Antigens & MHC Flashcards
Macromolecules capable of triggering an ____________ immune response by inducing the formation of antibodies or ______________ in an immunocompetent host
IMMUNOGENS
adaptive
sensitized T cells
A substance that reacts with antibody or sensitized T cells but (may/may not) be able to evoke an immune response
ANTIGEN
may not
T/F: All immunogens are antigens but not all antigens are immunogens
T
The nature of the immunogen itself
All immunogens are antigens but not all antigens are immunogens
_________ of MHC molecules that must combine with an __________ before T cells are able to respond
Genetic coding
immunogen
Immunogen processing and presentation
All immunogens are antigens but not all antigens are immunogens
FACTORS INFLUENCING IMMUNE RESPONSE
Age
Overall Health
Dose
Route of Inoculation
Genetic Capacity
Older individuals are more likely to have a (increased/decreased) response to antigenic stimulation
AGE
decreased
______ do not fully respond to immunogens, because their immune systems are not completely developed
AGE
Neonates
Individuals who are ________, __________, or ________ are less likely to mount a successful immune response
OVERALL HEALTH
malnourished
fatigued
stressed
A ____________, allows the innate immune response to take care of small amounts of pathogens and leave the ____________ response for pathogens that are present in large numbers
DOSE
threshold dose
adaptive
Include ________(into a vein), ____________ (into the skin), ____________ (beneath the skin), and _______________
ROUTE OF INOCULATION
intravenous
intradermal
subcutaneous
oral administration
Linked to the _____ and to the receptors generated during T and B lymphocyte development
GENETIC CAPACITY
MHC
Enumerate the traits of immunogens
- Macromolecular size
- Chemical composition and molecular complexity
- Foreignness
- The ability to be processed and presented with MHC molecules
Molecular weight of at least ___________ to be recognized by the immune system
MACROMOLECULAR SIZE
10,000
and the best immunogens typically have a molecular weight of over _________________
MACROMOLECULAR SIZE
100,000 daltons
The rule of thumb is that the (greater/smaller) the molecular weight, the more potent the molecule is as an immunogen
MACROMOLECULAR SIZE
greater
__________ and ____________ are the best immunogens (amino acids)
CHEMICAL COMPOSITION AND MOLECULAR COMPLEXITY
Proteins
Polysaccharides
______ recognize structures that project from the external surfaces of macromolecules
CHEMICAL COMPOSITION AND MOLECULAR COMPLEXITY
B cells
Proteins have ___________ that also stimulate T cells, which is essential to generating T-cell help in antibody production
CHEMICAL COMPOSITION AND MOLECULAR COMPLEXITY
epitopes
T/F: Carbohydrates are somewhat less immunogenic than protein - __________, or ___________
True
glycolipids
glycoproteins
Example of glycolipids
A, B, and H blood group antigens
Example of glycoproteins
Rh and Lewis antigens
Pure ________ and _________ are not immunogenic by themselves
nucleic acids
lipids
Pure nucleic acids and lipids are not immunogenic by themselves, although a response can be generated when they are attached to a suitable carrier molecule (______________)
DNA protein complex
Being able to distinguish between self and non-self,
Foreignness
T/F: those substances recognized as non- self are NOT immunogenic
F; they are immunogenic
Involves ______________ to create small peptides or pieces that can be complexed to MHC molecules to present to ______________
THE ABILITY TO BE PROCESSED AND PRESENTED WITH MHC MOLECULES
enzymatic digestion
responsive lymphocytes
Determinant site
EPITOPE
Molecular shapes or configurations that are recognized by __________ , may be repeating copies, or they may have differing specificities
EPITOPE
B or T cells
Linear or conformational
EPITOPE
Surface antibody on B cells may react with both________ and ____________ epitopes present on the surface of an immunogen
EPITOPE RECOGNITION BY B CELLS
linear
conformational
Surface antibody on B cells may react with both________ and ____________ epitopes present on the surface of an immunogen
EPITOPE RECOGNITION BY B CELLS
linear
conformational
T cells recognize an epitope only as a part of a complex formed with _________ on the surface of an _________________
EPITOPE RECOGNITION BY T-CELLS
MHC proteins
antigen-presenting cell
Non-immunogenic materials that, when combined with a carrier, create new antigenic determinants
HAPTENS
May be complexed artificially with carrier molecules in a _____________, or this may occur naturally within a host and set off an ______________
HAPTENS
laboratory setting
immune response
Antigens that belong to the host
AUTOANTIGENS
These do not evoke an immune response under normal circumstances
AUTOANTIGENS
From other members of the host’s species
ALLOANTIGENS
Capable of eliciting an immune response
ALLOANTIGENS
Alloantigens are important to consider in _________________ and in __________________
tissue transplantation
blood transfusions
From other species, such as other animals, plants, or microorganisms
HETEROANTIGENS
Are heteroantigens that exist in unrelated plants or animals but are either identical or closely related in structure so that antibody to one will cross-react with an antigen of the other
