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A Cellular Automata Model on HIV Infection (2)
Shiwu Zhang
Based on [Pandey et al’s work]
Review: CA models on HIV(1)
• Characteristics– Local interactions
– Inhomogeneous elements
– Spatial structure
– High workload
• Examples– Santos2001
– Hershberg2001
Review: CA models on HIV(1)
– Santos’ CA model• One type cell with 4 different states on one site
• No mutation
• 3-stage evolution: different time scale
– Hershberg’s model in “shape space”• Virtual space, 2 types of cells
• Mutation
• 3-stage evolution: different time scale
Pandey’s model: Introduction(1)
• Elements– 2-dimension or 3-dimension lattice, – Four types of entities:
• Macrophage(M)• Helper(H)• Cytotoxic cells(C)• Antigen/Viral carrier cells(V)
– Entity States: • 0: low concentration • 1: high concentration
Pandey’s model: Introduction(2)• Rules
– Boolean expression(4)
– viral mutation(10)
– Fuzzy set
– CA sum rules
Pandey’s model: Result
• Populations of Cells and virus– Initial immune response
• Influence factors:– Viral mutation rate– Initial concentrations of cells– Cellular mobility
Comparison: our model• Method: Reasonable-> Convincing
– Multi-type elements: T cells, B cells, HIV…
– Spatial space& shape space
– Accounting for important interactions• HIV high mutation rate
• Immune cells stimulation
• Immune system’s global ability:memory
• Result:– 3-stage dynamics of AIDS
– HIV strain diversity
– Mechanism influence
Related Papers• R.B. Pandey. (1998). A stochastic cellular automata approach to
cellular dynamics for HIV: effect of viral mutation. Theory in Bioscience: 117(32)
• H. Mannion et al. (2000). Effect of Mutation on Helper T-cells and Viral Population: A Computer Simulation Model for HIV. Theory in Bioscience: 119(10)
• H. Mannion et al. (2000). A Monte Carlo Approach to Population Dynamics of Cell in an HIV Immune Response Model. Theory in Bioscience: 119(94)
• A. Mielke and R.B. Pandey. (1998). A computer simulation study of cell population in a fuzzy interaction model for mutating HIV. Physica A:251 (430).
• R.B. Pandey et al. (2000). Effect of Cellular Mobility on Immune Response. Physica A:283 (447).