produces proteins that attach to and damage the
cell membrane of cells that the immune response
identifies as nonself.
A key feature of the immune response is
INFLAMMATION, the process by which the body
increases the ability of PLASMA, the liquid compo-
nent of blood, to seep into the tissues (interstitial
spaces). HISTAMINEand PROSTAGLANDINSare the pri-
mary agents of the inflammatory response.
Inflammation floods the tissues with immune
molecules to extend the immune response beyond
the blood and the LY M P H. Inflammation also serves
to contain the infection, keeping it from spreading
beyond its point of origin to other areas of the
body.
For further discussion of the immune response
within the context of the structures and functions
of the immune system, please see the overview
section “The Immune System and Allergies.”
See also ALLERGEN; ECHINACEA; GOLDENSEAL;
HUMAN LEUKOCYTE ANTIGENS(HLAS); HYPERSENSITIVITY
REACTION; MACROPHAGE; MAJOR HISTOCOMPATIBILITY
COMPLEX (MHC); MAST CELL; MONOCYTE; NATURAL
KILLER(NK) CELLS; PHAGOCYTOSIS.
immune system The structures, substances, and
processes that protect the body from INFECTION.
These include organs, tissues, cells, and molecules.
The immune system functions in close collabora-
tion with the NERVOUS SYSTEMand the endocrine
system.
The main organs and tissues of the immune
system include
- BONE MARROW
- THYMUS
- SPLEEN
- lymph nodes
- BLOOD
- LY M P H
- adenoids and tonsils
- APPENDIX
- MUCOSA-ASSOCIATED LYMPHOID TISSUE(MALT)
- SKIN
- tears
- saliva
The primary cells of the immune system
include- B-cell lymphocytes (PLASMAcells, memory B-
cells) - T-cell lymphocytes (helper T-cells, cytotoxic T-
cells, memory T-cells, suppressor T-cells) - granulocytes (neutrophils, eosinophils, and
basophils) - macrophages and dendritic cells
- mast cells
- monocytes
- M cells
- natural killer (NK) cells
Key molecules of the immune system include- HUMAN LEUKOCYTE ANTIGENS(HLAS)
- complement factors
- CLUSTERS OF DIFFERENTIATION
- IMMUNOGLOBIN
- antigens
- antibodies
- PROSTAGLANDINS
- HISTAMINE
- LEUKOTRIENES
- CYTOKINES(CHEMOKINES, INTERLEUKINS, MONOKINES,
INTERFERONS, LYMPHOKINES, COLONY-STIMULATING
FACTORS [CSFS], and TUMOR NECROSIS FACTORS
[TNFS])
For further discussion of the structures and
functions of the immune system, please see the
overview section “The Immune System and Aller-
gies.”
See also ANTIBODY; ANTIGEN; ANTIBODY-MEDIATED
IMMUNITY; B-CELL LYMPHOCYTE; CELL-MEDIATED IMMU-
NITY; COMPLEMENT CASCADE; GRANULOCYTE; IMMUNE
RESPONSE; LYMPH NODE; LYMPHOCYTE; MACROPHAGE;
MAJOR HISTOCOMPATIBILITY COMPLEX(MHC); MONOCYTE;
NATURAL KILLER(NK) CELL; PSYCHONEUROIMMUNOLOGY;
T-CELL LYMPHOCYTE.immunity An established base of protection
against INFECTION. Immunity may be innate, pas-immunity 273