Table 5. HIV co-infection.

The within-host layer of HIV multi-scale model illustrates the impact of co-infection. This model includes the uninfected and infected target CD4+ T cells, and free virions. Co-infection increases immune response and the infection rate of immune cells. Therefore, the set-point viral load is higher compared to the case of no co-infection.

Model diagram
Equations
$\frac{dT}{d\tau }=\lambda -kTV-dT+\left[1-\frac{T_m+T+T^{\ast }}{T_{max}}\right]r_{T}T$
$\frac{d{T}^{\ast }}{d\tau }=kTV-\left(\mu +d\right)T^{\ast }+k_{Tm}V{T}_m$
$\frac{dV}{d\tau }=N\left(\mu +d\right)T^{\ast }-cV$
Parameters
λ	Reproduction rate of uninfected cells
k	Infection rate of uninfected cells
d	Natural death rate of uninfected cells
μ	HIV induced death rate of infected cells
N	HIV production by infected cells
c	HIV clearance rate
Tm	Activated immune cells against co-infection
Tmax	Maximum number of immune cells
rT	Growth rate of non-specific immune cells
kTm	Infection rate of co-infection