L25 Adaptive Immunity

What specific types of white blood cell are involved in adaptive immunity?

Lymphocytes

What macromolecule induces an immune response and contains a part that binds to the Ag receptor of B or T cells?

Antigen (Ag)

What part binds to the Ag receptor of B or T cells?

Epitope

What are the 4 major characteristics of adaptive immunity?

1. B cell and T cell diversity

>10⁶ B cell Ag receptors

>10⁷ different T cell Ag receptors

2. Self - tolerances

3. Clonal selection of B cells + T cells

4. Immunological memory

What is immunological memory?

Long-term protection occulting from prior infection.

What are the characteristics of a primary immune response?

1st expose to an Ag ( antigen)

Peaks 10-17 days after initial exposure

Selected B cells & T cells give rise to effector forms

What are the characteristics of a secondary immune response?

Re-exposure to same Ag

Response

Faster (peaks 2-7 days after exposure)

Stronger &more prolonged

Requires less Ag

Result of B cell & T cell memory cells

Which cells have a Y-shaped Ag receptor with 4 polypeptide chains?

B-cells

What process occurs when Ag is present, BCR binds to Ag, the cell becomes activated, forms plasma cells, and secretes antibodies (Ab) also called immunoglobulin?

B cell activation

What cells are formed after activation and secrete antibodies (Ab)?

Plasma cells

What is the soluble form of BCR that is not bound to membrane and carries out defense against pathogens?

Ab (antibodies)

What lymphocytes have Ag receptors that bind only to fragments of Ag displayed (presented) on the host cell surface?

T cells

What are the the Ag receptors of T cells called?

T cell Ag receptors

How does adaptive immunity fight infection using specialized T cells?

Cell mediated response

How does adaptive immunity fight infection using antibodies?

Humoral response

What cells stimulate humoral & cell-mediated responses and do not kill pathogens themselves but tell other people to?

Helper T cells

What are the characteristics of an APC cell ( antigen-presenting cell)?

a dendritic cell, macrophage, or B cell that engulfs & degrades pathogen and displays Ag fragments complexed with class II MHC molecules.

What part binds to Ag fragment & to class II MHC molecule when a helper T cell binds to an APC?

Ag receptor

What accessory protein on helper T cell surface binds to MHC II & keeps cells joined?

CD4

What happens in response to the binding of helper T cells?

Stimulates APC & helper T cell to produce cytokines (signaling molecules)

Activates helper T cell & stimulates proliferation

Clone of helper T cells

Secrete other cytokines

Activate B cells & cytotoxic T cells

What type of immunity is artificial, induced by vaccination, produces Ab, and results in being immune if exposed naturally?

Active immunity

What shots induce a 2° response that results in a stronger response?

Booster shots

What methods include pathogen weakened or killed, maintain Ag & stimulate response, and lose ability to produce disease (or only mild symptoms)?

Vaccines

What type of immunity is borrowed immunity where an individual is given Ab actively produced by another organism, is temporary, and no memory cells are made?

Passive immunity

Ex: Rabies

Why is injecting Ab used for rabies in humans?

Rabies progresses quickly