What is antigen synthesis?
It’s the process of how the antigen causes the synthesis of specific antibodies.
Stem cell in the bone marrow differentiate into what 3 categories?
Erythrocytes, granulocytes and monocytes
What do stem cells become alternatively?
Lymphoid stem cells
Lymphoid stem cells subdivide into which two categories?
B Lymphocytes (B cells) and T lymphocytes (T cells).
Why do we them B lymphocytes?
They were first recognized in birds in the lymphoid organ in the lower gut called the bursa of Fabricius
In humans, where does the B cell (lymphocytes B) differentiation take place?
in the fetal liver and in adult bone marrow
Why do we name them T cells?
The differentiation takes place in the thymus
Where do the T and B cells migrate to in the human body?
The lymphoid tissue
Where are B and T cells mostly found in the human body?
Lymph nodes, spleen, bone marrow and gastrointestinal tract.
What occurs to B cells when they are activated by an antigen?
They synthesize the antibodies that are responsible for humoral immunity.
What occurs to T cells when they are activated by an antigen?
They bring about cellular immunity and play a role in humoral immunity.
What are self antigens?
Self antigens are proteins on vertebrate cell surfaces.
What does MHC stand for?
Major histocompatibility complex
True or false. Self antigen are referred to MHC
True
Where are Class I MCH cells found?
- Found on all nucleated vertebrate
2. Only red blood cells are non-nucleated
Where are Class II MCH cells found?
On cells involved in the humoral response such as Macrophage, dendritic cells and B cells.
What are dendritic cells?
Antigen cells presenting cells for T cells.
Fill in the blank. MHC antigens indicate self, but also act as a _______ for foreign antigens.
Molecule.
What is a B cell
A B cell binds the antigen, internalize it, and degrades it into smaller fragments.
True or false. Some fragments from the B cell are re-deposited on the cell surface, each in combination with an MHC class II antigen.
True
How does the B cell bind the antigen?
Because it has an appropriate surface receptor.
What is a surface receptor?
A copy of the antibody that the B cell is capable of synthesizing.
What is the abbreviation for Antigen presenting cells
APC
What types of cells are APCs?
Macrophages and dendritic
What does the APC do?
The APC binds the antigen, internalizes it by endocytosis and degrades it into smaller pieces.
Fill in the blank. The smaller remnant fragments from the APC can have some fragments bind to an MHC class __ molecule and are deposited on the cell _____.
Class II
Deposited on the cell’s surface
True or false. T cells can interact with intact antigen.
False. They can’t
Fill in the blank. It requires the ____ to process the antigen and present it as an _____ fragment
APC
Antigen fragment.
How does the T cell bind to the antigen fragment
The APC must process the antigen and present it into fragments, then the T cell via the T cell receptor, binds the antigen fragment.
T cells are subdivided into what to categories?
CD4+ CD8-
CD8+ CD4-
What are CD4+ are also known as?
Helper cells or TH cells
What are the two subsets of the TH cells?
TH1 and TH2
What are TH1 cells required in?
In cellular immunity
What are TH2 cells required in?
In humoral immunity
What are Tc cells also called?
Cytotoxic cells
What do Tc cells do?
They recognize a foreign antigen on the surface of a target cell and lyse the cell via cell to cell contact
True or false. T independent antigens can bind to B cells and directly induce antibody synthesis.
True
Fill in the blanks. In the T cell dependant antibody synthesis has an APC that binds to an ______ and processes it.
Antigen
Fill in the blanks. A TH2 cell binds to the processed antigen which causes the ___ to secrete a substance called ___
APC
Interleukins
What does the interleukins cause the TH2 to do?
To divide and to synthesize and secrete other interleukins.
Fill in the blank. Interleukins cause ________ of the TH2 cells (specific to the antigen presented on the APC). TH2 cell can be referred to as _____ cells.
Proliferation
Activated TH2 cells
Fill in the blanks. An activated TH2 cell binds to the antigen _____on the surface of the _____ and then secretes several ______
Fragment
B cell
Interleukins
Fill in the blank. Other interleukins cause some _____ to stop multiplying and to differentiate into ____ cells and memory cells.
B cells
Plasma
True or false. Plasma cells can survive for about one week, but they synthesize large quantities of antibody
True
True or false. Memory cells live long and after being exposed turn into plasma cells
True
True or false. Memory cells account for dramatic secondary response (anamnestic response)
True
What is another term for cellular immunity
Cell-mediated immunity
Fill in the blanks. Cellular immunity is a ______ system of immunity possessed by _____
second
vertebrates
Cellular immunity is most directed to what (name 7)
Whole cells (virions) bacteria fungi, protozoa viruses foreign tissues (their MHC antigens) tumours
Cellular immunity depend on the presence of what two groups of lymphocytes?
