Antigenic distance and cross-immunity, invasibility and coexistence of pathogen strains in an epidemiological model with discrete antigenic space

作者：Adams Ben^*; Sasaki Akira

来源：Theoretical Population Biology, 2009, 76(3): 157-167.

DOI：10.1016/j.tpb.2009.06.001

• Pathogen
• Immunity
• Antigen
• Evolution
• Mathematical model
• Influenza

In models of pathogen interaction and evolution discrete genotypes in the form of bit strings may be mapped to points in a discrete phenotype space based on similarity in antigenic structure. Cross-immunity between strains. that is the reduction in Susceptibility to strain A conferred to a host by infection with strain B, call then be defined for pairs of points in the antigenic space by a specified function Analysis of an SIR type model shows that, if two strains are at equilibrium, the shape of the cross-immunity function has a strong influence on the invasion and coexistence of a third strain and, consequently, the expected evolutionary pathway. A function that is constant except for discontinuities at the end points is expected to result in the accumulation of diversity until a pair of discordant strains occurs that call, depending on parameter values, exclude all other strains. For a function of the form f (h) = h(q), where h is the antigenic distance between two strains, invasion and coexistence is always possible if q <= 1 arid little antigenic structure is expected in the pathogen population. However, if q > 1 invasion arid coexistence may be impossible, depending on parameter values, and the pathogen population is expected to show significant antigenic structuring In addition to illuminating the role of cross-immunity in pathogen evolution, this analysis indicates that the choice of cross-immunity function, the representation of immunity acquired from multiple previous infections arid the number of elements used to characte

• 出版日期2009-11
• 单位国际应用系统分析学会(IIASA)