Accumulation of memory T cells from childhood to old age: central and effector memory cells in CD4(+) versus effector memory and terminally differentiated memory cells in CD8(+) compartment.
Memory T cells can be classified as central memory (T(CM), CD45RA(neg)CCR7(+)), effector memory (T(EM), CD45RA(neg)CCR7(neg)), and terminally differentiated cells (T(TD), CD45RA(+)CCR7(neg)) with different homing and effector capacities. In 101 healthy subjects aged from 5 to 96 years, distinct dynamics were evidenced between circulating CD4(+) and CD8(+) T cell populations. Naive CD4(+) and CD8(+) T cells decreased linearly with age, CD8(+) twice more rapidly. Memory cells outnumbered naive cells on average at 37.4 in the CD4(+) and 29.5 years of age in the CD8(+) pool. CD4(+) T(CM) and T(EM) cells were positively correlated and increased linearly at a similar rate with age, while CD4(+) T(TD) remained rare. CD8(+) T(EM) and T(TD) accumulated linearly with age, while T(CM) increased only slightly, and each memory subset was negatively correlated to the two others. Almost all CD8(+) T(TD) and some CD8(+) T(EM) had lost CD28 expression. Despite different dynamics, each individual CD4(+) naive and memory subset was correlated to the synonymous CD8(+) subset. Half of the subjects aged 65 years or older were characterized by extremely reduced CD8(+) naive and increased CD8(+) T(TD) cell counts, which could indicate an acceleration of the decay of the immune system from this age onward.
Saule
Pasquine
P
Laboratoire d'Immunologie, EA 2686, CHU and Université de Lille 2, 59045 Lille, France.
Trauet
Jacques
J
Dutriez
Virginie
V
Lekeux
Véronique
V
Dessaint
Jean-Paul
JP
Labalette
Myriam
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007156:Immunologic Memory; D007223:Infant; D008297:Male; D008875:Middle Aged