Summary of
"Classic Toxicology:
Chemically-Induced Immune Response Explained
From Our Toxic Times,
(April 1999, Vol 10, No 4).
by Dr. Patrick Williams
of Benchmark Genetics
Phone: 507- 645-2378
In "Classic Toxicology: Chemically-Induced Immune
Response Explained,"
Dr. Patrick Williams provides an explanation, following the traditional
toxicological model, of how the immune system reacts with toxic
chemicals.
Dr. Patrick Williams describes:
Innate Immunity - the
body’s physical and chemical barriers; blood proteins;
phagocytic
macrophages, neutrophils, and natural killer cells.
and Acquired Immunity - a specific
immune response to each foreign agent.
Also, Dr. Patrick Williams discusses Chemical Irritants,
Toxicants,
Allergens and Hypersensitivity
Chemical Irritants and Toxicants
"Toxic effects are
not produced by a chemical agent unless that
agent or its metabolites
reach susceptible cells tissues, or organs
within the body. In
addition, the concentration and longevity of
the chemical in the
body are critically important to the production
of a toxic effect
... and the susceptibility of the body.
As in the case of
chemical irritants, cellular and tissue
toxicity
results in an
inflammatory response. If this occurs on the external
surface, redness,
swelling, heat, and pain will be observed.
These same indications
of inflammation occur inside the body
as well."
Chemical Allergy
"Chemical allergy is an
immunologically mediated adverse reaction
resulting from previous
exposure (sensitisation) to a specific chemical
or structurally similar
one (hypersensitivity). Most chemicals and their
metabolic products
are not large enough to be recognized by the immune
system as a foreign
substance."
"However, when a chemical
binds with a "self" protein (called a hapten)
it forms an
antigen and can now be recognized by the immune system ...
"This
hapten-protein complex (antigen) is
then capable of stimulating
the formation of
antibodies, which occurs over a 7-14 day period.
This process is called
sensitization."
Hypersensitivity
can be classified into four types
on the basis of immune
mechanisms and mediator molecules (this is a simplification):
TYPE 1 -
Immediate Hypersensitivity - typically mediated
by IgE
(eg
isocyanates).
TYPE 2 -
Antibody-Mediated Cytotoxic Hypersensitivity -
antibodies
against haptens bound to cell surfaces (eg heavy metals).
TYPE 3 -
Immune Complex Mediated Hypersensitivity - deposition
of antigen-
antibody complexes in various tissues (blood vessels and joints).
TYPE 4 - Cell
Mediated Hypersensitivity - sensitized T cells (typically in skin)
release cytokines in response to a secondary exposure (eg allergic
contact dermatitis which represents a true allergy with minute amounts
of
chemical causing reactions -- distinct from irritant contact dermatitis
where the severity of the reaction is related to the dose applied.
Fifty (50%) of
chemically sensitive patients display Type 4
Hypersensitivity Reactions (Rea, 1992.)
The full article, "Classic Toxicology: Chemically
Induced Immune Response Explained," (and many others on related
topics) is available from:
The Chemical Injury Information
Network (CIIN) and its monthly
magazine,
Our Toxic Times.
To view the extensive index of past issues,
please click here.
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