[DISCUSSION] ADAPTIVE IMMUNITY Flashcards
•Develops as a response to infection
and adapts to the infection
ADAPTIVE
•Potent protective responses are
acquired by experience
•“Specific”
•“Acquired”
Adaptive/ Acquired/ Specific Immunity
•COMPONENTS:
•Lymphocytes and their products
Features of Adaptive Immunity
- Specificity
- Diversity
- Memory
- Clonal expansion
- Specialization
- Self-limitation
- Discrimination of self from /mfechan nonself
• Ensures that distinct antigens elicit specific
responses
- Specificity
• Enables immune system to respond to a large
variety of antigens
- Diversity
• Leads to enhanced responses to repeated
exposures to the same antigens
- Memory
•Increases number of antigen-specific
lymphocytes to keep pace with microbes
- Clonal Expansion
•Generate responses that are optimal for
defense against different types of
microbes
- Specialization
•Allows immune system to respond to newly
encountered antigens
- Self-limitation
•Prevents injury to the host during
responses to foreign antigens
- Discrimination of self from nonself
Types of Acquired Immunity
- Active Immunity
- Passive immunity
- Active Immunity
• Natural Active
• Artificial active
- Passive immunity
• Natural Passive
• Artificial Passive
Onset of immunity ACTIVE
Slow/ acquired gradually (5 – 14 d)
Onset of immunity PASSIVE
Immediate
Duration of effect ACTIVE
Long-term
Duration of effect PASSIVE
Short term
Source ACTIVE
Self
Source PASSIVE
Non-self
Immunizing agent ACTIVE
Antigen
Immunizing agent PASSIVE
Immune serum (Ab’s)
Relative effectiveness ACTIVE
Small
Relative effectiveness PASSIVE
Large
Relative effective dosage
required ACTIVE
Small
Relative effective dosage
required PASSIVE
Large
Route of injection ACTIVE
IM, ID
Route of injection PASSIVE
IV
Function ACTIVE
Prophylactic
Function PASSIVE
Therapeutic, prophylactic
Duality of the immune system
1.Humoral Immunity
- Cell-mediated Immunity
Responding B cell
Naive (virgin) B cell
Memory B cell
Responding B cell
Lag period antigen administration
Time of peak of response
Magnitude of antibody response
Isotype produced
Antigens
Antibody affinity
Cells of Adaptive Immunity
B-CELLS/ B LYMPHOCYTES
T CELLS/ T LYMPHOCYTES
ANTIGEN PRESENTING CELLS
NAÏVE LYMPHOCYTES
EFFECTOR LYMPHOCYTES
MEMORY CELLS
B-CELLS/ B LYMPHOCYTES
- FOLLICULAR B-CELLS
- B-1 CELLS
- MARGINAL ZONE B CELL
T CELLS/ T LYMPHOCYTES
- CD4+ HELPER T-CELLS
- CD8+ CYTOTOXIC T LYMPHOCYTES (CTLs)
- CD4+ REGULATORY T-CELLS
ANTIGEN PRESENTING CELLS
- DENDRITIC CELLS
- MACROPHAGES
- B-CELLS
•cells that produce antibodies
B cells
•were so called because in birds they were
found to mature in an organ called the bursa
of Fabricius
B cells
refers to bone
marrow–derived lymphocytes
B lymphocytes
express surface
antibodies that act as receptors for
specific antigen
Mature B cells
•All antibodies on this cell, irrespective of
the classes or combinations of classes,
have the same antigen specificity.
B cell
•the most numerous type of B
cells in the body
Follicular B cells
•are found in lymphoid tissues
and blood
Follicular B cells
express highly diverse, clonally distributed
sets of antibodies that serve as cell
surface antigen receptors and as the key
secreted effector molecules of adaptive
humoral immunity
/mfecha
Follicular B cells
•give rise to most of the high-affinity
antibodies and memory B cells that protect
people from repeat infections by the same
microbes.
Follicular B cells
•make up a minority of B cells and
produce antibodies with very limited
diversity
B-1 cells
•found mainly in mucosal tissues and
the peritoneal and pleural cavities
B-1 cells
•make up a minority of B cells and
produce antibodies with very
limited diversity
Marginal zone B cells
•present mainly in the spleen
Marginal zone B cells
•mediators of cellular immunity
T Cells
•arise from precursor cells in the bone
marrow, which migrate to and mature in the
thymus
T Cells
required for the full expression
of immunity
T Cells
T cells regulate:
• antibody production
• cellular immune reactions
• killing of altered cells
cells can act as regulatory cells
that modulate the activities of
other T cells, macrophages, or B
cells
T cells
•Regulation can take the form of help
or suppression.
T Cells
mediate cellular immunity reactions
through the production of cytokines
T Cells
promote proliferation and
differentiation of T cells and attract or
activate other elements of the immune
system (i.e., stimulate immune responses)
cytokines
can interact directly with
target cells and destroy virus-
infected cells, foreign tissues, or
tumor cells
T Cells
•As cytotoxic cells, T cells are the major cells
involved in viral, transplantation, and tumor
immunity.
T Cells
