Transcript Lecture / notes (updated)

The Immune System
The Immune System
First lines of defense:
•Skin
•Mucus
•Stomach acid
•Digestive enzymes
Innate Immunity
•Phagocytic cells
–Leukocytes (“white cells”)
–Lymphocytes (“lymph cells”)
–Macrophages (“big eaters”)
–Natural killer cells (attack
infected or cancerous body cells)
Innate Immunity
Innate Immunity
Innate Immunity
Innate Immunity
Innate Immunity
Innate Immunity
Innate Immunity
Innate Immunity
Innate Immunity
•Inflammation
–Redness and swelling
•Interferon
–Released by infected cells,
signals neighboring cells to
prepare for invasion
Acquired Immunity
•Lymphocytes
–B cells and T cells
•Antibodies
–Immunoglobulins
Acquired Immunity
Antigens are foreign
molecules that elicit
an immune response
Acquired Immunity
Antigens are foreign
molecules that elicit
an immune response.
Acquired Immunity
B cells have antigen receptors
that recognize intact antigens.
B
Acquired Immunity
T cells have antigen receptors
for fragments of antigens.
B
T
Acquired Immunity
Each lymphocyte recognizes
one and only one antigen.
B
T
Acquired Immunity
•Lymphocytes are made in
the bone marrow
•B cells mature in the bone
marrow
•T cells go to the thymus
before maturing.
Acquired Immunity
•Genes in lymphocytes are
randomly, permanently
rearranged to produce over ten
million different antigen
receptors
•The ones that react to “self” are
destroyed.
Acquired Immunity
Two kinds of immune response:
Humoral
Defends against toxins or
pathogens outside of cells
Cell-mediated or cytotoxic
Destroys infected cells, cancer
cells, and transplanted cells
Humoral Immune Response
Here come the germs…
Humoral Immune Response
Here come the germs…
Humoral Immune Response
1. A macrophage or a dendritic
cell engulfs one of the invading
bacteria
Humoral Immune Response
1. A macrophage or a dendritic
cell engulfs one of the invading
bacteria.
Humoral Immune Response
2. The macrophage displays broken
up bits of the antigen bound to a
major histocompatibility complex
(MHC).
Humoral Immune Response
3. A helper T cell recognizes the
antigen fragments and is activated
Humoral Immune Response
3. A helper T cell recognizes the
antigen fragments and is activated
Humoral Immune Response
3. A helper T cell recognizes the
antigen fragments and is activated
Humoral Immune Response
3. A helper T cell recognizes the
antigen fragments and is activated.
Humoral Immune Response
4. A B cell also recognizes the
antigen and binds to it
Humoral Immune Response
4. A B cell also recognizes the
antigen and binds to it
Humoral Immune Response
4. A B cell also recognizes the
antigen and binds to it.
Humoral Immune Response
5. An activated helper T cell binds to
the B cell and secretes cytokines to
activate it
Humoral Immune Response
5. An activated helper T cell binds to
the B cell and secretes cytokines to
activate it
Humoral Immune Response
5. An activated helper T cell binds to
the B cell and secretes cytokines to
activate it
Humoral Immune Response
5. An activated helper T cell binds to
the B cell and secretes cytokines to
activate it
Humoral Immune Response
5. An activated helper T cell binds to
the B cell and secretes cytokines to
activate it
Humoral Immune Response
6. The activated B cell divides
to make two kinds of cells:
Humoral Immune Response
-Plasma cells make antibodies
Humoral Immune Response
Plasma cells (effector cells)
make antibodies
Humoral Immune Response
Memory cells wait for the next
invasion.
Humoral Immune Response
7. Antibodies bind to antigens.
Humoral Immune Response
There are four ways that antibodies work:
Humoral Immune Response
There are four ways that antibodies work:
neutralization
Humoral Immune Response
There are four ways that antibodies work:
neutralization
Humoral Immune Response
There are four ways that antibodies work:
neutralization
Humoral Immune Response
There are four ways that antibodies work:
agglutinization
Humoral Immune Response
There are four ways that antibodies work:
agglutinization
Humoral Immune Response
There are four ways that antibodies work:
agglutinization
Humoral Immune Response
There are four ways that antibodies work:
agglutinization
Humoral Immune Response
There are four ways that antibodies work:
agglutinization
Humoral Immune Response
There are four ways that antibodies work:
compliment fixation
Humoral Immune Response
There are four ways that antibodies work:
compliment fixation
Humoral Immune Response
There are four ways that antibodies work:
compliment fixation
Humoral Immune Response
There are four ways that antibodies work:
compliment fixation
Humoral Immune Response
There are four ways that antibodies work:
compliment fixation
Humoral Immune Response
There are four ways that antibodies work:
compliment fixation
Humoral Immune Response
There are four ways that antibodies work:
compliment fixation
Humoral Immune Response
There are four ways that antibodies work:
compliment fixation
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Humoral Immune Response
There are four ways that antibodies work:
opsonization
Cell Mediated Immune Response
Cell Mediated Immune Response
Here come the germs…
Cell Mediated Immune Response
A cell is infected
Cell Mediated Immune Response
A cell is infected
Cell Mediated Immune Response
1. A cell is infected.
Cell Mediated Immune Response
2. Antigens are displayed on the
cell surface bound to MHC.
Cell Mediated Immune Response
3. A cytotoxic T cell (“killer T
cell”) binds to the antigens
Cell Mediated Immune Response
3. A cytotoxic T cell (“killer T
cell”) binds to the antigens
Cell Mediated Immune Response
3. A cytotoxic T cell (“killer T
cell”) binds to the antigens.
Cell Mediated Immune Response
4. Binding activates the T cell,
which releases lytic enzymes.
Cell Mediated Immune Response
5. Lytic enzymes destroy the cell
(“apoptosis”)
Cell Mediated Immune Response
5. Lytic enzymes destroy the cell
(“apoptosis”)
Cell Mediated Immune Response
6. T cell can now attack other
target cells.
Cell Mediated Immune Response
Cancer cells will also display
antigens that bind with killer T
cells.
Immunity in Health and Disease
Immunity in Health and Disease
Active vs. passive immunity.
Immunity in Health and Disease
Rejection of transplanted tissue
Immunity in Health and Disease
Rejection of transplanted tissue
Graft vs. host reaction.
Immunity in Health and Disease
Allergies
Immunity in Health and Disease
Autoimmune diseases
Immunity in Health and Disease
Immunodeficiency diseases