Gullo Exam 1 Flashcards
Antigen Definition?
A substance that interacts specifically with any product of the immune system- not always productively
Pathogen definition?
living organisms (usually) that has the ability to cause disease- often has many potential antigens
Immunogen Definition?
an antigen that is recognized by the immune systems and leads to a productive response
What cell type is the largest proportion of leukocytes?
Neutrophils
Humoral Immunity refers to what broadly?
B Cells and their products (antibodies)
Cell-Mediated Immunity refers to what broadly?
CD8+ and CD4+ T Cells
Cytotoxic and Helper, respectively
Infants and Geriatrics share what in common about immune system?
Both weak immune systems
infants have no adaptive immunity, elderly have no new T cells
Explain Recognition Phase of Adaptive Immunity
involves processing of antigen by macrophages/dendritic cells
along with additional cellular interactions which lead to lymphocyte activation.
Explain Activation phase of Adaptive Immunity
involves proliferation and differentiation of lymphocytes
resulting in the expression of specific humoral and cell mediated immune effector functions.
Explain Effector phase of Adaptive Immunity
interaction of immune effector cells and molecules with antigen resulting in the elimination of antigen at the site of the infection.
Antigenic Determinant / Epitope Definition?
exact area of the recognition by B and T lymphocytes on the antigen
Most common antigen type?
proteins
T Cells can only ‘see’ what type of antigen?
peptides
B Cells can ‘see’ what type of antigens?
Chemicals Nucleic Acids Carbohydrates Lipids Peptides
Immunodominant Epitopes definition?
A single Pathogen can contain hundreds of antigens and a large number of immungens
only a set of them will be immundominant
Immunodominant epitopes are defined as those that dominate over others eliciting immune responses
Cross Reactivity and Penicillin
B-lactam ring of penicillin, cephalosporin, and carbapenems
some patients with a previous drug allergy to penicillin can develop drug allergy to cephalosporin
Penicillin can act as a hapten (non immunogenic) and can interact with RBC surface proteins. The combination of both can lead to the recognition of the new immunogen by B cells
Passive Immunization
Homologous hyper immune globulin (e.g. rabies)
Maternal to fetal transmission
Active Immunization
can be live or inactivated/killed. can be whole-cell, polysaccharides, or a subunit.
Explain Antigenic Sin
This process occurs with pathogens that have frequent variation in their antigen structures such as influenza
Immunodominant epitope dominate the response and often mask the new epitopes that on their own might otherwise elicit a response
Happens can only elicit an immune response when?
only capable of stimulating an immune response when bound to a carrier.
B-Cell Receptors are made up of what?
Membrane Bound Abs
Function of Secreted Abs
Neutralize toxins
Prevent the entry and spread of pathogens
Eliminate microbes
General Structural Properties of Ab
two heavy and two light chains held together by disulfide bonds with a ‘hinge’ region
Light Chains of Ab specific structural properties
constant (C) domain at the carboxyl half of the protein
variable (V) domain at the amino terminal half of the protein
Within the variable domain there are three sections with very high variability from protein to protein. Each section is called a complementarity determining regions (CDR) or hypervariable region.
Heavy Chains of Ab specific structural properties
variable (V) domain at the amino terminal end of the protein
Within the variable domain the heavy chain has 3 CDRs or hypervariable regions.
The remainder of the protein chain is divided into several constant domains
Antigen Bindings occurs where on an Ab
Vh and Vl Domains. CDRs function is to bind Antigens
Where is the hinge region found on an Ab?
H chain
Fab region of Ab structure and function?
consists of one light chain and amino terminal half of
one heavy chain
can bind antigen
Fc fragment of Ab structure and function?
consists of the carboxy terminal half of the 2 H
chains
region responsible for most of the common functions of immunoglobulins
F(ab’)2 fragment of Ab function?
can bind antigen bivalently
Function of Hinge Region
Important in activation of B cells (e.g. need to be cross-linked)
Function of Constant Region
Little genetic variation
Imparts function of antibody to the molecule
Define the isotype (E.g. IgG)
Antibody Affinity definition?
Strength of binding between a single Ab arm and an Ag epitope (dissociation constant)
Antibody Avidity definition?
The overall strength of attachment and is much greater than the affinity of any one antigen-binding site
Ratio of human kappa to lamda isotypes of Ab light chains
2:1 (κ to λ)
Agglutination Definition?
Neutralization can occur in solution (e.g. with toxins) or on the surface of a cell through a process called agglutination
Mechanism of Agglutination?
Agglutination often caused toxin or infected cell to be phagocytized or removed from circulation
Opsonization Definition?
Opsonization is the process of coating a surface with antibody and also often leads to phagocytosis
phagocytosis or removal of antibody bound material happens through what type of event?
happens through receptor mediated event on the phagocyte (FcR)
Antibody Maturation Process Explained
Antibodies change from IgM initially to IgG
Requires recognition of same antigen (from primary to secondary response)
Increased concentration, time to produce Ab, and affinity of Ab to antigen in the secondary response
Happens in normal exposure and vaccination
Xenogeneic
non-human Ab treatment
Chimeric Ab
66% Human Ab treatment
Humanized Ab
90-95% human Ab treatment
Fully Humanized Ab
100% human Ab treatment
Isotype defined how?
defined by epitopes on the constant region (H or L chain) and show no variation by member of the same species
Allotype defined how?
defined by epitopes on the constant region (H or L chain) and show variation by members of the same species
Idiotype defined how?
defined by epitopes on the variable regions (H or L chains) and show variation even within the same individual (Bob’s IgM against Polio and his IgM against Varicella Zoster)
What are Fc Receptors?
receptors for Ig on various cell types