Immunology 1: Lymphoid Cells/Tissue Flashcards
What is plasma?
the components of blood after red and white blood cells have been removed; contains clotting factors, antibodies, complement proteins, etc.
What is serum?
the components of blood that are neither cells nor clotting factors
What is a titer?
the measurement of the concentration of a substance in a solution; most typically refers to the concentration of antibodies specific for a particular antigen
What does the suffix -penia mean?
deficiency, or a lack of
What are bands?
immature neutrophils that are observed during bacterial infections
What are the recognition mechanisms of the innate immune system? (re: onset, response type, number of specificities, activity over time)
rapid response (hours); fixed specificities; limited number of specificities; constant response during course of infection; same reponse for each encounter with a specific pathogen
What are the recognition mechanisms of the adaptive immune system? (re: onset, response type, number of specificities, activity over time)
slow response (days to weeks); variable response; lymphocytes have numerous highly selective specificities; improves during response; involves clonal expansion and memory of response for increased effectiveness in future encounters
What are pattern recognition receptors (PRRs)?
receptors expressed on the surfaces of innate immune cells that recognize pathogen-associated molecular patterns (PAMPs); this concept is the reason for limited specificities of the innate immune response
How do cells of the acquired immune system have numerous specificities?
the B and T cells express highly specific receptors that recognize specific structures of a particular pathogen
What are the three broad categories of the non-cellular innate immune response?
mechanical/chemical; microbiological; complement cascades
Name examples of innate immunity mechanical barriers.
epithelial cells joined by tight junctions; longitudinal flow of air/fluid; movement of mucus by cilia
Name examples of innate immunity chemical barriers.
fatty acids; low pH; enzymes; saliva; defensins (antibacterial peptides)
Name examples of innate immunity microbiological barriers.
normal flora of skin, GI tract, respiratory tract, UG tract, eyes
When the complement cascade is initiated, there are three end products that help to control or eliminate infectious agents. They are:
- anaphylotoxins: inflammatory mediators
- opsonins: mark pathogens for uptake & destruction by neutrophils/macrophages
- membrane attack complex: inserts into bacterial outer envelopes to perforate/kill pathogenic cells
What are the three broad categories of the cellular innate immune response?
immune cells
What are the primary lymphoid tissues?
bone marrow and thymus
In what tissue/organ are all acquired immune responses initiated?
secondary lymphoid tissue, such as spleen, Peyer’s patches, lymph nodes, tonsils, and mucosa-associated lymphoid tissue (MALT)
What are the functions of erythrocytes?
- transport of oxygen to all cells in the body
2. clearance of immune complexes from circulation
What are the functions of megakaryocytes?
produce platelets, or thrombocytes
What are the functions of bands?
during bacterial infections they move in large numbers to take up and kill bacteria
What are the functions of neutrophils?
- recognize pathogens by their PRRs
2. control bacterial and fungal infections
What is a monocyte?
monocytes are circulating precursors to macrophages; they leave the vasculature, move into tissues, and become mature machrophages
What are the innate immune functions of a macrophage?
recognize (by PRRs), engulf, and destroy potential pathogens
What are the acquired immune functions of a macrophage?
1 of 3 professional antigen presenting cell types that can activate T cells; express antibody Fc receptors that allow it to be bridged into an acquired immune response
What are the functions of eosinophils?
primary role is to control parasite infections; have IgE antibody receptors; contain granules with inflammatory mediators and other compounds that are toxic to parasites
What are the functions of basophils?
primary role is to control parasite infections; appear to function very similarly to eosinophils, otherwise they are poorly characterized cells
What cell types of the innate immune system are considered granulocytes?
neutrophils, bands, eosinophils, basophils
What are the functions of mast cells?
primary role is to control parasite infections; granules contain inflammatory mediators (including histamine); have high affinity IgE receptors on surface
What are the functions of natural killer cells?
innate control of viral infections; bear no antigen-specific receptor therefore are a purely innate cell; identify and kill infected cells to limit the replicating cycle of the pathogen; express Fc receptors, therefore they are the effectors of antibody-dependent cell mediated cytotoxicity (ADCC)
Inflammation is important to the innate control of infections, and it’s critical for the initiation of the adaptive immune response because…
…it promotes movement of antigens and antigen-presenting cells into the nearest secondary lymphoid tissues, where the adaptive immune response can be initiated.
The spleen is a secondary lymphoid tissue important for:
filtering blood for phagocytes to remove pathogens; also for storing new RBCs and removing old RBCs (red pulp)
Lymph nodes are dispersed throughout the body, connected by _____, and capture antigens from _____.
lymphatic vessels; lymph
____ are the most organized tissue of the GALT, or gut-associated lymphoid tissue.
Peyer’s patches
Describe the basic organization of secondary lymphoid tissue, such as that seen in white pulp/Peyer’s patches/lymph nodes.
germinal center within B cell zone, closely associated concentrated T cell zone occupied by antigen presenting cells; T cell interacts more closely with blood in order to recognize the antigen and supply a second signal to activate the B cells
What is the location and function of microfold cells (aka M cells)?
located in Peyer’s patches; role is to sample antigens from gut lumen, transport into patch for antigen presentation to T cells and sampling by B cell receptors
How do antigens and antigen presenting cells get transported from Peyer’s patches to lymph nodes?
via the efferent lymphatics of the Peyer’s patch
What 3 cell types have the role of antigen presentation to T cells?
dendritic cells (innate cell) macrophages (innate cell) B cells (adaptive cell)