Dynamics of virus infection under the influence of antibody and cytokine.

To study the macroscopic dynamics of susceptible host cells, infected host cells, free virus particles and antibodies after viral infection within-host, this study develops a novel dynamic model that integrates three key mechanisms: a general incidence function capturing the complexity of antibody production, the inhibitory effect of antibodies on viral infectivity and the cytokine-mediated self-cure of infected cells. The basic reproduction numbers for both the virus and immune response are derived, along with sufficient conditions for the stability of equilibria. Bifurcation analysis revealed that a Hopf bifurcation may occur when the basic reproduction number of the immune response exceeds one. Numerical simulations highlight the critical role of saturation effects in viral replication and the immune response for infection control. Antibody immunity, once depleted, may not be replenished and neglecting saturation effects could overestimate both the oscillatory parameter range and the severity of infection.