Second Line- Immune Cells

What are Macrophages and what is there purpose (2)?

large phagocytes that mature from monocytes in the blood after entering damaged tissues. they engage in phagocytosis to eliminate pathogens and clear debris. they also act as APCs to process foreign antigens and present them on MHC II marker to help activate T helper cells

What are Neutrophils and what is there purpose (2)?

white blood cells that are first responders but are short lived, and undergo programmed cell death after engulfing pathogens, becoming key component of pus. they enter infected tissues to engulf and destroy pathogens via phagocytosis

What are Dendritic cells and what is there purpose?

star shaped cells found in tissues that are incontact with external environment eg. skin cells. they are APCs and engulf pathogens via phagocytosis and migrate through the lymphatic system to the lymph nodes and present the MHC II markers to activate Naive T cells

What are Mast Cells and what is there purpose?

leukocytes in connective tissues concentrates near blood vessels and external barriers. when activated by pathogens they degranulate to release histamine, which causes vasodilation and increases capillary permeability, initiating inflammatory response

What is the purpose of Eosinophils?

they attach to the surface of the parasite and release highly toxic chemical agents from their granules directly onto the pathogen to destroy it externally

What is the purpose of Natural Killer Cells?

they scan the body for MHC I markers and release perforins and granzymes, inducing apoptosis

What are Complement Proteins and what is there purpose?

proteins that circulate in blood plasma until activated where they have three mechanisms. Opsonisation is when activated proteins coat the outer surface of the pathogen to make it easier for phagocytes to bind and engulf the pathogen. Chemotaxis is where small protein fragments diffuse away from infection site to act as a signal for phagocyte. complement proteins gather on membrane of the pathogen to form MAC which punches physical pores in pathogen walls causing cell to burst

What are Interferons and what is there purpose?

a type of cytokine infected by a host cell that has been infected by a virus. they act as a warning to protect surrounding, uninfected cells and halt the spread of virus through the tissue