a profound alteration of both chemokines and IFN-α subtypes transcriptional patterns in SIV-infected thymuses. Finally, we showed that IFN-α subtypes produced in the infected thymuses inhibit thymocyte proliferation, still preserving their differentiation capacity.
Thymopoiesis is deeply impacted from the first days of SIV infection. Reduced thymocyte proliferation - a time-consuming process - together with modified chemokine networks is consistent with thymocyte differentiation speed-up. This may transiently enhance thymic output, thus increasing naive T-cell counts and diversity and the immune competence of the host. Nonetheless, long-lasting modification of thymic physiology may lead to thymic exhaustion, as observed in late primary HIV infection.