Skip to Main Content




The fetus and neonate are more vulnerable than older children and adults to severe infection with pathogens, including pyogenic bacteria, fungi, viruses, and intracellular protozoa.1 Although this vulnerability indicates substantial limitations in innate and adaptive immunity in prenatal and early postnatal life, the mechanistic basis for these is only partially understood. Hematopoietic stem cell transplantation also provides compelling evidence for impairment of neonatal T-cell and natural killer (NK) cell immunity: Allogeneic hematopoietic cell transplantation with cord blood is associated with a significantly lower risk of acute graft-vs-host disease—a disease that is mainly mediated by donor-derived naïve T cells—compared to bone marrow and peripheral blood transplants containing adult T cells.2




CD11c+ dendritic cells (DCs) are myeloid-derived cells that participate in antigen presentation to T cells and B cells and also produce critical cytokines that shape adaptive immune responses. For example, the cytokines interleukin (IL)-12 p70, a heterodimer of the IL-12/IL-23 p40 subunit and IL-12 p35, and IL-15, which are produced by DCs, not only provide early innate immune protection but also promote the development of an adaptive immune response dominated by T helper 1 (Th1)–type effector CD4 T cells that produce interferon (IFN)-γ. Plasmacytoid dendritic cells (pDCs) are a distinct DC population that, at rest, lacks the characteristic dendrite-like protrusions of CD11c+ DCs and is found in lymphoid tissue, the circulation, and certain sites of tissue inflammation (eg, the skin in herpes simplex virus [HSV] infection). Activated pDCs are an important source of type I IFNs, which include multiple types of IFN-α and a single type of IFN-β. These type I IFNs are an important source of early and systemic innate antiviral immunity and enhance the later adaptive immune response, including Th1 differentiation from naïve CD4 T-cell precursors. DCs are activated by their recognition of conserved structures of microbial pathogens by toll-like receptors (TLRs), C-lectin-type receptors (CLRs), retinoic acid inducible gene-I (RIG-I)-like receptors (RLRs), and nucleotide binding domain and leucine-rich repeat-containing receptors (NLRs)3 as well as other stimuli.


DCs in Tissues


The colonization of CD11c+ DCs in extralymphoid and lymphoid tissues is developmentally regulated and occurs independently of exposure to inflammatory mediators. Immature CD11c+ DC lineage cells are found in the interstitial regions of solid organs, including the kidney, heart, pancreas, and lung, but not the brain, by 12 weeks of gestation; their numbers progressively increase through 21 weeks’ gestation.3 Epidermal DC-like cells that express the human MHC (major histocompatibility complex) class II isotype, HLA-DR (human leukocyte antigen DR), are found in the skin earlier, at 7 weeks’ gestation, and are probably derived from CD45+ HLA-DR+ cells that enter the epidermis, extensively proliferate, and then acquire the characteristic features of Langerhans DCs, including CD1c, langerin, and CD1a in a stepwise manner.4


Circulating and Monocyte-Derived DCs



Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.


Create a Free MyAccess Profile

* Required Fields

Note: If you have registered for a MyAccess profile on any of the Access sites, you can use the same MyAccess login credentials across all sites.

Passwords must be between 6 and 40 characters long (no whitespace), cannot contain characters #, &, and must contain:
  • at least one lowercase letter
  • at least one uppercase letter
  • at least one digit

Benefits of a MyAccess Profile:

  • Remote access to the site off-campus on any device
  • Notification of new content via custom alerts
  • Bookmark your favorite content such as chapters, figures, tables, videos, cases and more
  • Save and download images to PowerPoint
  • Self-Assessment quizzes saved for quick review
  • Custom Curriculum access for both instructors and learners

Subscription Options

AccessPediatrics Full Site: One-Year Subscription

Connect to the full suite of AccessPediatrics content and resources including 20+ textbooks such as Rudolph’s Pediatrics and The Pediatric Practice series, high-quality procedural videos, images, and animations, interactive board review, an integrated pediatric drug database, and more.

$595 USD
Buy Now

Pay Per View: Timed Access to all of AccessPediatrics

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.