ImmunoSero Lecture (Immune System) Flashcards
Embryonic blood cells, excluding your lymphocytes, originates from the ________________ which is from the embryonic germ layer which is the ____________.
mesenchymal tissue; mesoderm
Where the first blood cells (primitive RBCs; erythroblasts) are formed during the first 2 to 8 weeks of life.
Islets of the yolk sac
Replaces the yolk sac as the site of blood cell development
Liver and Spleen
The major site of hematopoiesis by the second month of gestation where granular types of leukocytes initially appear
Liver
During hematopoiesis, these predominate from about 2 to 5 months of fetal life.
Liver and Spleen
In the fourth month, this begins to produce blood cells and in the fifth month, it assumes its role as the primary site of hematopoiesis
Bone marrow
At the start of postnatal, all of the bones participate in the hematopoietic development, but as we age, it has become more confined in ____________.
Flat bones
(vertebrae, sternum, ribs)
The cellular elements of the blood are produced from …
Multipotential hematopoietic stem cell (Hemacytoblast) CD34 & CD45
Major cellular elements of the circulating blood.
Erythrocytes (RBCs)
Thrombocytes; and
Specific types of Leukocytes (WBCs)
Primary lymphoid organs
Bone Marrow
Thymus
Where all lymphocytes arise from that resides in one of the primary lymphoid organs which is in the bone marrow
Pluripotential hematopoietic stem cells
Among the primary lymphoid organs which is solely dedicated to the T-cell.
Thymus
Known to be the center of antigenic independent lymphopoiesis or in other words the center for the development of your lymphocyte that does not require antigen stimulation.
Bone marrow
The main site for the maturation of your B cells in the peripheral blood.
Bone marrow
Approximately, __________% of leukocytes are B cells, __________ % are NK cells, and the rest are T cells.
10 to 20% - B cell leukocytes
22% - NK cells
A butterfly-shaped, small, flat, and bilobed organ found in the thorax or chest cavity that is capable of producing T lymphocytes until at least the 5th or 6th decade of life
Thymus
This is where T-cell maturation and the acquisition of surface antigens occur.
Thymus
Young T cells are first located in the cortex. After 2-8 weeks, they migrate and populate the ________________. Once they mature into T lymphocytes, they are then released.
medulla
True or False.
Each lymphocte spends the least of its life span in solid tissue, entering the circulation periodically to go from one secondary organ to another.
False. It spends most of its life span
Secondary lymphoid organs
< PAT MLS >
Peyer’s patches
Appendix
Tonsils
Mucosal-associated lymphoid tissue
Lymph nodes; and
Spleen
Play a role in antigen dependent lymphopoiesis
Secondary lymphoid organs
The secondary lymphoid tissues are found in these tracts.
Gastrointestinal Tract
Respiratory Tract
Urogenital Tract
These are localized at some of the main ports of entry for foreign organisms
Marcophages and Lymphocytes
A specialized type of malt specifically found in the ileum of the small intestine that responds to pathogens entering the respiratory tract and alimentary tracts, providing potential sites for contact with foreign antigen and increasing the probability of immune response.
Peyer’s patches
Aww, it patches for you kahit di mo deserve! Char
When stimulated by antigen, B cells form …
Geminal center
This pulp comprises approx. 20 percent of the total weight of the spleen and contains the lymphoid tissue.
white pulp
The largest secondary lymphoid organ which is arranged around arterioles in a periarteriolar lymphoid sheath (PALS)
Spleen
The periarteriolar lymphoid sheath (PALS) mainly contains …
T cells
Attached to the sheath are primary follicles which contain ________________ that are not yet stimulated by antigen.
B cells
Traps antigen
Dendritic cells
How many times will an adult’s blood volume pass through the spleen where lymphocytes and macrophages can constantly survey for infectious agents of other foreign matter?
4 times
These are located along lymphatic ducts and serve as central collecting points for lymph fluid from adjacent tissue.
Lymph nodes
Lymph nodes are especially numerous near the …
Joints and where the arms and legs join the body
The lymph fluid flows slowly through these spaces which are lined with macrophages, creating an ideal location for phagocytosis.
sinuses
Consists of antigen-stimulated proliferating B cells.
Secondary follicles
The interior of a secondary follicle where blast transformation of B cells takes place.
Germinal center
Actively secretes antibodies
Plasma cells
Primary function of lymph nodes
Generation of B-cell memory
T lymphocytes are mainly localized in …
the paracortex
antigen-presenting cells
interdigitating cells
Transit time through a lymph node
Approx. 18 hours
A condition where lymph nodes are enlarged due to the accumulation of lymphocytes and other cells
Lymphadenopathy
Small polypeptides that regulate the functions of lymphocytes and other cells involved in the immune response
Cytokines
Receptor for HIV
CD4 (Helper T cells, monocytes, macrophages)
Involved in T-cell activation
CD2 (thymocytes, T cells, NK cells)
Essential in T and B cells antigen-stimulated activation
CD45R (hematopoietic cells)
The earliest B-cell precursor can be recognized by the presence of a surface molecule called
CD45R
A phase where B-cell precursors go through a developmental process that prepares them for their role in antibody production and, at the same time, restricts the types of antigens to which any one cell can respond.
