ImmunoSero Lecture (Immune System) Flashcards by CHENNEDETTE RESYL MAGLANGIT

Embryonic blood cells, excluding your lymphocytes, originates from the ________________ which is from the embryonic germ layer which is the ____________.

mesenchymal tissue; mesoderm

How well did you know this?

Not at all

Perfectly

Where the first blood cells (primitive RBCs; erythroblasts) are formed during the first 2 to 8 weeks of life.

Islets of the yolk sac

How well did you know this?

Not at all

Perfectly

Replaces the yolk sac as the site of blood cell development

Liver and Spleen

How well did you know this?

Not at all

Perfectly

The major site of hematopoiesis by the second month of gestation where granular types of leukocytes initially appear

Liver

How well did you know this?

Not at all

Perfectly

During hematopoiesis, these predominate from about 2 to 5 months of fetal life.

Liver and Spleen

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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)

How well did you know this?

Not at all

Perfectly

The cellular elements of the blood are produced from …

Multipotential hematopoietic stem cell (Hemacytoblast) CD34 & CD45

How well did you know this?

Not at all

Perfectly

Major cellular elements of the circulating blood.

Erythrocytes (RBCs)
Thrombocytes; and
Specific types of Leukocytes (WBCs)

How well did you know this?

Not at all

Perfectly

Primary lymphoid organs

Bone Marrow
Thymus

How well did you know this?

Not at all

Perfectly

Where all lymphocytes arise from that resides in one of the primary lymphoid organs which is in the bone marrow

Pluripotential hematopoietic stem cells

How well did you know this?

Not at all

Perfectly

Among the primary lymphoid organs which is solely dedicated to the T-cell.

Thymus

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

The main site for the maturation of your B cells in the peripheral blood.

Bone marrow

How well did you know this?

Not at all

Perfectly

Approximately, __________% of leukocytes are B cells, __________ % are NK cells, and the rest are T cells.

10 to 20% - B cell leukocytes
22% - NK cells

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

This is where T-cell maturation and the acquisition of surface antigens occur.

Thymus

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

Secondary lymphoid organs
< PAT MLS >

Peyer’s patches
Appendix
Tonsils
Mucosal-associated lymphoid tissue
Lymph nodes; and
Spleen

How well did you know this?

Not at all

Perfectly

Play a role in antigen dependent lymphopoiesis

Secondary lymphoid organs

How well did you know this?

Not at all

Perfectly

The secondary lymphoid tissues are found in these tracts.

Gastrointestinal Tract
Respiratory Tract
Urogenital Tract

How well did you know this?

Not at all

Perfectly

These are localized at some of the main ports of entry for foreign organisms

Marcophages and Lymphocytes

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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 H**IV**

CD4 (Helper T cells, monocytes, macrophages)

Involved in T-cell ac**t**iva**t**ion

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 rose**tt**e formation with SRBCs

T cells

Identified by surface immunoglo**b**ulin

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