T cells
Large granular lymphocytes
True or false. T cells are TH1 and TC cells
True
Fill in the blank. The LGL group is composed of natural ____ and a derivative of NK cells called ________(LAK cells)
Killer cells
lymphokine activated killer cells
What does an APC do during cellular immunity?
It binds to the processed antigen
What does the TH1 do during cellular immunity?
It binds to the processed antigen
Interleukin production by two cells cause TH1 cell ________ and ______ into activated TH1 cells and memory TH1 cells
Proliferation and differentiation
Activated TH1 cells secrete what? Name two
Gamma interferon
Necrosis factor-beta (TNF-beta)
True or false. Gamma interferon stimulate macrophages?
True
What does TNF beta do?
Lyses foreign cells.
Tc cells recognize antigen bound to what on cell surfaces and lyse the displaying cell?
MHC class I molecules.
What is the primary role of Tc cells?
To destroy self cell that have acquired non self surface antigens.
Natural killer cells kill what types of cells. Where are their antibodies located?
NK cells kill malignant cells. They have their antibodies bound to their surface.
What are LAK cells
Lymphokine activated killer cells.
NK cells treated with interleukin 2 have increase in what?
Cytolytic ability
Hypersensitivity is considered what?
A condition which the immune system overreacts and causes injury to the host
True or false. A Hypersensitivity is when the antigen-antibody reaction or the antigen T cell reaction is harmful
True
What two types of hypersensitivity exist?
A delayed hypersensitivity and a immediate hypersensitivity
An immediate hypersensitivity is mediated by _____
Antibodies
In immediate hypersensitivity reactions, the _________is harmful than beneficial
Antigen-antibody
Name example of immediate hypersensitivities.
Systemic allergies
Anaphylaxis
Serum thickness
Localized allergies such as asthma, hay fever and urticaria
What is considered the sensitizing dose?
The dose of antigen to which an individual becomes sensitive to.
What is the eliciting dose?
The subsequent dose of antigen that causes tissue damage.
What is the shocking dose
When the injury is severe due to the exposure to the subsequent dose of antigen
Name the four labels of allergens
injectants, inhalants, ingestants and contactants
Name the antibodies involved in hypersensitivity
the lgE class
True or false. The lgE is formed in response to the sensitizing dose of antigen?
True
What do the lgE attach themselves to if they do not circulate freely in the blood?
Mast cells and basophils.
Define mast cells.
They are connective tissue cells found adjacent to blood capillaries throughout the body.
What physiological events does the eliciting dose set off? name 3
- The antigen molecule combines with lgE antibodies are attached to mast cells and basophils.
- The mast cells and basophils release histamine.
- Other than histamine, the other substances released are: dilatation of blood arterioles
- contraction and spasm of smooth muscles (bronchioles)
- increase capillary permeability with edema
What symptoms are characterized as anaphylactic shock?
- Blood pressure drop
- Contractions of smooth muscles and severe bronchospasm
- Edeme causes laryngeal constriction
A delayed hypersensitivity is mediated by sensitized ____ cells.
T
In delayed hypersensitivity, the antigenic stimulus is exaggerated, therefore the ______ cell reaction is harmful rather than beneficial.
Antigen-T
Give 2 examples of delayed hypersensitivities
- tuberculin skin test reactions
2. contact dermatitis
Define an immunodeficiencies
A condition where there’s an underperformance in humoral immunity or cell-mediated immunity.
Define iatrogenic
induced inadvertently by a physician or surgeon or by medical treatment or diagnostic procedures
True or false. Immunodeficiencies can be the cause of congenital, iatrogenic, malignancies and of the lymphatic system
True
Immunodeficiencies are abnormalities of what type of cells ?
B cell, T cell or the combination of the 2
Name two types of diseases that are due to immunodeficiencies due to B cell abnormalities?
- Hypogammagloculinemia
2. Afammaglobulinemia
Define hypogammaglobulinemia
A decrease in production in antibodies
Define agammaglobulinemia
The complete failure of immunoglobulin production. It’s a congenital defect
Name a syndrome that is caused by immunodeficiencies due to T cell abnormalities
DiGeorge’s syndrome
Explain DiGeorge’s syndrome
It’s a congenital absence of thymus glans or the formation of a basic thymus gland. Children with this disease must be raised in complete protective isolation
Name a condition that is due to abnormal B cell and T cells.
Swiss type immunodeficiency or Swiss type agammaglobulinemia.
Define Swiss type disorter
Congenital absence of lymphoid stem cells result in the absence of B and T cells.