chapter 18 study guide 2 Flashcards
aggregation involves the cross-linking of pathogens by antibodies to create large aggregates
Agglutination
An ____ is a pathogen-specific molecular structure that stimulates the activation of adaptive immune defenses. It is unique to a specific pathogen and can trigger both humoral immunity (antibody production) and cellular immunity
antigen
refers to the
adaptive immune system’s ability to target specific pathogens,
Specificity
refers to its ability to quickly respond to pathogens to which it has previously been exposed
memory
An _____(or immunoglobulin) is a glycoprotein produced by B cells that is involved in the body’s defense against pathogens and toxins in the extracellular environment as part of humoral immunity
antibody
macrophages, dendritic cells, and B cells have the ability to present antigens specifically for the purpose of activating T cells; for this reason, these types of cells are sometimes referred to as
antigen-presenting cells (APCs)
programmed controlled cell death)
apoptosis
refers to a weakened strain of a pathogen with decreased virulence achieved through methods such as genetic manipulation (to eliminate key virulence factors) or long-term culturing in an unnatural host or environment (to promote mutations and decrease virulence)
Attenuated
are formed from multipotent hematopoietic stem cells (HSCs) in the bone marrow and follow a
pathway through lymphoid stem cell and lymphoblast
B cell
for naïve mature B cells are membrane-bound monomeric forms of IgD and IgM, consisting of two identical heavy chains and two identical light chains connected by disulfide bonds into a basic “Y” shape.
B-cell receptors (BCRs)
Helper T cells and
regulatory T cells are characterized by the expression of ___ on their surface
CD4
cytotoxic T cells are
characterized by the expression of ___.
CD8
are the primary effector cells for cellular immunity. They recognize and target cells that have been infected
by intracellular pathogens, destroying infected cells along with the pathogens inside
cytotoxic
T cells
The two types of helper T cells are relatively short-lived _____, meaning that they
perform various functions of the immediate immune response
effector cells
an ____ is a smaller exposed region on the surface of antigens that antibodies and T cells recognize and interact with.
epitope
are proteases that enter the pores and induce apoptosis.
granzymes
“Remember” a specific pathogen and mount a strong, rapid secondary response upon re exposure
Memory helper T
cells
is a phenomenon where even susceptible individuals in a population are protected from a disease because there are too few susceptible individuals for the disease to spread effectively. It is not related to an individual’s ability to mount an effective immune response.
herd immunity
adaptive immunity mediated by antibodies produced by B cells
humoral immunity
the ______ is the initial stage of the primary antibody response, lasting approximately 10 days, during which no antibody can be detected in the serum.
lag period (or latent period)
This period is the time required for all the steps of the primary response, including:
Naïve mature B cell binding of antigen with BCRs.
Antigen processing and presentation.
Helper T cell activation.
B cell activation and clonal proliferation.
lag period
However, the role of antigens is not limited to humoral immunity and the
production of antibodies; antigens also play an essential role in stimulating cellular immunity, and for this reason
antigens are sometimes more accurately referred to as?
immunogens
are specialized immune cells involved in adaptive specific immunity, which includes B lymphocytes (B cells) and T lymphocytes (T cells).
lymphocytes
The_____ is a collection of genes coding for MHC molecules found on the surface of all nucleated cells of the body.
major histocompatibility complex (MHC)
involves the binding of certain antibodies (IgG, IgM, or IgA) to epitopes on the surface of pathogens
or toxins, preventing their attachment to cells
Neutralization
refers to the transfer of adaptive
immune defenses from another individual or animal
passive immunity
are antibody factories that secrete large quantities of antibodies
Plasma
cells
is a protein that creates pores in the target cell
Perforin
is a form of artificial immunity that stimulates the adaptive immune defenses by artificially triggering memory cell production, similar to what happens during a primary response. This process allows the individual to mount a strong secondary response upon exposure to the pathogen, without having to experience the initial infection
vaccination
refers to the deliberate inoculation of individuals with infectious material from scabs or pustules of
smallpox victims.
