[Mathematical model of the age-related changes in peripheral T cells population]

An analysis is presented of the data concerning to the decline with the age the human immune system function. The most prominent changes links with T-cellular immunity. The embrace the naive T cells generation rate diminishing, peripheral lymphoid tissue volume shrinkage, absolute and relative concentration of naive T cells in blood decreasing, average length of T cell telomers reducing. The alterations in immune system led to sharp growth of morbidity and mortality caused by infectious agents. Analysis of the data reveal that key variables of this process are memory and naive T cell concentrations in peripheral lymphoid tissue. The proposed long-time mechanism which hold concentration of T cells in physiological limits are based on assumptions that naive and memory T cells disposed in common niche. The average life-time of memory T cells are varied so that general concentration of T cells holds in normal limits. Numerical experiments demonstrate that average life-time of memory T cells grows with aging, limitation of antigenic load led to considerable grow of resistance in middle age but to little grow in older age. Restriction of thymus involution led to grow of resistance in older age but compensate by diminishing of memory power and longevity.

The proposal model describe the trade-off between naive and memory T cell subpopulations concentrations and proliferative potentials.