Lecture 3 8/30/23 Flashcards
What are the characteristics of dendritic cells?
-most potent antigen-presenting cells
-more powerful than neutrophils and macrophages
-capture, process, and present antigens to adaptive cells
How do dendritic cells kill?
nitric oxide
Why are dendritic cells so crucial to the adaptive immune system?
DCs are the only antigen-processing cells that can activate naïve T cells
Why are dendritic cells said to act as sentinels?
they patrol the mucosal surfaces of the gut and capture foreign antigens from new foods/substances to test
What are the five types of dendritic cell?
-plasmacytoid
-classical type 1
-classical type 2
-follicular
-Langerhans
Which dendritic cells are produced by myeloid precursors?
-classical types 1 and 2
-follicular
-Langerhans
Which dendritic cell is produced by lymphoid precursors?
plasmacytoid
What are the characteristics of Langerhans cells?
-found in the deeper layers of skin
-trap antigens entering through the epidermis
What diseases are Langerhans cells involved in?
-delayed hypersensitivity
-allergic contact dermatitis
What type of pathogen do plasmacytoid and classical type 1 DCs respond to?
viruses
How do plasmacytoid and classical type 1 DCs kill?
interferon
How do Langerhans cells kill?
Birbeck granules/X bodies
What roles do classical type 2 and follicular DCs play?
essential for:
-helper T cell activation
-antibody production
-B cell memory development
What type of infections are classical type 2 and follicular DCs present in?
bacterial and parasitic infections
What substance is secreted by classical type 2 and follicular DCs?
cytokines
Which complement proteins are important for the immune system?
C1 through 9
Which cell type synthesizes the majority of complement proteins?
hepatocytes
Which cell type produces the C2 complement protein?
macrophages
Which cell type produces the C1q complement protein?
mast cells
Which cell type produces the C6 and C7 complement proteins?
neutrophils
What is the membrane attack complex?
a pore created when complement proteins bind on the surface of bacteria with additional proteins
What is the importance of the membrane attack complex?
-pore allows fluid to rush into the bacteria
-bacterial cell lysis and death occur as a result
What are the three activation pathways for complement?
-innate
-alternate
-classical
When is the innate pathway triggered?
when mannose-binding lectin (MBL) binds directly to a microbe
Which microbes trigger the innate pathway?
-Salmonella
-Candida
When is the alternate pathway triggered?
when the C3b protein directly binds a micrboe
Which microbes trigger the alternate pathway?
-Clostridium
-Staphylococcus
Which complement activation pathway requires the adaptive immune system?
classical
When is the classical pathway triggered?
when antibodies are secreted by plasma cells
What happens once the complement system is activated?
it produces peptides that attract other innate immune cells
Which immune cell type is attracted by C3a?
eosinophils
Which immune cell types are attracted by C5a?
-neutrophils
-eosinophils
-macrophages
Which immune cell types are attracted by C567?
-neutrophils
-eosinophils
Which immune cell type is attracted by FBb?
neutrophils
What is promoted by C3e?
leukocytosis
