Effect of mutation on helper T-cells and viral population: A computer simulation model for HIV

A Monte Carlo simulation is proposed to study the dynamics of helper T-cell s (N-H) and viral (N-V) populations in an immune response model relevant to HIV. Cellular states are binary variables and the interactions are describ ed by logical expressions. Viral population shows a nonmonotonic growth bef ore reaching a constant value while helper T-cells grow to a constant after a relaxation/reaction time. Initially, the population of helper cells grow s with time with a power-law, N-H similar to t(B), before reaching the stea dy-state; the growth exponent beta increases systematically (beta similar o r equal to 1-2) with the mutation rate (P-mut similar or equal to 0.1 - 0.4 ). The critical recovery time (t(c)) increases exponentially with the viral mutation, t(c) similar or equal to Ae(alpha Pmut) with alpha = 4.52 +/- 0. 29 in low mutation regime and alpha = 15.21 +/- 1.41 in high mutation regim e. The equilibrium population of helper T-cell declines slowly with P-mut a nd collapses at similar to 0.40; the viral population exhibits a reverse tr end, i.e., a slow increase before the burst around the same mutation regime .