These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Defective macrophage function in neonates and its impact on unresponsiveness of neonates to polysaccharide antigens.
    Author: Chelvarajan RL, Collins SM, Doubinskaia IE, Goes S, Van Willigen J, Flanagan D, De Villiers WJ, Bryson JS, Bondada S.
    Journal: J Leukoc Biol; 2004 Jun; 75(6):982-94. PubMed ID: 14982942.
    Abstract:
    Neonates do not respond to thymus-independent (TI) antigens (Ag), making them vulnerable to infection with encapsulated bacteria. The antibody (Ab) response of adult and neonatal B cells to TI Ag requires certain cytokines, which are provided by T cells or macrophages (MPhi). Lipopolysaccharide (LPS) failed to induce neonatal MPhi to produce interleukin (IL)-1beta and tumor necrosis factor alpha (TNF-alpha) mRNA and to secrete IL-1beta, IL-12, and TNF-alpha. However, LPS induced neonates to secrete some IL-6 and three- to fivefold more IL-10 than adults. Accordingly, adding adult but not neonatal MPhi could restore the response of purified adult B cells to trinitrophenol (TNP)-LPS, a TI Ag. Increased IL-10 is causally related to decreased IL-1beta and IL-6 production, as IL-10(-/-) neonatal MPhi responded to LPS by secreting more IL-1beta and IL-6 than wild-type (WT) neonatal MPhi. When cultures were supplemented with a neutralizing Ab to IL-10, WT neonatal MPhi secreted increased amounts of IL-6 and allowed neonatal MPhi to promote adult B cells to mount an Ab response against TNP-LPS. Thus, neonates do not respond to TI Ag as a result of the inability of neonatal MPhi to secrete cytokines, such as IL-1beta and IL-6, probably as a result of an excess production of IL-10. This dysregulated cytokine secretion by neonatal MPhi may be a result of a reduction in expression of Toll-like receptor-2 (TLR-2) and TLR-4 and CD14.
    [Abstract] [Full Text] [Related] [New Search]