HETEROPHILE ANTIGENS
A substance administered with an immunogen that increases the immune response;
ADJUVANTS
acts by producing a ______________ that attracts a large number of immune system cells to the injection site
ADJUVANTS
local inflammatory response
_________________ are the only ones approved for clinical use in the United States
ADJUVANTS
Aluminum salts
these are used to complex with the immunogen to (decrease/increase) its size and to prevent a rapid escape from the tissues
ALUMINUM SALTS
increase
It must be injected into the muscle to work
Aluminum salts
The ____________ vaccination is an example of using this type of adjuvant
ALUMINUM SALTS
hepatitis B
are thought to enhance the immune response by prolonging the existence of immunogen in the area,
ADJUVANTS
(decreasing/increasing) the effective size of the immunogen, and (increasing/decreasing) the number of __________ involved in antigen processing
ADJUVANTS
Increasing
increasing
macrphage
MAJOR HISTOCOMPATIBILITY COMPLEX MOLECULES formerly referred to as _____________________________
human leukocyte antigen (HLA)-Dausset
They determine whether transplanted tissue is histocompatible and thus accepted or recognized as foreign and rejected
MAJOR HISTOCOMPATIBILITY COMPLEX MOLECULES
MAJOR HISTOCOMPATIBILITY COMPLEX MOLECULES
Main function: Bring _______ to the ______________ for recognition by T cells, because T-cell activation will occur only when antigen is combined with ____________
antigen
cell surface
MHC molecules
T/F: MHC molecules are NOT relevant
FALSE; they ARE relevant
MHC molecules are relevant because they may be involved in _________________, ____________________, and _________________
transfusion reactions
graft rejection
autoimmune diseases
Genes controlling ____________ of these molecules are actually a system of genes known as the major histocompatibility complex
expression
Genes coding for the MHC molecules in humans are found on the short arm of chromosome __ and are divided into _____ categories or classes
chromosome 6
three
molecules are coded for at three different locations or loci, termed A, B, and C
CLASS I
genes are situated in the __ region, and there are several different loci known as __, __, and __
CLASS II
D
DR
DQ
DP
There is a gene that codes for the alpha chain and one or more genes that code for the beta chain
CLASS II
coded between the class I and class II regions on chromosome,
CLASS III
codes for complement proteins and cytokines such as _________________________
CLASS III
tumor necrosis factor
Expressed on all nucleated cells
Structure of Class I
Highest on ______________ and low or undetected on_________________, _____________, _____________, and _________
CLASS I
lymphocytes
liver hepatocytes
neural cells
muscle cells
sperm
CLASS I
The alpha chain has a molecular weight of ____________
45,000
CLASS I
A lighter chain associated with it, called a ________________, has a molecular weight of ___________ (alpha chain domains – a1, a2, a3)
beta2- microglobulin
12,000
reacts with CD8 on cytotoxic T cells
a3
Found primarily on antigen-presenting cells, which include _____________, __________, _____________, and ___________
CLASS II
B lymphocytes
monocytes
macrophages
dendritic cells
CLASS II
_____ is expressed at the highest level, as it accounts for about _____ of all the class II molecules on a particular cell
DR
one-half
CLASS II
The DR gene is the most highly (dimorphic/ polymorphic) as ___ different alleles are known at this time
polymorphic
18
CLASS II
Both the chain, with a molecular weight of __________, and the chain, with a molecular weight of__________, are anchored to the __________________
33,000
27,000
cell membrane
Role of MHC Class I and Class II
To bind __________ within cells and transport them to the ___________, where T cells can recognize them in the phenomenon known as _____________
peptides
plasma membrane
antigen presentation
Mainly present peptides that have been synthesized within the cell to_______ (cytotoxic) T cells
CLASS I
CD8
The watchdogs of viral, tumor, and certain parasitic antigens that are synthesized within the cell
CLASS I
Display of hundreds of __________ molecules complexed to antigen allows CD8+T cells to continuously check cell surfaces for the presence of ____________
CLASS I
class I
non-self-antigens
If it recognizes an antigen as being foreign, the CD8+T cell produces _______ that causes ___________ of the entire cell
CLASS I
cytokines
lysis
Present antigen to CD4 (helper) T cells
CLASS II
Mainly bind ________________ proteins – those taken into the cell from the outside and degraded
CLASS II
exogenous
Stimulate ___________ in the case of bacterial infections or the presence of other material that is endocytosed by the cell
CLASS II
CD4 T cells
On the cell surface, ___________ molecules are responsible for forming a _____________ that occurs between ________, ____________, and an _______________________
CLASS II
Class II
trimolecular complex
antigen
class II molecule
appropriate T-cell receptor
If binding occurs with a T-cell receptor on a CD4+T cell, the T helper cell recruits and triggers a _______________ resulting in ________________
CLASS II
B-cell response
Antibody formation
