Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6371061 | Journal of Theoretical Biology | 2012 | 13 Pages |
We present a new hybrid stochastic-deterministic, spatially distributed computational model to simulate growth competition assays on a relatively immobile monolayer of peripheral blood mononuclear cells (PBMCs), commonly used for determining ex vivo fitness of human immunodeficiency virus type-1 (HIV-1). The novel features of our approach include incorporation of viral diffusion through a deterministic diffusion model while simulating cellular dynamics via a stochastic Markov chain model. The model accounts for multiple infections of target cells, CD4-downregulation, and the delay between the infection of a cell and the production of new virus particles. The minimum threshold level of infection induced by a virus inoculum is determined via a series of dilution experiments, and is used to determine the probability of infection of a susceptible cell as a function of local virus density. We illustrate how this model can be used for estimating the distribution of cells infected by either a single virus type or two competing viruses. Our model captures experimentally observed variation in the fitness difference between two virus strains, and suggests a way to minimize variation and dual infection in experiments.
⺠We simulate growth competition assays used to determine the ex vivo fitness of HIV-1. ⺠Our model accounts for viral diffusion via a deterministic diffusion model. ⺠Cellular dynamics are simulated via a stochastic Markov chain model. ⺠We estimate experimentally a cell's probability of infection based on viral density. ⺠The model captures observed variation in the fitness difference between two viruses.