HUBS 191 immunology Flashcards
what is the immune system ?
An organised system of organs cells and molecules that interact together to defend the body against disease
what are the organs involved in the immune system
tonsils thymus spleen bone marrow lymph nodes
primary lymphoid organs
thymus and the bone marrow
secondary lymphoid organs
spleen and the lymph nodes
what are the three immune system defences?
chemical & physical barriers
innate
adaptive
what makes up the chemical and physical barriers of the immune defence system?
the skin & the mucus membranes in skin
innate
- already in place
- rapid
- fixed
- limited specificities
- has no specific memory
adaptive
- improves during the reponse
- slow
- varialbe
- highly specific
- has long term specific memory
innate defenses
skin and mucous membrane and phagocytes, natrual killer cells, inflammation
adaptive defenses
T and B cells
three blood cells
Erthroid
myeloid
lymphoid
Granulocytes in the blood
apart of the myeloid blood cells. Neutrophil are 75% leukocytes which are highly phagocytic
Granulocytes in tissue
mast cells which line the mucous surfaces which release granulates that attract blood cells to the damaged tissue site
Monocytes
when found in the blood they have a low phagocytosis. when they leave the blood to the tissue they become macrophages which have a high phagocytosis.
dendrite cells
are phagocytic and help tigger the adaptive
lymph
white blood cells
PAMPs
pathogen associated molecular patterns
viruses
have a -envelope -nucleocapsid -nucleic acid -ssRNA, dsRNA 'the lose their envelope and neucleocapsid'
bacterium
have a
- capsule
- cell wall
- cell membrane
- nucleic acid - DNA, CpG
- flagella
what are the three complement cascades
opsonisation-label C3b
chemotaxis-recruit C3a & C5a
lysis-destroy C9
complement pathways
classical- antibody bound to pathogen binds complement
alternative- pathogen binds complement to surface/pathogen component
lectin- carbohydrate components of microbes bind complement
antigen
anything that has the potential to be recognised by the immune system
MHC-1
endogenous ‘intracellular’
antigenic Proteins, degraded to peptides in cytoplasm.
than imported to ER.
peptide loading of MHC-1 takes place in ER
MHC-2
exogenous
antigenic proteins degraded in acidic phaglsosomes.
peptide loading of MHC-2 happens in phagolysosome
APC
Antigen Presenting Cells
- cells that link the innate with the t & b cells.
- APC turns pathogen proteins into antigens, they are than presented to the MHC.
- the best APC is DC
T cell
Are lymphocytes, that are specific for a certain protein.
- make Cytokines & Cytotoxic molecules.
can either help or deastroy
-two types CD4 & CD8
Where are T cells made
they are lymphocytes that can from the bone marrow and develop ‘rearrange’ in the thymus.
TCR
T cell receptor.
T cells express TCR with each having a unique TCR for one antigen peptide.
CD4
recognise antigen peptides in context of MHC-2.
they make Cytokines that support other immune cells
CD8
recognise antigen peptides in context of MHC-1.
they make cytotoxic molecules that kill infected cells
cytotoxic T lymphocytes CTL
Naive T cells
are T cells that have not been activated by MHC/peptide
activated T cell
also known as effector T cells
- kill infected cells
- make cytokines
- support antibody production “ B Cells”
- remeber the antigen the next time
Memory T cells
T cell activation can result in memory T cells.
CD4 & CD 8 T cells become effectors much faster than naive T cells
immune response 7 steps
- pathogens infect at tissue site
- DC live in tissue, are the first to see pathogens.
- DC process pathogens into antigenic peptides & load them onto MHC
- DC with antigenic peptides travel to lymph node
- T cells in lymph node meet DC
- T cells become activated in lymph node and become either cytokines or cytotoxic
- B cells in lymph node are activated and make antibodies
inflammatory response 5 steps
- chemical signals from tissue resident cells”mast cells” act to attract more cells “neutrophils” to site of injury or infection
- Neutrophils enter blood from bone marrow
- Neutrophils cling to capillary wall
- chemical signals from tissue make capillary leaky
- neutrophils leave blood to site of injury
