Med Micro 4.1 - 2nd Line (blood) Flashcards
What makes up second line of defense?
cells, anti microbial chemicals and processes (mostly in blood): phagocytosis, complement, interferon, inflammation, fever. No physical barriers except blood clotting. Most components are not just sitting there but are recruited.
What is the second line for?
When pathogens penetrate skin or mucous membranes (some things like defensins are present on the mucous membranes already). It is non-specific, but lots of communication
Major goals of second line
Containment (as limited as possible), and signal adaptive immunity (induces the 3rd line)
Plasma
Water with electrolytes, gases, nutrients, protein (clotting factors, complement proteins, ABs)
Serum
Name for plasma when coagulation proteins removed
Functions of innate immune system (6)
- Physical and chemical barrier 2. Recruiting immune cells to sites of infections (cytokines) 3. Activate complement cascade to identify bacteria, lyse cells and attract and promote phagocytosis (opsonize bac) 4. Identify and remove of foreigners by WBC 5. Activate inflammation and fever 6. Activate adaptive immune system with antigens etc.
Functions of innate immune system Acronym
BRCA WI: Barrier, Recruit, Complement, Activate Adaptive, WBC, Inflammation
How do we sequester iron? How do bacteria circumvent this?
We have lactoferrin (in tears, mucous). They have siderophores (membrane-bound or secreted) and hemolysin. Siderophores still from hemoglobin with high binding affinity. Lactoferrin binds even tighter. Competition.
Nutrient immunity
a term to describe how we generally sequester nutrients so they are not available
Platelets: Origin and function
from megakaryocytes. Clotting, secrete TGFß and FGF
Leukocytes
aka WBC. 2 types: granulocytes (secrete toxins in granules, and phagocytosis) and agranulocytes (B cell, secrete AB
3 types of granulocytes
Basophils (heparin and histamine, bind IgE ABs, in allergies); eosinophils ; neutrophils
Macrophages
Some fixed (specific names, like dendritic cell), some mobile and phagocytose throughout body. Release cytokines to attract neutrophils and signals for tissue repair
Neutrophils
lactoferrin, defensins, other chems; Phagocytize pathogens, Capable of diapedesis
Eosinophils
cationic proteins, reactive O2 species; Phagocytize pathogens, Capable of diapedesis
Diaspedesis
can squeeze out of blood vessels to enter an area. (in veins, not out of arteries). Bind to sites on vessels before squeezing out