Immune system development during early childhood in tropical Latin America: evidence for the age-dependent down regulation of the innate immune response.
The immune response that develops in early childhood underlies the development of inflammatory diseases such as asthma and there are few data from tropical Latin America (LA). This study investigated the effects of age on the development of immunity during the first 5 years of life by comparing innate and adaptive immune responses in Ecuadorian children aged 6-9 months, 22-26 months, and 48-60 months. Percentages of naïve CD4+ T cells declined with age while those of memory CD4(+) and CD8(+) T cells increased indicating active development of the immune system throughout the first five years. Young infants had greater innate immune responses to TLR agonists compared to older children while regulatory responses including SEB-induced IL-10 and percentages of FoxP3(+) T-regulatory cells decreased with age. Enhanced innate immunity in early life may be important for host defense against pathogens but may increase the risk of immunopathology.
Laboratorio de Investigaciones FEPIS, Quininde, Esmeraldas Province, Ecuador. rommynateran@gmail.com
Rommy
R
Teran
Edward
E
Mitre
Maritza
M
Vaca
Silvia
S
Erazo
Gisela
G
Oviedo
Marc P
MP
Hübner
Martha E
ME
Chico
Joseph J
JJ
Mattapallil
Quentin
Q
Bickle
Laura C
LC
Rodrigues
Philip J
PJ
Cooper
D056704:Adaptive Immunity; D000367:Age Factors; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002657:Child Development; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D015536:Down-Regulation / Q000276:immunology*; D004484:Ecuador; D005260:Female; D006801:Humans; D007107:Immune System / Q000254:growth & development*; D007113:Immunity, Innate; D007223:Infant; D016753:Interleukin-10 / Q000276:immunology; D018655:Lymphocyte Count; D008297:Male; D051193:Toll-Like Receptors / Q000819:agonists / Q000276:immunology
D051193:Toll-Like Receptors; D016753:Interleukin-10
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