Adaptive immunity Flashcards
true or false: antigens activate T cells
false - antigen presenting cells do
what are intracellular and extracellular microbes
intracellular = microbes that divide inside cells. they are usually viruses extracellular = microbes which divide outside of cells. these are mainly bacteria
where are antigen presenting cells located
in the skin (SALT), mucus membranes (GALT, BALT), lymph organs and in the blood
how do antigen presenting cells capture the pathogen
by phagocytosis (may require opsonisation) of whole microbes or macropinocytosis of soluble particles
how do antigen presenting cells detect the pathogens
with their PRRs which are specific to the PAMPs on the microbes
name 4 different APC
dendritic cells - found in lymph nodes, mucus membranes and blood and present to naive T cells
langerhans cells -found in the skin and present to naive T cells
Macrophages - found in various tissues and present to effector T cells
B cells - found in lymphoid tissue and present to effector and naive T cells
what are naive T cells
T cells which havent yet been activated by APC
what type of immunity is initiated by extracellular microbes
humoral immunity (involving antibodies, complement and phagocytosis)
what type of immunity is initiated by intracellular microbes
cell dependant immunity (involving cytotoxic t lymphocytes, antibodies and macrophages)
what is required for antigen presentation
major histocompatibility complex
what is MHC
cell surface proteins which recognise and bind to antigens and display them on their surface for recognition by T cells
where are class I and class II MHC molecules found
- found on all nucleated cells (class I)
- found on dendritic, macrophages and B cells (class II)
what genes code for class I MHC molecules
HLA A, HLA B and HLA C
What genes code for class II MHC molecules
HLA DR, HLA DQ, HLA DP
true of false - classes I and II MHC molecules are co-dominant
true - this increases the number of different MHC molecules