3 - Cells and Organs of The Immune System Flashcards
Where do all immune cells come from? (what cells?)
hematopoietic stem cells (HSC)
Which organ do hematopoietic stem cells come from?
bone marrow
What does the term “leukocytes” mean?
differentiated cells from HSC that contain a nucleus
When do red blood cells (RBCs) lose their nucleus?
when they leave the bone marrow and develop
What is the difference in cases when adults have nucleated RBCs in their blood as opposed to when infants do?
in adults = abnormal = indicates something is wrong | in infants = normal
What are megakaryocytes?
platelets
What are granulocytes?
immune cells with granules present
What are the 3 granulocytes?
neutrophils, basophils, eosinophils
What are neutrophils also called?
poly-morpho nuclei (PMN)
What cells have multi-lobed nuclei and what does “multi-lobed nuclei” mean?
granulocytes | nucleus is not just one lobe, it has more than 1 (ex: bi-lobe)
What is a high neutrophil count in the circulation indicate?
indicates bacterial infection
What are the 2 major types of progenitor cells?
common myeloid progenitor (CMP) and common lymphoid progenitor (CLP)
Which progenitor cell gives rise to dendritic cells?
both CMP and CLP`
Out of all of the blood cells, which cells last for days to years? (long time)
lymphocytes
Which white blood cells last for the shortest time?
neutrophils (6-48 hours)
What is the function of neutrophils?
leave circulation »_space;> go to infected tissue »_space;> blow themselves up to cause direct harm to pathogen
What do basophils indicate? What do they stain with?
allergic infection and inflammation | basic dye
What do eosinophils indicate? What do they stain with?
commonly allergic reactions | also viral and parasitic infections | acidic dye = red granules
What is the purpose of granules?
contains toxic proteins that kills off pathogens once the pathogens come into contact with the toxic proteins
What do histamines do and induce?
vasodilation to get more blood cells into circulation to help fight off infection | induce inflammatory proteins
What does pus formation indicate?
dead neutrophils in tissue
What are mast cells?
basophils in tissue
What occurs when mast cells degranulate?
secretes all of the proteins stuck in them
Are all granulocytes phagocytic?
yes
What is the function of elastin and collagenase?
tissue remodeling
What are 2 characteristics of monocytes?
larger than lymphocytes and granulocytes | big un-lobed round nucleus
What are monocytes in the tissue called?
macrophages
What are 2 things that monocytes can become?
macrophages and dendritic cells
What are the 3 functions of macrophages?
help with tissue remodeling | clean up dead neutrophils | help destroy pathogens
What are 4 characteristics of macrophages?
different sizes | lot of pseudopodia | large nucleus and stays in tissue
What connects the innate and adaptive immune response systems?
dendritic cells as well as other PCs
What do dendritic cells act as?
phagocytes
How do dendritic cells help activate T-cells?
eat pathogen »_space;> process it »_space;> present part of it on its surface
Where do dendritic cells stay?
in tissue
What are antigen presenting cells (APCs)?
present pathogen peptides to T-cells
What are the 3 APCs and which one is most potent for activating naiive T-cells?
Dendritic cells (most potent in activating naiive T-cells) | macrophages | B-cells
What does MHC stand for?
major histocompatibility complex
When do dendritic cells mature?
when they have eaten a pathogen
What will dendritic cells do once they mature?
migrate out of the tissues into the lymphatic system to the lymph node where it will come into contact with T-cells
What are the 3 major activities of APCs when they encounter pathogens?
secrete proteins = attract and activate other immune cells | eat pathogens, digest into peptides, present on their MHC class II molecules | express costimulatory molecules to activate T-cells
What are the proteins that APCs produce?
cytokines and chemokines
Which cells ONLY present MHC class II molecules?
APCs
What are CD markers?
clusters of differentiation
What are 2 characteristics of lymphocytes?
smooth nucleus, little cytoplasm (looks similar to monocytes)
How will one be able to differentiate between B and T lymphocytes and innate lymphoid cells (ILCs)?
via Fluorescence-Activated Cell Sorting (FACS)
What are the functions of cytokines?
activates, modulates, regulates other immune cells
What is the function of chemokines? How do they carry out their function?
recruiting other immune cells via chemotactic proteins
What do T-cells express?
CD4 and CD8
What are T-helper (Th) cells?
helps immune response by activating or stimulating other immune cells such as B-cells
What are T-cytotoxic (Tc) cells?
induces lysis
Which T-cell expresses CD4?
T-helper cells
Which T-cell expresses CD8?
T-cytotoxic cells
Where do T-cells mature? (what organ)
thymus
What does a cell expressing a CD3 marker on its surface indicate? What does it induce?
identifies that it is a positive (it expresses it) T-cell receptor | causes signal transduction to occur
Where do B-cells mature?
bone marrow
What is the receptor of B-cells?
immunoglobulins (antibodies)
What does “cognate” mean?
specific/respective
How do lymphocytes become effector lymphocytes?
lymphocyte leaves BM (B-cell) or thymus (T-cell) »_space;> contact with cognate antigen »_space;> becomes actived as effector lymphocyte
What are plasma cells?
effector B-cells with Golgi and ER expanded since the cell has become an antibody-producing machine once activated
What are natural killer (NK) cells part of: CLP or CMP?
CLP
What recognizes virally infected cells?
NK cells
What do B-cell receptors detect?
soluble antigen
What do T-cell receptors detect?
peptide on MHC molecules
Which receptor on T-cells bind to the MHC molecules?
CD4 and CD8
Which MHC class molecule associates with Th cells?
MHC class II
Which MHC class molecule associates with Tc cells?
MHC class I
Which cells do Th cells only interact with and why?
APCs since they are the cells that only express MHC class II molecules which is what Th cells recognize
Which cells express MHC class I?
all leukocytes (not RBCs)
What cell in the BM that create the microenvironment to help B-cells mature into what they need to be?
stromal cells
When do T-cells become either Th or Tc?
when they mature in the thymus
How do the receptors interact between a T-cell and APC?
CD4 or 8 binds to MHC | T-cell receptor then recognizes the peptide as a result of that binding
What are the costimulatory receptors on T-cells?
CD markers such as CD4 and CD8
What does the term “left shift” refer to?
immature neutrophils (PMNs)
Are there more of left shift or PMNs in circulation?
left shift
What does the term “band” refer to?
nucleus has not fully become lobed/multi-lobed = looks like a band
What is thymocyte?
immature T-cell
What aspect of the T-cell is checked in the thymus?
affinity of the T-cell receptor
What are the 2 primary lymphoid organs?
bone marrow and thymus
What are the 3 secondary lymphoid organs?
lymph nodes | spleen | mucosal-associated lymphoid tissue (MALT)
What are the 4 things that secondary lymphoid organs have an effect on lymphocytes?
act as area where lymphocytes: encounter antigens | become activated | clonal expansion | differentiate into effector cells
What is the function of the lymph node?
checks lymphatic system for antigens and pathogens
What is the function of the germinal centers in the lymph nodes?
B-cell undergoes second maturation
Can one survive without a spleen? If so, what/are there any consequences?
yes but will be immunocompromised
Where are the APCs found in the spleen?
marginal zone
Where are the T-cells found in the spleen?
PALS (near marginal zone)
What are Peyer’s patches?
immune centers in the gut = GALT (part of MALT)
What are 3 other MALTs?
gut (GALT) | nasal (NALT) | bronchial (BALT)
