Clara cell 16-kd protein downregulates T(H)2 differentiation of human naive neonatal T cells.
BACKGROUND
Levels of the Clara cell 16-kd protein (CC16) are lower in plasma and bronchoalveolar lavage fluid from adults with asthma relative to those seen in healthy control subjects, and CC16 inhibits the T(H)2 cytokine production from murine T cells.


OBJECTIVE
We sought to determine the plasma levels of CC16 in infants and to investigate whether CC16 might inhibit the T(H)2 cytokine production from neonatal T cells.


METHODS
Cord blood and blood samples at 4, 18, and 36 months of age were taken from 64 children prospectively, and CC16 levels were analyzed in plasma. Cord monocyte-derived dendritic cells (DCs) were pulsed with birch allergen extract alone or together with CC16 or prostaglandin D(2) receptor inhibitors, after which autologous naive CD4(+) T cells were added to the DCs. The production of IL-5, IL-13, and IFN-gamma was measured by means of ELISA and flow cytometry.


RESULTS
The plasma levels of CC16 in children peaked at 4 months. CC16 did not directly affect the cytokine production from human T(H)2 cells. However, CC16 inhibited birch pollen extract-stimulated T(H)2 differentiation of naive T cells through the DC. Inhibition of the prostaglandin D(2) receptors did not consistently result in suppressed T(H)2 differentiation.


CONCLUSIONS
The production of CC16 seems to peak early in life, and CC16 has an inhibitory effect on T(H)2 cell differentiation from human infants by affecting DCs.


CONCLUSIONS
CC16 is an immunoregulatory protein, and its inhibitory effect on T(H)2 cell differentiation might be of importance in the pathogenesis of allergy in infants.
Johansson
Sofi
S
Department of Pediatrics, Sahlgrenska Academy, Göteborg University, Göteborg, Sweden. sofi.johansson@rheuma.gu.se
Wennergren
Göran
G
Aberg
Nils
N
Rudin
Anna
A
D000375:Aging / Q000097:blood; D000485:Allergens / Q000276:immunology; D029662:Betula / Q000737:chemistry; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D002675:Child, Preschool; D016207:Cytokines / Q000096:biosynthesis; D003713:Dendritic Cells / Q000166:cytology / Q000378:metabolism; D005312:Fetal Blood; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018793:Interleukin-13 / Q000037:antagonists & inhibitors / Q000378:metabolism; D015848:Interleukin-5 / Q000037:antagonists & inhibitors; D010936:Plant Extracts / Q000494:pharmacology; D011058:Pollen / Q000737:chemistry; D011971:Receptors, Immunologic / Q000037:antagonists & inhibitors; D011982:Receptors, Prostaglandin / Q000037:antagonists & inhibitors; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000166:cytology* / Q000378:metabolism; D014598:Uteroglobin / Q000097:blood / Q000502:physiology*
D000485:Allergens; D016207:Cytokines; D018793:Interleukin-13; D015848:Interleukin-5; D010936:Plant Extracts; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin; C556389:SCGB1A1 protein, human; C501562:prostanoid D receptor 1, human; D014598:Uteroglobin; C036293:prostaglandin D2 receptor