Kendall Gray
kmg@uw.edu
Microbiology 301
October 29, 2012
Immunol ogy I: Innate Immunity
I.
First-line defenses (Figs. 14.1–14.4)
II.
Immune cells
A.
Leukocytes (Fig. 14.5, Table 14.1)
1. Granulocytes
2. Macrophages and dendritic cells
3. Lymphocytes
B.
Phagocytosis (Fig. 14.13)
C.
Pattern recognition receptors (Figs. 14.7, 14.8)
III.
The complement system (Fig. 14.10, 14.12)
IV.
The inflammatory response (Fig. 14.14)
V.
Interferons (Fig 14.9)
Gl os sa ry o f Im munol o gy Te rm s
Acquired immunity
The set of defenses that are developed in direct response to the diverse
antigens encountered over a lifetime; sometimes divided into two categories
of the humoral immunity and cell-mediated immunity.
Antibodies
Glycoproteins that bind specifically to a unique antigen; also known as
immunoglobulins.
Antigens
The foreign materials or molecules to which the immune system responds.
Apoptosis
The programmed developmental response leading to the degeneration and
death of specific host cells.
Autoimmune disease
Disease produced as a result of an immune response against one's own
tissues.
B cells
Lymphocytes that produce antibodies. Activated B cells can differentiate into
plasma cells or memory cells.
B cell receptors
Immunoglobulins that remain associated with the cytoplasmic membrane of B
cells.
Cell-mediated immunity
The set of acquired immune responses that involve the action of T cells.
CD proteins
"Cluster of Differentiation" proteins on the surface of T cells that recognize
antigen presentation complexes involving MHC proteins. CD 4 is found on TH
cells and recognizes MHC II presentation complexes. CD 8 is found on T C cells
and recognizes MHC I presentation complexes.
Complement
The set of serum proteins involved in innate immunity. Complement proteins
participate in inflammation, foreign cell lysis, and opsonization.
Co-stimulatory molecules
Surface proteins synthesized by dendritic cells in response to the activation
of their Toll-like receptors. Co-stimulatory molecules are required for the
activation of T cells.
Cytokines
Low molecular weight proteins produced and released by cells to serve as
signaling molecules that affect the behavior of adjacent cells.
Dendritic cells
Leukocytes responsible for collecting and presenting foreign antigens in order
to activate T cells. Dendritic cells provide a link between innate and acquired
immunity.
Epitope
The specific portion of an antigen that is recognized and bound by an
antibody.
Granulocytes
Phagocytic leukocytes that are part of the innate immune response to
infection. Granulocytes are the most abundant class of leukocytes found
circulating in the blood.
Hematopoiesis
The developmental process beginning with undifferentiated stem cells in the
bone marrow that gives rise to all of the diverse types of blood cells.
Humoral immunity
The set of defenses mediated by B cells against free (extracellular) antigens;
commonly referred to as the antibody response.
Immunity
The body's system of defenses against foreign and/or infectious agents;
frequently divided into the two categories of innate immunity and acquired
immunity.
Immunoglobulins
Glycoproteins that bind specifically to a unique antigen; also known as
antibodies.
Inflammation
The innate immune response to physical injury, characterized by swelling,
heat, redness, pain, and accumulation of phagocytic leukocytes in the
affected area.
Innate immunity
The general (non-specific) set of defenses that are present at birth and
change little over a lifetime.
Interferons
A group of cytokines that induce cells to block protein synthesis following
viral infection, thus leading to apoptosis of the infected cells.
Leukocytes
"White blood cells" that are derived from multiple developmental pathways
during hematopoiesis; leukocytes include the granulocytes, macrophages,
dendritic cells, and lymphocytes.
Lymphocytes
Leukocytes that typically reside in the lymph nodes. Lymphocytes include B
cells and T cells.
Macrophages
Phagocytic leukocytes that play a role in both innate immunity and cellmediated immunity.
Memory cells
Long-lived derivatives of activated lymphocytes that persist in the body
following an immune response. Memory cells are responsible for lifelong
immunity to a particular antigen.
MHC proteins
"Major Histocompatibility Complex" proteins that are found on the surfaces of
cells and used to present antigens to T cells. MHC I presents endogenous
antigen to T C cells, while MHC II presents exogenous antigen to T H cells.
Normal microbiota
The group of microorganisms that colonizes body surfaces but does not
typically cause disease; also known as the "normal flora".
Opsonization
The process of coating a particle's surface with host-derived proteins to make
it more susceptible to phagocytosis.
Pattern recognition receptors
Host cell proteins that recognize and bind to specific types of foreign
molecules such as peptidoglycan or double-stranded RNA. Pattern recognition
receptors allow host cells to detect infection and/or cell damage and to
activate the innate immune response by releasing cytokines.
Phagocytosis
The process by which certain leukocytes ingest particulate matter by
engulfing it within a membrane-bound vesicle called a phagosome.
Plasma cells
Short-lived derivatives of activated B cells that produce and secrete large
amounts of antibodies.
T cells
Lymphocytes that play a central role in cell-mediated immunity. T cells are
classified according to their function as either T C or T H cells.
TC cells
"Cytotoxic" T cells whose function is to induce apoptosis in cells that display
foreign antigens.
TH cells
"Helper" T cells whose function is to activate B cells and macrophages in
response to the presentation of foreign antigens.
Toll-like receptors
A group of surface-associated pattern recognition receptors found on diverse
cells in the body.