Variolation
Lag period of ~10 days before antibodies appear.
Shorter lag period, reduced to just a few days.
Primary Response:
Secondary Response:
Activation of the adaptive immune defenses is triggered by pathogen-specific molecular structures called _____.
antigens
For this reason antigens are sometimes more accurately referred to as _______
immunogens
Antibodies and T cells do not recognize and interact with an entire antigen but with smaller exposed regions on the surface of antigens called ______.
epitopes
Binds to antigen, neutralizes pathogens, agglutination, and antibody-dependent cell-mediated cytotoxicity
Fab (Fragment of Antigen Binding)
Binds complement factors, assists in opsonization (binding to phagocytic cells)
Fc (Fragment of Crystallization)
Most abundant in blood:
Passed to fetus via placenta:
Most abundant in blood: 80% of serum antibody
IgG
Shape: Y-shaped
Chains:
Light Chains: 2
Heavy Chains: 2
binding sites : 2
antibody strucutre
Found in mucus, tears, saliva, and breast milk:
Protects mucous membranes by trapping pathogens
IgA
First antibody in initial infection:
IgM
Acts as receptor on B cells:
Found only in trace amounts in serum
IgD
Effective against large parasites
IgE
Involved in allergic reactions:
IgE
Helper T cells and
regulatory T cells are characterized by the expression of ____on their surface, whereas cytotoxic T cells are
characterized by the expression of ___.
CD 4
CD 8
A single T cell expresses TCRs that are specific to only one unique ____.
epitope
Which comes first: the TCR or the antigen?
TCR
are short-lived and carry out the immediate functions of the immune response, such as activating other immune cells or directing immune processes.
Effector cells (e.g., TH1 and TH2 cells)
are long-lived and remain in the body to “remember” specific antigens. They enable a faster and stronger immune response during subsequent exposures to the same pathogen.
Memory cells
Why is the formation of memory cells important to adaptive immunity?
long term immunity
Binding to the infected cell via their TCR recognizing the antigen-MHC I complex.
Releasing perforin, which creates pores in the target cell membrane.
Delivering granzymes, proteases that enter the cell through the pores and trigger apoptosis (programmed cell death).
how cytotoxic cells kill
Cells infected with viruses or other intracellular pathogens.
Cancerous or tumor cells displaying abnormal antigens.
Foreign cells, such as those from a transplanted organ,
cytotoxic cell targets
A ______ is a massive, uncontrolled release of cytokines caused by the excessive activation of the immune system, such as through superantigens
cytokine storm
_________ are dangerous because they cause severe systemic inflammation, leading to:
A dangerous drop in blood pressure (shock).
Multi-organ failure.
Potential death due to overwhelming immune and inflammatory responses.
cytokine storms
A ____ is a differentiated B cell that functions as an antibody factory. It secretes large quantities of antibodies specific to the antigen that triggered the B cell’s activation.
plasma cell
In a _____, this lag period is approximately 10 days and involves:
Antigen recognition by naïve B cells.
Antigen processing and presentation to helper T cells.
Helper T cell activation.
B cell activation, clonal proliferation, and differentiation into plasma cells.
primary response
in a ____, the lag period is significantly shorter, typically only a few days, due to the presence of memory B cells that quickly recognize and respond to the antigen
secondary response
Involves activation of an individual’s own immune system to produce antibodies and memory cells.
Results in long-lasting immunity.
Example: Recovery from chickenpox or receiving a vaccine.
Active Immunity:
Involves the transfer of antibodies from another individual or source.
Provides immediate but temporary protection (no memory cells are formed).
Example: Antibodies passed from parent to infant through the placenta or receiving an antitoxin.
passive immunity
Acquired through natural exposure.
Example:
Active: Immune response to an infection.
Passive: Antibodies passed to an infant via breast milk.
natural immunity
Acquired through medical intervention.
Example:
Active: Immunization with vaccines.
Passive: Administration of antibody-containing serum for post-exposure prophylaxis (e.g., rabies).
Artificial Immunity:
