Final (Immuno Chapter 7 thru end of packet) Flashcards
B cells begin their lives in the BM. The initial __________________ differentiation step in BM ultimately leads to the mature naive B cells. Mature B cells migrate to secondary lymphatic organs/tissues such as spleen and lymph nodes and begin __________________ stages of B cell differentiation to plasma cells or memory B cells
antigen-independent, antigen-dependent
After B cells are activated by an antigen and helper T cells, the antibody is secreted by plasma cells. The Ab has 3 main functions in humoral immunity. What are they?
1) neutralization
2) opsonization
3) complement activation
Which Ab is always secreted first?
IgM
What is the major function of plasma cells?
secrete Abs
Which Abs can do neutralization? How do they do neutralization?
IgM, IgG, and IgA can neutralize the epitope by surrounding it and preventing the bacteria from multiplying
Which Ab is an opsonin? How does this work?
IgG coats the epitope to make it yummy for macrophages to eat it
Which complement protein is used in opsonization?
C3b
During the process of _____________, antigens are bound by Ab and/or complement molecules. Phagocytic cells express receptors that bind opsonin molecules; With the antigen coated with these opsonin molecules, binding of the antigen to the phagocyte is greatly enhanced.
opsonization
Some B-cells, do not differentiate into plasma cells, but remain as long-lived “___________”. Upon subsequent encounter with the same Ag, these memory cells undergo the immune memory phenomenon.
memory cells
_____________, also known as anamnestic response, is the rapid response with more Ab production with a booster shot or in a natural reencounter of antigen. Lymphocytes remember the past stimulation. After they encounter the same Ag again, B lymphocytes immediately go into action without much delay.
Immune memory
T/F: a vaccine is an antigen
true
What is class switching?
first Ab is always IgM
but then can switch to IgG, IgA, or IgE as needed
What is the difference between primary and secondary immune response with an antigen?
Cell Mediated Immunity is especially important for destroying intracellular bacteria, viral infections
and tumor cells. The effector cells involved in the Cell Mediated Immunity are….
-cytotoxic T lymphocytes (CTLs)
-NK-cells
-K-cells (killer cell, type of NK cell)
Cytotoxic T lymphocytes (CTLs), like other T-cells are both antigen and MHC-restricted. CTLs require:
recognition of a specific endogenous antigenic determinant; and recognition of “self” MHC. CTLs
recognize antigen via their T-cell receptor. This receptor makes specific contacts with the antigenic determinant and the target cell’s class ____ MHC molecule. CTLs also express CD____, which may assist the antigen recognition process.
1, 8
A host cell infected with a virus or cancer cell display the antigens on its surface complexed with a Class I MHC molecule. When recognition takes place, the CD8 co-receptor on the CD8 T cell binds to the MHC I on the Nucleated Cell. When activated CTLs recognize antigen fragments, the T cells begin to secrete toxins (______________________________) that cause lysis or apoptosis of the infected cell
perforin, granzymes, and granulysin
NK cells are part of a group know as the “large granular lymphocytes”. These cells are generally non-specific (Innate Immunity), MHC unrestricted cells involved primarily in the elimination of….
neoplastic or tumor cells
NK-cells contain immunoglobulin Fc receptors on their surface and are involved in ______________________ (ADCC). ADCC occurs as a consequence of antibody being bound to a target cell surface via specific antigenic determinants expressed by the target cell. Once bound, the Fc portion of the immunoglobulin can be recognized by the K-cell. Killing then ensues by a mechanism similar to that employed by CTLs.
Antibody-dependent Cell-mediated Cytotoxicity
Antibody-dependent Cell-mediated Cytotoxicity (ADCC) can result in type ____ hypersensitivities, for example, rheumatic fever from S. pyogenes
2
The complement system found in the blood of mammals is composed of 26 heat labile substances
(proteins) that combine with antibodies on cell surfaces. Most of the complement components are
numbered (e.g. C1, C2, C3, etc.) but some are simply referred to as “Factors”. The complement
system must be activated in order to function, which can be activated via three distinct pathways. All
of which lead to the production of C3 (the end of the early stage). What are the 3 pathways?
1) classical pathway
2) lectin pathway
3) alternative pathway
Are complement proteins always active?
no they circulate in the blood inactively until they’re needed
What cells produce complement proteins?
liver cells
Which complement protein pathway starts with an Ag-Ab complex/immune complex that binds together to make C1 and activates C2 + C4 to make C3 convertase?
classical pathway
Which complement protein pathway has a microbial mannose (sugar) interact with MBL (lectin) to make C3 convertase?
lectin pathway
Which complement protein pathway uses factor b and factor d to make C3 convertase?
alternative pathway
What 2 complement proteins make up C3 convertase in the classical pathway?
C2b and C4b
What is the function of C3b?
opsonization and phagocytosis
What is the function of C3a?
inflammation
What is the function of C5a?
inflammation
What complement proteins make up the MAC which leads to lysis of a microbe?
C5, C6, C7, C8, and multiple/polymerized C9
What are the 4 functions of the complement cascade/common pathway (this is once all 3 complement protein pathways make C3 convertase and now are the same pathway)?
***I’m assuming this will be a test question because he repeated it several times
1) opsonization by C3b makes bacteria more susceptible to phagocytosis
2) clearance of immune complex (immune complexes are small and help attach to RBCs to assist in clearance)
3) inflammation produces chemostactic substances like C3a and C5a to increase vascular permeability, cause smooth muscle contraction, and produce mast cell degranulation
4) MAC is made when C5b initiates the late stage of complement cascade and results in the production of C5b, C6, C7, C8, and polymerized C9, which forms MAC! It is called MAC bc it creates holes in cell membranes of target cells, directly lysing some bacteria and foreign cells
note: *During the process of opsonization, antigens are bound by antibody (i.e. Ig G) and/or complement (C3b) molecules. Phagocytic cells express receptors that bind opsonin molecules. These include the Fc receptors. With the antigen coated in these molecules, binding of the antigen to the phagocyte is greatly enhanced. Most phagocytic binding cannot occur without opsonization of the antigen.
Which 2 complement proteins are produced as an inflammatory response and increases vascular permeability, causes smooth muscle contraction, and promotes mast cell degranulation?
C3a and C5a
C5b initiates the late stage of the complement cascade, resulting in the production of C5b, C6, C7, C8, and polymerized C9, which forms the MAC. Where does MAC get its name from? aka what does MAC do?
MAC creates holes in cell membranes of target cells, directly lysing some bacteria and foreign cells
What portion of the Ab binds to complement and the antigen in the classical pathway?
Fc portion, and once it binds then it is known as the C1 complex which starts the whole pathway
T/F: immunization can also be called vaccination
FALSE
vaccines are a part of immunization, so vaccines can be said as immunization but not the other way around
What are vaccines made of (generally)?
-killed or attenuated bacteria, virus, or attenuated toxin known as toxoids
-a toxoid is a bacterial toxin whose toxicity has been inactivated by chemicals or heat while the immunogenicity is maintained
What are booster injections?
-additional inoculations introduced to increase immune response- make response faster and stronger
-causes anamnestic (memory) response
What are the 4 categories under immunizations?
1) vaccine
2) booster injections
3) attenuated
4) titer
What does attenuated mean?
-rendered incapable of causing disease (mutated), but is capable of inducing immunity and is still a live organism
-reduced toxicity, is not as lethal
What does titer mean?
-concentration, may be used for describing conc. of Ab or virus
-an Ab titer is a measurement of how much antibody and organism has been produced that recognizes a particular epitope
What is an adjuvant?
-substance that can enhance the immune response to an immunogen, such as a vaccine, while having few if any direct effects when given by itself
-adjuvants may have side effects like fever and inflammation
-adjuvants do not increase immune response, but rather increase immunogenicity
What are the 4 different types/modes of acquiring immunity?
1) natural active immunity
2) artificial active immunity
3) natural passive immunity
4) artificial passive immunity
