Microbiology 1010 – Lecture Notes
Leukocytes (white blood cells)
Cells that circulate in the blood and lymph, and reside in lymphoid organs
Involved in both branches of the immune response (innate and adaptive)
o Cytoplasm contains granules filled with reactive chemicals
Can kill microbes
Signal other components of immunity
o 3 Types.
Prefix “A” = means without
Have granulates what have
They create proteins that get sent to get tell the parts of
the body to come to the certain area of the body (signal)
BEN = acronym for granulocytes
24.1 Leukocytes: Granulocytes
Basophils and mast cells – granules stain with basic dyes
Circulate in blood (basophils) or reside in
mucosal tissue (mast cells)
Can be triggered to degranulate
Release vasoactive mediators
o Trigger inflammation
o Ex. Histamine – involved in the allergic response.
Inside the granules contain histamine= vasodilation and is a respirator inhibitor
They limit inflammation in the body – histamine is helpful in normal blood vessel properties
Eosinophils – granules stain with acidic dyes
Can leave the blood and enter tissues in areas of inflammation
Attack large parasites:
Protozoa and parasitic worms
Release reactive oxygen intermediates:
O 2-, 2O 2, OH•
o Destroy parasite from the outside.
Spit digestive enzymes on the organism and you break it down extracellular and then the extra pieces
is used for our own body.
115 Microbiology 1010 – Lecture Notes
Neutrophils – granules are filled with digestive enzymes:
Circulate in blood and migrate to infection sites
Highly phagocytic – “eat” invading bacteria
Central component of innate immunity.
60% of WBC are neutrophils
When the tissue is infectioned.. Vasodilation happens to the vessels get better and the cells spread
out so there is more space for the neurtrophils leave the blood stream along with fluid to the site of
the infection. This is why when we get a cut or infection.. There is edema / swelling happening.
Monocytes – circulate in the blood, and then migrate into tissues and differentiate
into macrophages and dendritic cells
Strongly phagocytic cells involved in antigen presentation
Reside in tissues – lungs, liver, spleen, connective tissues
Specific surface molecules recognize pathogens – Toll-like receptors:
o LPS, peptidoglycan, fungal cell walls etc.
Dendritic cells – Reside in tissues that serve as common entry points for pathogens
Skin – “Langerhan’s cells”