Lymphatic System Part 2

Any substance capable of provoking an immune response.

Antigen

Kind of antigen: Known as foreign intruders. Provoke the strongest responses.

Nonself antigen

Kind of antigen: Do not trigger an immune response. They are strongly antigenic to other people.

Self-antigens

A non-antigenic troublesome small molecule that the immune system may recognize it as foreign and mount an attack that is harmful rather than protective.

Hapten (incomplete antigen)

Examples of Hapten

1. Poison Ivy

2. Animal Dander

3. Detergents

4. Hair Dyes

5. Cosmetics

2 MAJOR “FLAVORS” OF LYMPHOCYTES

1. B lymphocytes (B cells)

2. T lymphocytes (T cells)

Flavor of lymphocyte: Produces antibodies and oversee humoral immunity

B lymphocytes (B cells)

Flavor of lymphocyte: constitute the cell-mediated arm of the adaptive defenses and do not make antibodies.

recognize and eliminate specific virus-infected or tumor cells

T cells

Capable of responding to a specific antigen by binding to it with antigen-specific receptors that appear on the lymphocytes surface

Immunocompetent

Where do T cells migrate after arising from the lymphocytes?

Where do B cells develop immunocompetence?

Thymus

Bone marrow

Engulf antigens and then present fragments of them, like signal flags, where they can be recognized by T cells

Antigen-presenting cells (APC)

Major types of cells acting as APCs:

1. Dendritic Cells

2. Macrophages

3. B lymphocytes

Process in which lymphocytes begins to grow and then multiplies rapidly to form an army of cells exactly like itself and bearing the same antigen-specific receptors.

Clonal Selection

The resulting family of identical cells descended from the same ancestor cell.

Clones

Clone formation to the antigen

Primary Humoral response

Most of the B cell clone members (descendants) become?

Plasma cells

B cell clone members that do not become plasma cells. They are capable of responding to the same antigen if they “see” it again.

Memory cells

Later immune responses

Secondary Humoral responses

When B cells encounter antigens and produce antibodies against them

Active Immunity

2 WAYS ACTIVE IMMUNITY IS ACQUIRED

1. Naturally acquired (during bacterial and viral infections)

2. Artificially acquired (during vaccinations)

It is when B cells are not challenged by the antigen. Antibodies are obtained from the serum of an immune human or animal donor.

Passive immunity

2 WAYS PASSIVE IMMUNITY IS ACQUIRED

1. Naturally (on a fetus, when the mothers antibodies cross the placenta)

2. Artificially (person receives immune serum or gamma globulin)

Descendant of a single cell and are pure antibody preparations tha texhibit specificity for only one antigen.

Monoclonal antibodies

referred to as Immunoglobulins. Formed in response to a huge number of different antigens.

Antibodies

The four chains forming an antibody composes of what 2 regions?

Variable (V) region and Constant (C) region

When variable regions of the heavy and light chains combine their efforts

antigen-binding site

Ways antibodies inactivate antigens

1. complement fixation

2. neutralization

3. agglutinationn

4. opsonization

5. precipitation

chief antibody ammunition used against cellular antigens

Complement

Antibody binding “tags” antigen for phagocytosis

Opsonization

occurs when antibodies bind to specific sites on bacterial exotoxins that causes cell injury.

Neutralization

Cross-linking reaction

Precipitation

Process causes clumping of the foreign cells

Agglutination

Immunoglobulin/s that is/are PENTAMERS

IgM

Immunoglobulin/s that is/are BOTH MONOMERS and DIMERS

IgA

Immunoglobulin/s that is/are MONOMERS

IgD, IgG, and IgE

Immunoglobulin: attached to B cell, seves as antigen receptor, fixes complement

IgM

Immunoglobulin: monomer in plasma, dimer in secretions (saliva, tears), protects mucosal surfaces

IgA

Immunoglobulin: almost always attached to B cell, cell surface receptor of immunocompetent B cell, activation of B cell

IgD

Immunoglobulin: Most abundant antibody in plasma, 75% - 85%, crosses placenta, immunity to fetus, fixes complement

IgG

Immunoglobulin: Secreted by plasma cells in skin, respiratory tracts and tonsils, binds to mast cells, triggers release of histamine

IgE

secrete their antibody weapons

B cells

fight their antigens directly in “cell-to-cell combat”

T cells

2 TYPES OF T CELLS INVOLVED IN THE ACTIVATION PROCESS

Helper T cells and Cytotoxic T cells

process known to be essential for the activation and clonal selsction of T cells

antigen presentation

chemicals released by macrophages and dendritic cells

Cytokine

specialize in killing virus-infected, cancer, or foreign graft cells directly

Cytotoxic T cells

T cells that act as the “directors” or “managers” of the adaptive immune response

Helper T cells

T cells that releases chemicals that supress the activity of both T and B cells

Regulatory T cells

4 major types of transplants or grafts

Autografts, Isografts, Allografts, Xenografts

are tissue grafts transplanted from one site to another in the SAME PERSON

Autografts

tissue grafts donated by a GENETICALLY IDENTICAL PERSON (e.g identical twin)

Isografts

tissue grafts taken from a PERSON OTHER THAN AN IDENTICAL TWIN

Allografts

tissue grafts harvested from a DIFFERENT ANIMAL SPECIES (e.g pig heart valve transplanted to human)

Xenografts

Ideal donor organs/tissues

Autografts and Isografts

It is done after surgery to prevent rejection of transplants

immunosuppressive therapy

What line/s of defense belongs in the innate defense mechanisms

first line and second line of defense

What line/s of defense belongs in the adaptive defense mechanisms

third line of defense

What line of defense do “skin, mucous membranes, and secretion of skin and mucous membranes” belong?

first line of defense

What line of defense do “phagocytic cells, NK cells, antimicrobial proteins, inflammatory response, and fever” belong?

second line of defense

What line of defense do “lymphocytes, antibodies, and macrophages and other antigen-presenting cells” belong?

third line of defense