Co-dynamics of hepatitis B and C viruses under the influence of CTL immunity

Understanding the cytotoxic T lymphocyte (CTL) immune response against hepatitis B virus (HBV) and hepatitis C virus (HCV) infections is crucial, as these infections can lead to liver cirrhosis and cancer. Mathematical models provide valuable support for biological and medical research by helping to...

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Main Authors: A.M. Elaiw, GH.S. Alsaadi, A.A. Raezah, A.D. Hobiny
Format: Article
Language:English
Published: Elsevier 2025-04-01
Series:Alexandria Engineering Journal
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Online Access:http://www.sciencedirect.com/science/article/pii/S1110016825000560
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author A.M. Elaiw
GH.S. Alsaadi
A.A. Raezah
A.D. Hobiny
author_facet A.M. Elaiw
GH.S. Alsaadi
A.A. Raezah
A.D. Hobiny
author_sort A.M. Elaiw
collection DOAJ
description Understanding the cytotoxic T lymphocyte (CTL) immune response against hepatitis B virus (HBV) and hepatitis C virus (HCV) infections is crucial, as these infections can lead to liver cirrhosis and cancer. Mathematical models provide valuable support for biological and medical research by helping to understand the within-host dynamics of single or multiple viral infections and by aiding the development of effective drug therapies. This study aims to develop an HBV and HCV co-infection model to investigate the role of CTL immunity in combating both viruses. The model incorporates latently and actively infected hepatocytes, multiple distributed-time delays, and a saturated incidence function. To confirm the model’s well-posedness, we demonstrate that its solution remains non-negative and ultimately bounded. The model’s long-term behavior is analyzed by identifying nine equilibrium points and deriving conditions for their existence and stability. These conditions are determined based on key threshold parameters that govern system dynamics. The global stability of all equilibria is proven using Lyapunov’s method combined with LaSalle’s invariance principle. The theoretical findings are further supported and validated through numerical simulations. A sensitivity analysis is conducted to identify the parameter with the greatest influence on model behavior. Additionally, we examine the effects of antiviral therapy, time delays, and CTL immunity. The results indicate that both the length of the delay period and the efficacy of antiviral drugs independently contribute to reducing HBV and HCV levels, thereby improving liver health. Moreover, enhancing the activation rates of CTL immunity increases the population of uninfected hepatocytes and further suppresses viral replication during co-infection. This suggests that certain treatments could be developed to extend the delay period. Additionally, the study underscores the significance of immunotherapy in enhancing the immune system’s response. By stimulating the immune system to function more effectively, immunotherapy can play a vital role in combating viral infections. Effective treatment of infected individuals is crucial in limiting the spread of infectious diseases.
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spelling doaj-art-5d4a0c868ba642189b40f36f2cbe212d2025-02-07T04:47:12ZengElsevierAlexandria Engineering Journal1110-01682025-04-01119285325Co-dynamics of hepatitis B and C viruses under the influence of CTL immunityA.M. Elaiw0GH.S. Alsaadi1A.A. Raezah2A.D. Hobiny3Department of Mathematics, Faculty of Science, King Abdulaziz, P.O. Box 80203, Jeddah 21589, Saudi ArabiaDepartment of Mathematics, Faculty of Science, King Abdulaziz, P.O. Box 80203, Jeddah 21589, Saudi ArabiaDepartment of Mathematics, Faculty of Science, King Khalid University, Abha 62529, Saudi Arabia; Corresponding author.Department of Mathematics, Faculty of Science, King Abdulaziz, P.O. Box 80203, Jeddah 21589, Saudi ArabiaUnderstanding the cytotoxic T lymphocyte (CTL) immune response against hepatitis B virus (HBV) and hepatitis C virus (HCV) infections is crucial, as these infections can lead to liver cirrhosis and cancer. Mathematical models provide valuable support for biological and medical research by helping to understand the within-host dynamics of single or multiple viral infections and by aiding the development of effective drug therapies. This study aims to develop an HBV and HCV co-infection model to investigate the role of CTL immunity in combating both viruses. The model incorporates latently and actively infected hepatocytes, multiple distributed-time delays, and a saturated incidence function. To confirm the model’s well-posedness, we demonstrate that its solution remains non-negative and ultimately bounded. The model’s long-term behavior is analyzed by identifying nine equilibrium points and deriving conditions for their existence and stability. These conditions are determined based on key threshold parameters that govern system dynamics. The global stability of all equilibria is proven using Lyapunov’s method combined with LaSalle’s invariance principle. The theoretical findings are further supported and validated through numerical simulations. A sensitivity analysis is conducted to identify the parameter with the greatest influence on model behavior. Additionally, we examine the effects of antiviral therapy, time delays, and CTL immunity. The results indicate that both the length of the delay period and the efficacy of antiviral drugs independently contribute to reducing HBV and HCV levels, thereby improving liver health. Moreover, enhancing the activation rates of CTL immunity increases the population of uninfected hepatocytes and further suppresses viral replication during co-infection. This suggests that certain treatments could be developed to extend the delay period. Additionally, the study underscores the significance of immunotherapy in enhancing the immune system’s response. By stimulating the immune system to function more effectively, immunotherapy can play a vital role in combating viral infections. Effective treatment of infected individuals is crucial in limiting the spread of infectious diseases.http://www.sciencedirect.com/science/article/pii/S1110016825000560HBV and HCV co-infectionCTL immunityTime delayGlobal stabilityLyapunov function
spellingShingle A.M. Elaiw
GH.S. Alsaadi
A.A. Raezah
A.D. Hobiny
Co-dynamics of hepatitis B and C viruses under the influence of CTL immunity
Alexandria Engineering Journal
HBV and HCV co-infection
CTL immunity
Time delay
Global stability
Lyapunov function
title Co-dynamics of hepatitis B and C viruses under the influence of CTL immunity
title_full Co-dynamics of hepatitis B and C viruses under the influence of CTL immunity
title_fullStr Co-dynamics of hepatitis B and C viruses under the influence of CTL immunity
title_full_unstemmed Co-dynamics of hepatitis B and C viruses under the influence of CTL immunity
title_short Co-dynamics of hepatitis B and C viruses under the influence of CTL immunity
title_sort co dynamics of hepatitis b and c viruses under the influence of ctl immunity
topic HBV and HCV co-infection
CTL immunity
Time delay
Global stability
Lyapunov function
url http://www.sciencedirect.com/science/article/pii/S1110016825000560
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