Specific Immune Response (Primary Immune Response) Flashcards
What happens after the macrophage engulfs biological material?
Protein fragments (peptides) from the material become attached to proteins in the cell.
Where are the protein fragments added to?
Protein fragments are added to the macrophages cell surface membrane, displayed as ‘non-self’ antigens
What do the antigens on the cell surface of macrophages act as?
Antigens presented on the surface of macrophages act as a signal to alert the immune system to the presence of foreign antigens in the body.
What is the name given when macrophages present with non-self peptides on it’s cell surface membrane?
Macrophages display non-self peptides are antigen present cells (APCs)
What are T helper cells with a complementary shape called?
CD4 receptor
What do the CD4 receptors bind to?
Binds to the antigen on the surface of the antigen-presenting cells
How is the CD4 activated? What does it do once it is activated?
activated by this binding, each T helper cell divides to produce a clone of active T helper cells and clone of T memory cells
How long do the Second Clones remain the body for? What are the benefits of this?
→ Second Clone remains for years or months in the blood → If individual is exposed to the same antigen in the future, their immune system responds more quickly.
Activation of T Cells (6)
- Bacterium with antigens on surface 2. Bacterium engulfed by macrophage 3. Macrophage presents antigens on it’s surface and becomes an antigen-presenting cell (APC) 4. APC bind to T helper cell with complementary CD4 receptors 5. T helper cell is activated and divides 6. Clone of T memory cells is produced + Clone of active T helper cells
What do complementary receptors on the surface of B Cells bind to?
→ Complementary receptors on the surface of B Cells bind to non-self antigens + become antigen presenting cells in the same way macrophages do.
What do Antigen presenting B Cells do?
→ Antigen-presenting B Cells bind with active, cloned T helper cells that are presenting the same antigen
After becoming attached to active cloned T helper cells that present the same antigen what happens next? What chemical is released?
attached, the T helper cells release chemicals called cytokines which stimulate division + differentiation of the B cells
What happens to the B cells under the influence of cytokines?:
Under the influence of cytokines: B cells divide to produce two clones of cells: B effector cells B memory cells
What do B effector cells do?
Differentiate to produce plasma cells: release antibodies into the blood + lymph (short lived)
What do B memory cells do?
Like T memory cells: longer lived + enables individual to respond more quickly to the same antigen in the future.
What is B Cell Division also known as?
Clonal Selection
Why is it called the Primary Immune Response?
First time a B Cell comes across a non-self antigen that is complementary to it’s cell surface receptors: production of sufficient antibody-producing cells takes 10-17 days PRIMARY IMMUNE RESPONSE
During the time its takes to produce antibodies during the primary immune response what happens to the person?
During time it takes to produce antibodies, person suffers symptoms.
Cloning of B Cells (6)
- Bacterium with antigens on surface. 2. Antigens bind to B cell with complementary receptor 3. B Cell becomes an antigen-presenting cell (APC) 4. Activated T helper cell with complementary receptor binds to APC and produces cytokines (proteins) that stimulate the B cell 5. Clone of B memory cells and Clone of B effector cells are produced 6. B effector cells differentiate into plasma cells 7. Plasma cells secrete antibodies which bind to antigens, identifying them for easier destruction.
Complementary Protein Shapes
-Lock + Key for enzyme specificity -Relies on recognition of specific protein antigens by T helper and B cells using receptors with complementary shape Specific shape of the binding sites found on antibodies is crucial to their function.
What happens to the antigen on the surface of a bacterium or virus when it invades a body cell?
Bacterium or virus infects a body cell, a fragment of the antigen is presented on the cell surface membrane, in the same way it occurs in a macrophage.
What do T cells bind to?
T killer cells with complementary receptors bind to the antigen presented on the body cell
What do T killer cells divide to form? What is this division stimulated by?
T killer cells divide to form an active clone; this division is stimulated by the cytokines from T helper cells.
What happens if there is not enough cytokines?
Without cytokines, not enough T killer cells produced to fight a viral infection.
What do T killer cells release?
T killer cells release enzymes that create pores in the membrane of the infected cell.
What do the pores that the T killer cells create do to the cell?
Enables ions + water to flow into the infected cell, which swells + bursts (lysis) Pathogens within the cell are released
What happens when the cell bursts?
Once the cell can be burst, pathogens are out of the cell + labelled by antibodies from B cells as targets for destruction by macrophages.
T Killer Cell (6)
- Bacterium infects cell of host. 2. The cell product, presents the antigens + become APC 3. T killer cell with complementary receptor binds to the APC 4. T killer cell divides to form two clones: active + memory T killer cells. Cytokines from T helper cells differentiate stimulate differentiation. 5. The active T killer cells bid to infected cells presenting antigens 6. T killer cell releases chemicals that cause pores to form in the infected cell, causing lysis. Infected cell is destroyed
