A mathematical model of HTLV-I infection with two time delays

In this paper, we include two time delays in a mathematical model for the CD8$^+$ cytotoxicT lymphocytes (CTLs) response to the Human T-cell leukaemia virus type I (HTLV-I) infection,where one is the intracellular infection delay and the other is the immune delay to account for aseries of immunolog...

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Main Authors: Xuejuan Lu, Lulu Hui, Shengqiang Liu, Jia Li
Format: Article
Language:English
Published: AIMS Press 2014-12-01
Series:Mathematical Biosciences and Engineering
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Online Access:https://www.aimspress.com/article/doi/10.3934/mbe.2015.12.431
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author Xuejuan Lu
Lulu Hui
Shengqiang Liu
Jia Li
author_facet Xuejuan Lu
Lulu Hui
Shengqiang Liu
Jia Li
author_sort Xuejuan Lu
collection DOAJ
description In this paper, we include two time delays in a mathematical model for the CD8$^+$ cytotoxicT lymphocytes (CTLs) response to the Human T-cell leukaemia virus type I (HTLV-I) infection,where one is the intracellular infection delay and the other is the immune delay to account for aseries of immunological events leading to the CTL response. We show that the global dynamicsof the model system are determined by two threshold values $R_0$, the correspondingreproductive number of a viral infection, and $R_1$, the corresponding reproductive numberof a CTL response, respectively. If $R_0<1$, the infection-free equilibrium is globallyasymptotically stable, and the HTLV-I viruses are cleared. If $R_1 < 1 < R_0$, the immune-freeequilibrium is globally asymptotically stable, and the HTLV-I infection is chronic but with nopersistent CTL response. If $1 < R_1$, a unique HAM/TSP equilibrium exists, and the HTLV-Iinfection becomes chronic with a persistent CTL response. Moreover, we show that the immunedelay can destabilize the HAM/TSP equilibrium, leading to Hopf bifurcations. Our numericalsimulations suggest that if $1 < R_1$, an increase of the intracellular delay may stabilize theHAM/TSP equilibrium while the immune delay can destabilize it. If both delays increase, thestability of the HAM/TSP equilibrium may generate rich dynamics combining the ``stabilizing"effects from the intracellular delay with those ``destabilizing" influences from immune delay.
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spelling doaj-art-4e1098ccd7de4db6a65d7576b4a836c52025-01-24T02:31:53ZengAIMS PressMathematical Biosciences and Engineering1551-00182014-12-0112343144910.3934/mbe.2015.12.431A mathematical model of HTLV-I infection with two time delaysXuejuan Lu0Lulu Hui1Shengqiang Liu2Jia Li3Academy of Fundamental and Interdisciplinary Science, Harbin Institute of Technology, 3041#, 2 Yi-Kuang street, Harbin, 150080Academy of Fundamental and Interdisciplinary Science, Harbin Institute of Technology, 3041#, 2 Yi-Kuang street, Harbin, 150080Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, 3041#, 2 Yi-Kuang Street, Harbin, 150080Department of Mathematical Sciences, University of Alabama in Huntsville, Huntsville, AL 35899In this paper, we include two time delays in a mathematical model for the CD8$^+$ cytotoxicT lymphocytes (CTLs) response to the Human T-cell leukaemia virus type I (HTLV-I) infection,where one is the intracellular infection delay and the other is the immune delay to account for aseries of immunological events leading to the CTL response. We show that the global dynamicsof the model system are determined by two threshold values $R_0$, the correspondingreproductive number of a viral infection, and $R_1$, the corresponding reproductive numberof a CTL response, respectively. If $R_0<1$, the infection-free equilibrium is globallyasymptotically stable, and the HTLV-I viruses are cleared. If $R_1 < 1 < R_0$, the immune-freeequilibrium is globally asymptotically stable, and the HTLV-I infection is chronic but with nopersistent CTL response. If $1 < R_1$, a unique HAM/TSP equilibrium exists, and the HTLV-Iinfection becomes chronic with a persistent CTL response. Moreover, we show that the immunedelay can destabilize the HAM/TSP equilibrium, leading to Hopf bifurcations. Our numericalsimulations suggest that if $1 < R_1$, an increase of the intracellular delay may stabilize theHAM/TSP equilibrium while the immune delay can destabilize it. If both delays increase, thestability of the HAM/TSP equilibrium may generate rich dynamics combining the ``stabilizing"effects from the intracellular delay with those ``destabilizing" influences from immune delay.https://www.aimspress.com/article/doi/10.3934/mbe.2015.12.431hopf bifurcation.epidemic thresholdhtlv-i infectionlyapunov functionaltime delay
spellingShingle Xuejuan Lu
Lulu Hui
Shengqiang Liu
Jia Li
A mathematical model of HTLV-I infection with two time delays
Mathematical Biosciences and Engineering
hopf bifurcation.
epidemic threshold
htlv-i infection
lyapunov functional
time delay
title A mathematical model of HTLV-I infection with two time delays
title_full A mathematical model of HTLV-I infection with two time delays
title_fullStr A mathematical model of HTLV-I infection with two time delays
title_full_unstemmed A mathematical model of HTLV-I infection with two time delays
title_short A mathematical model of HTLV-I infection with two time delays
title_sort mathematical model of htlv i infection with two time delays
topic hopf bifurcation.
epidemic threshold
htlv-i infection
lyapunov functional
time delay
url https://www.aimspress.com/article/doi/10.3934/mbe.2015.12.431
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