Antigen-independent phase
Surface antigens of Pro-B cell as distinctive markers
CD19, CD45R, CD43, CD24, and c-kit
Intracellular proteins found in Pro-B cell stage
Terminal deoxyribonucleotide Transferase (TdT)
Acts as a coreceptor that helps reguate further B-cell developement and activation
CD19
A membrane glycoprotein found on all hematopoietic cells that is the largest form found on B cells
CD45R
Synthesis of the heavy chain part of the antibody molecule
pre-B stage
The first heavy chains that are synthesized
μ chains (belongs to the IgM class)
**
Chains that consist of two short polypeptide chains that are non-covalently associated with each other. They are not immunoglobin proteins but essential for regulating B-cell development
Surrogate light chain
This receptor adheres to bone marrow stromal cell membranes and transmits a signal to prevent rearrangement of any other heavy-chain genes
Pre-B cell receptor
This refers to when IgM or IgD becomes IgG
Isotype switching
Distinguished by the appearance of complete IgM molecules on the cell surface
Immature B cells
This indicates that rearrangement of the genetic sequence coding for light chains on either chromosome 2 or 22 has taken place by this time
Immature B cells
Surface proteins that appear on the immature B cell include
CD21, CD40, and MHC class II molecules
A process where many B cells capable of producing antibody to self-antigens are deleted from the marrow
Apoptosis or programmed cell death
In the spleen, immature B cells develop into mature cells known as
marginal zone B cells
Other immature B cells become _____________ , which are found in lymph nodes and other secondary organs
follicular B cells
What cells remain in the spleen and what cells constantly recirculate throughout the secondary lymphoid organs?
marginal B cells; follicular B cells respectively
In addition to IgM, all mature B cells exhibit this immunoglobulin, another class of antibody molecule, on their surface which is not required for B-cell function but may prolong the life span of mature B cells in the periphery
IgD
A phase where a B cell is stimulated by antigen, it undergoes transformation to a blast stage, which eventually forms memory cells and antibody secreting plasma cells
antigen-dependent phase of B cell development
Life span of B cells
Half-life of more than 6 weeks
Surface marker for activated B cells
CD25
Life activates at age 25 < yes i know it begins at 30 pero baket ba >
Growth factor produced by T-cells
Interleukin 2 (IL2)
Give rise to both plasma cells and so called memory cells.
Activated B cells
Spherical or ellipsoidal cells between 10 and 20 μm in size and are characterized by the presence of abundant cytoplasmic immunoglobulin and little to no surface immunoglobulin
Plasma cells
The appearance of the plasma cell nucleus and chromatin
nucleus - eccentric or oval
chromatin - heavily clumped that stains darkly
This represents the most fully differentiated lymphocyte, and its main function is antibody production
Plasma cells
True or false. Plasma cells and memory cells are normally found in the blood.
False uy! Sa germinal center siya bestie. Tarungin mo ako!
Increase in nonmalignant disorder such as in viral diseases
Plasma cells
How many percent of circulating lymphocytes are T cells?
60-80%
Lymphocyte precursors
Thymocytes
Early surface markers on thymocytes that are committed to becoming T cells
CD25 or CD44
Si Belen nga 25 years old gusto na ma aunTIE nga 44 years old
Early thymocytes lack CD4 and CD8 markers, which are important to their later function; hence they are known as
double-negative thymocytes
At this second stage, when thymocytes express both CD4 and CD8 antigens, they are called
double positive stage
Allows only double positive cells with functional TCR receptors to survive
positive selection
Takes place among the surviving double-positive T cells
negative selection
Mature T cells are survivors of selection that exhibit only one type of marker, either
CD4 or CD8
Identify the surface marker:
“Inducer cells” MHC Class II
CD4
Identify the surface marker:
“Cytotoxic cells” MHC Class I
CD8
Th cells that produce interferon gamma (IFN-γ) and tumor necrosis factor-beta (TNF-β), which protect cells against intracellular pathogens.
Th1 Cells
Essential role of this Th cells is to help B cells produce antibody against extracellular pathogens
Th2 cells
Identified by rosette formation with SRBCs
T cells
Identified by surface immunoglobulin
B cells
They have the ability to mediate cytolytic reactions and kill target cells without prior exposure to them
NK Cells
True or False. The fact that NK cells lack specificity in their response is limiting to their function as early defenders against pathogens.
False. It is essential to their function because they can defend the body against any pathogen and that would give time for the acquired response to be activated.
Allows NK cells to attach to and lyse any cells that are coated with antibody
CD16
Protein expressed on all healthy cells
MHC Class I protein
A signal given once it recognizes your MHC class I protein
Inhibitory signal
Deliver signals to activate the cytotoxic mechanism.
Activating receptors
The second method of destroying target cells is also available to NK cells. This time they recognize and lyse antibody coated cells to a process known as
Antibody-dependent cell
cytotoxicity
Under antibody-dependent cell cytotoxicity, any target cell coated with this immunoglobulin can be bound and destroyed
IgG
Pore-forming proteins that polymerize in the presence of Ca2+ and form channels in the target cell membrane
Perforins
Packets of serine esterase enzymes that may enter through the channels and mediate cell lysis
Granzymes
One of the most frequently used methods for obtaining lymphocytes is density gradient centrifugation with
Ficoll-Hypaque
Specific gravity of Ficoll-Hypaque
1.077 - 1.14
The rosette technique uses
RBCs from sheep
It is considered a rosette if
three or more RBCs are attached to a lymphocyte
Receptor on T cells responsible for rosetting with sheep red blood cells
CD2
The principle leukocyte associated with phagocytosis and localized inflammatory response.
Neutrophils
The movement of granulocytes from the circulating pool to the peripheral tissue is called
diapedesis
A homeostatic regulator of inflammation that has the ability to kill certain parasites.
Eosinophils
It has high concentration of heparin and histamine in their granules which play a role in acute system hypersensitivity reactions.
Basophils
Produced by basophils that are able to mediate inflammatory functions of leukocytes
leukotrienes
Constituent demonstrating no change in activated macrophages
Lysozyme
