Immune Response to a Variable Pathogen: A Stochastic Model with Two Interlocked Darwinian Entities

Figure 10

Computer result of a pathogen 𝑃 (with antigen 𝐴) coupled through averages to an immune system consisting of an effector 𝐸 (producing antigen receptor 𝑎) and memory 𝑀. Case where the pathogen is reappearing while the immune system response is low. Glimpse at generation 𝑛=100. Parameter values other than Figure 2: For average 𝐸>𝑇_𝐸=1.5 (above threshold value, immune effector 𝐸 active): 𝛽_𝑃=0.75. For average 𝑃<𝑇_𝑃=1.5 (below threshold value, pathogen 𝑃 not seen by immune system): 𝛽_𝐸=0.85. For average 𝑃>𝑇_𝑃=1.5 (above threshold value, pathogen 𝑃 seen by immune system): 𝛽_𝐸=0.90.