Lecture 21 Flashcards
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