Chapter 15: Adaptive, Specific Immunity and Immunization

What are key characteristic of the adaptive immune system?

It is the third line of defense with dual systems of B and T lymphocytes; features Specificity (where antibodies are produced) and memory cells.

How is B cell and T cell receptors similar?

Both begin in the bone marrow.

How is B cell and T cell receptors different?

B cells stay in the bone marrow and are bind free antigens.

T cells migrate to the thymus and bind processed antigens together with the MHC molecules on the cells that present antigens to them; they are smaller and aren't secreted.

What is MHC or Major Histocompatibility Complex?

One set of genes that encodes for human cell markers, they are found in all cells except red blood cells.

Where do T and B cells mature?

T cells mature in the thymus

B cells mature in the bone marrow.

What is clonal selection?

A theory to explain that each lymphocyte has immunoglobin receptors specific to a particular antigen.

What part of the antibody does antigen bind to?

The antigen binding fragments that bind to specific antigens.

What is the difference between an antigen and a hapten?

Antigens are substances that provoke an immune response to specific lymphocytes,

Haptens are small foreign molecules that consist only of a determinant group.

Define an alloantigen.

(Ex: Blood typing)

Cell surface markers and molecules that occur in some members of same species but not in others.

Define a superantigen.

Potent T cell stimulators; provoke an overwhelming response.

Define allergen.

Antigen that evokes allergic reactions.

Define autoantigen.

Molecules on self tissues for which tolerance is inadequate.

Define opsonization.

Process of coating microorganisms or other particles with specific antibodies so they are more readily recognized by phagocytes.

Define neutralization.

Antibodies aggregation; cross-linking cells or particles into large clumps to immobilize them, making phagocytosis easier.

Define complement fixation.

Activation of the classical complement pathway can result in the specific rupturing of cells and some viruses.

Define precipitation.

Aggregation of small, free antigen.

Describe the process of T-cell dependent activation.

-Antigen presenting cells modify the antigen; then the antigen is moved to the APC surface and bound to the MHC receptor,

-Antigen presentation involves a direct collaboration among an APC, and T-helper cells,

-Activation of the T-helepr cells by secreting Interleukin-I

-Interleukin-II is produced to activate B cells and other T cells.

What are some key characteristics of IgG?

Long-term immunity; memory antibodies; neutralizes toxins and viruses.

What are some key characteristics of IgA?

Secretory antibody; on mucous membranes.

What are some key characteristics of IgM?

Produced at first response to antigen, can serve as B-cell receptor.

What are some key characteristics of IgD?

Receptor on B cells for antigen recognition.

What are some key characteristics of IgE?

Antibody of allergy; worm infections.

What is primary immune response?

After first exposure to antigen, immune system produces IgM and a gradual increase in antibody titer with production of IgG followed by IgM.

What is secondary immune response?

After second contact with the same antigen, immune system produces a more rapid, stronger response due to memory cells.

What are the different types of T cells?

T-helper cells and Cytotoxic T cells.

What are the differences between the two types of T cells?

T-heper cells have CD4 on the surface and activates other CD4 and CD8 cells,

Cytotoxic T cells have CD8 on the surface and destroys a target foreign cell by lysis.

What is active immunity?

Results when a person is challenged with antigen that stimulates production of antibodies; creates memory, takes time, and is lasting.

What is passive immunity?

Performed antibodies are donated to an individual; does not create memory, acts immediately, and is not lasting.

What is natural immunity?

Acquired as part of normal life experiences.

What is artificial immunity?

Acquired through a medical procedure such as a vaccine.

What are the disadvantages of a killed vaccine?

It requires a larger dose, and more than one dose.

What are the disadvantages of a live vaccine?

There is a risk of getting sick and can revert back to its virulent strain.

What are the advantages of a killed vaccine?

People cannot get sick from it.

What are the advantages of a live vaccine?

It is altered to not be as pathogenic and requires a smaller dose.

What is herd immunity?

Immune individuals will not harbor it, reducing the occurrence of pathogens.