Table 2 Parameter settings
From: Understanding the HIV coreceptor switch from a dynamical perspective
parameter | R5 virus | X4 virus |
|---|---|---|
number of strains | n R5 | n X4 |
viral growth rate r i | r (2d-1) | r(1 + αz) ((2 + z)d-1) |
effect of specific immune response p i | p R5 (2d-1) | pX4 >pR5 (20d-1) |
effect of cross-reactive immunity q i | q (1.86d-1) | |
stimulation of specific and cross-reactive immunity c i , k i | c, k (0.1d-1V L-1) | |
natural and virus induced depletion of immune response b, u i | b, u (0.02d-1, 0.1d-1V L-1) | |
probability to generate a new strain p m per day and viral load |
(0.005d-1V L-1) | |
- Parameter settings for R5 and X4 viruses, the values chosen in the simulations are given in brackets in units per day (d) and viral load (VL), due to the close genetic neighbourhood of R5 and X4 viruses it is assumed that both mutants occur with the same probability
from the total viral population irrespective of its composition. Where direct biological interpretation is possible parameters have been chosen following [29, 30], remaining degrees of freedom have been fixed to account for the appropriate dynamical regime defined by equation (4). Note that the growth rate of X4 viruses is assumed to increase proportional to the immune activation measured by the cross reactive immunity z with α = 0.5.