The CpG PAMP is recognized by the pattern recognition receptor (PRR) Toll-Like Receptor 9 (TLR9), which is constitutively expressed only in B cells and plasmacytoid dendritic cells (pDCs) in humans and other higher primates.
The trachea is an important structure within your respiratory system, which is the organ system that delivers oxygen to your bloodstream. The trachea is a rigid tube that conducts air from your larynx to your bronchi. The trachea's rigidity is maintained by a series of cartilaginous rings arranged along its length called C-shaped cartilage rings.
What is the Trachea (Windpipe) Trachea is the medical name for the windpipe, the largest airway in the respiratory system, about 4-5 inches in length and 1 inch in diameter that extends from the lower end of the larynx or voice box [1]. An integral part of the human airway, the trachea, bronchi, bronchioles, and alveoli together make up the lower respiratory tract [2, 3].