Micro Chap 17
What cells produce perforin and granzyme? What do these chemicals do?
CD8+ cells produce these • Perforin: a pore forming protein that contributes to cell death • Granzyme: enter through the pore formed by perforin and induce apoptosis.
some components of microorganisms that are antigenic
Capsules, cell walls, flagella, fimbriae, toxins, viral capsids (spikes).
The recognition of antigen by T cells requires
That they be first processed by specialized antigen-presenting cells (APCs).
Which end of the antibody molecule interacts with complement or with phagocytes
The bottom of the Y.
Opsonization
The enhancement of phagocytosis by coating microorganisms with certain serum proteins (opsonins); also called immune adherence. Ex: C3b, Mannose-binding lectin (MBL)
Define apoptosis and explain its function.
The natural programmed death of a cell; the residual fragments are disposed of by phagocytosis. Functions to prevent the spread of infectious viruses into other cells.
clonal proliferation
When the immunoglobins of a B cell bind to the epitope of an antigen it is activated and undergoes clonal expansion.
What is the role of IgD? / Where is IgD found?
found in blood, lymph, and on the surfaces of B cells. It has no well defined function; assists immune response on B cells.
TH17 cells
found in the skin and lining of the GI tract; detect external pathogenic invaders and stimulate innate immune system
NK cells
component of innate immune system; granular leukocytes (10 - 15% of circulating lymphocytes) can also attack parasites that are much larger than bacteria; kill invaders with similar mechanisms as CTLs; different -- innate, don't need to be stimulated by antigen
Dendritic cells
have long extensions—dendrites; engulf invading microbes, degrade them, transfer them to lymph nodes for display to T cells; principal antigen-presenting cell (APC) to induce immune response by T cell
Macrophage
important for innate immunity, ridding body of worn out blood cells and remnants from apoptosis; once activated increased phagocytosis and migration to lymph nodes for APC
Activation of complement
inflammation caused by infection or injury -- microbes in inflamed area become coated with proteins -- attachment to the microbe of an antibody-compliment complex -- lyses the microbe and attracts phagocytes and other defensive cells
Is the immunity resulting from vaccination the result of innate or adaptive immunity?
Adaptive immunity results from a vaccination.
List the possible outcomes (results) of antibody binding to antigen
Agglutination, Opsonization, Activation of complement, Antibody-dependent cell-mediated cytotoxicity, Neutralization
How do antibodies protect us?
Antibodies interact with specific antigens and bind to epitopes (or binding site) on specific antigens.
Which Lymphocytes are most involved? -- Humoral
B Lymphocytes
IgE
0.002% in blood; found in mast cells, basophils; monomer structure; Allergic antibody; lysis of parasitic worms
antibody
A protein in the body in response to an antigen, and capable of combining specifically with that antigen.
IgA
10 - 15% in blood; found in secretions; dimer w/ secretory component; Rich supply in colostrum
IgM
5 - 10% in blood; found in lymph, B cells; pentamer structure; early timing; Fisrt antibody produced in response to infection
IgG
80% in blood; found in lymph, intestine; monomer structure; late timing; crosses placenta; Enhance phagocytosis; neutrolize toxins / virus
antigen
A substance that causes the body to produce specific antibodies or sensitized T cells. Usually foreign to the body, non self.
Other cells involved w/ T lymphocytes -- Cell-Mediated
Cytokines, macrophages, TNK
Other cells involved w/ B lymphocytes -- humoral -- protect against:
Extra cellular, bacteria, bacterial exotoxin, virus
What are the immunoglobulins?
Immunoglobins are antibodies.
Other cells involved w/ T lymphocytes -- Cell-Mediated -- Protect against:
Intracellular bacteria, viruses, cancer cells, transplanted tissue
Other cells involved w/ B lymphocytes -- humoral
Plasma cells make antibodies
Which Lymphocytes are most involved? -- Cell-Mediated
T Lymphocytes
Interleukins
a chemical that causes T cell proliferation
Chemokines
a cytokine that induces, by chemotaxis, the migration of leukocytes into infected areas.
TNF-α
a polypeptide released by phagocytes in response to bacterial endotoxins; strong factor in inflammatory reactions of autoimmune diseases—rheumatoid arthritis
Cytokines
a small protein released from human cells that regulates the immune response; directly or indirectly may induce fever, pain, or T cell proliferation
TH1 cells
activation of macrophages, enhanced activity of complement, B cells to make Ig, stimulate production of antibodies that promote phagocytosis
Neutralization
an antigen-antibody reaction that inactivates a bacterial exotoxin or virus
Agglutination
joining together or clumping of cells
cytokine storm
over production of cytokines; can be damaging to human body. Superantigens provoke a very intense immune response.
the role of CD8+ cells (Tc cells):
precursors to CTLs; target cells are altered with a pathogen, viral or tumor cells then divide and form CTLs
TH2 cells
produce cytokines that are associated primarily with the production of antibodies; stimulate eosinophils - fight parasites, B cells to make IgE, cells of CMI
When stimulated by antigen, B lymphocytes
proliferate and generate plasma cells which produce antibodies and memory cells which respond the next time the individual is exposed to the same antigen.
T-dependent antigens
require a T cell for antibody production; both B and T cells need to be activated and interact.
Antibody-dependent cell-mediated cytotoxicity
resembles opsonization in that the target organism becomes coated with antibodies; however, destruction of the target cell is by immune system cells that remain external to the target cell
T-independent antigens.
stimulate B cells directly without the help of T cells; generally provoke a weaker immune response than T-dependent.
antibody titer
the amount of antibody in serum.
