Adaptive Immunity Summary

Adaptive Immunity

Daniela Castaño Ramirez 8°

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1. Production of antibodies

What are antibodies? Antibodies are the secreted form of the BCR of an activated B cell, and these antibodies react to the same antigen as the original B cell did.

Production process

Figure 33.9 page 625 section 33.4

• Many B cells are present, but only those who have BCRs can combine with their specific antigen and create new cells.
• The B cell is activated when their BCRs (B- cell receptor) binds to their specific antigen.
• The B cells makes clones of itself when the last step happens
• Many of the activated B cells, become plasma cells which are the ones that secrete antibodies.

Secretion is a process by which substances are produced and discharged from a cell (in this case the plasma cell) for a particular function in the organism (production of antibodies)

• Besides, the cloned, smaller B cells, become memory B cells, and are the ones that remember a paticular antigen and makes us immune to the illness the antigen has.

2. Structure and types

Of antibodies

Structure of antibodies

Figure 33.10 page 225 section 33.4

Is a Y-shaped protein molecule with two arms. Each arm has a heavy and a light polypeptide chain. The antigen combines with the antibody in a lock-and-key manner, since they are specific between eachother.

Click on the numbers

Types of antibodies

Also called immunoglobulins (Ig). Are determined by the structure of the antibody's constant region (seen in 'structure of antibodies'

• IgG = Major class of antibody found in the blood. A single Y-shaped molecule.
• IgA = Main class secreted in milk, tears, and saliva and at mucous membranes.

• IgM = Clusters of five Y-shaped molecules linked together. Usually the first antibodies produced during B cell responses.
• IgE = Bound to receptors on eosinophilis and on most cells in the tissues.

Monoclonal antibodies

• They are produced by cells derived from a single plasma cell. But they are still specific to one antigen.
• Typically produced by first immunizing an animal with the antigen of interest.
• Fused cells between spleen cells, B cells and myeloma cells are called hybridomas.
• The hybridomas are isolated as indivicual cells and select the desired monoclonal antibody.

3. B and T cells

And their roles

They are in charge of the production of memory B cells. They are also in charge of the production of both plasma cells and antibodies.

B cells role

T cells make Memory T cells. And, they are responsible for Cell Mediated Immunity, which detects antigens and eliminates pathogens within cells.

T cells role

Two major types of T cells

Helper T cells (Th cells)

Cytotoxic T cells (Tc cells)

Recognize and respond only to antigens presented by APCs (antigen-presenting cells with MHC (major histocompability complex) class II on their surface.

Recognize and respond only to antigens presented by various types of cells with MHC class I proteins on their surface.

Similarities of B and T cells (and diferences)

Both of them are manufactured in the red bone marrow.

However, B cells mature in the red bone marrow.

Both cell types have antigen receptors on their plasma membrane

While, T cells mature in the thymus.

Because of the receptors, they are able to recognize specific antigens.

4. Memory cells

Role and importance

Role of memory cells

They remember pathogens seen and identified by B cells or T cells previously, thanks to these cells receptors.

Importance

Of memory cells

They are important since they are the ones to record information which explains and instructs the body on how to fight certain illness you might've previously had by producing antibodies.