Immuno pathology Flashcards
The recognition or discrimination between the so-called ______ and _____ is the primary role of the immune system. This
recognition of ______ is important to protect against invading microorganisms, chemical agents, or other foreign substances.
“self” and “non-self”
non-self
Elimination of
foreign or non-self of the immune system involves a variety of mechanisms
such as:
1.Inactivation of biologic agents
2.Lysis of foreign cells
3.Agglutination of molecules
4.Precipitation of molecules or cells
5.Phagocytosis of foreign materials
Immune reactions are divided into two broad categories:
Humoral immunity
Cellular immunity
Humoral immunity
•
B-cell lymphocyte mediated via production of antibody
•
Often develops as a response to soluble antigens
•
B cells account for about 20% of circulating lymphocytes
•
Immunoglobulin gene rearrangements allow tremendous diversity of
responses to many antigens
In the diagram of an
immunoglobulin molecule, note
that there are two heavy (H)
chains and two light (L) chains
linked by disulfide bonds. Each
heavy and light chain has a
constant (C) and a variable (V)
region. It is the variable regions
in the Fab portion that react
with a specific antigen and give
rise to the diversity of
immunologic response.
Immunoglobulin can attach via
the Fc portion to a variety of
cells with Fc receptors.
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There are five immunoglobulin classes (isotypes) of antibody
molecules found in serum:
IgG, IgM, IgA, IgE, and IgD.
1. IgA (immunoglobulin A)
2. IgD (immunoglobulin D)
3. IgE (immunoglobulin E)
4. IgG (immunoglobulin G)
5. IgM (immunoglobulin M)
ACTION OF ANTIBODIES
• Agglutinin- antibodies that cause agglutination of cells
• Anti-toxin – neutralizes toxins or poisons
• Lysin – antibodies that cause lysis of cells
• Opsonin – antibodies that present or enhance phagocytosis
• Precipitins - antibodies that cause precipitation
• - antibodies that cause agglutination of cells
Agglutinin
neutralizes toxins or poisons
Anti-toxin
antibodies that cause lysis of cells
Lysin
antibodies that present or enhance phagocytosis
Opsonin
antibodies that cause precipitation
Precipitins
Cellular immunity
•
T-cell lymphocyte mediated
•
CD4+ helper lymphocytes: help B cells make antibody and also help to
generate cytotoxic T cells; participate in delayed hypersensitivity reactions;
account for 60% of peripheral T lymphocytes
•
CD8+ suppressor lymphocytes: are cytotoxic; represent about
30% of circulating T lymphocytes
•
T-cell receptors (TCR) are genetically programmed to recognize
specific antigens and can rearrange their alpha and beta genes to respond to
antigenic stimuli o Macrophages process antigen and present it with class
II HLA to the CD4+ cells o
Cytokines such as interleukin (IL) and
tumor necrosis factor (TNF) are elaborated by activated T cells to enhance
cellular immune reactions
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help B cells make antibody and also help to
generate cytotoxic T cells; participate in delayed hypersensitivity reactions;
account for 60% of peripheral T lymphocytes
CD4+ helper lymphocytes:
: are cytotoxic; represent about
30% of circulating T lymphocytes
CD8+ suppressor lymphocytes
are genetically programmed to recognize
specific antigens and can rearrange their alpha and beta genes to respond to
antigenic stimuli
T-cell receptors (TCR)
Macrophages process antigen and present it with
class II HLA to the CD4+ cells
are elaborated by activated T cells to enhance
cellular immune reactions
Cytokines such as interleukin (IL) and
tumor necrosis factor (TNF)
The reaction of tissues to antigen (AG) is mediated by two cell types:
B LYMPHOCYTES (Bursae-derived)
.
T LYMPHOCYTES (Thymus-derived)
Secretes ________ after conversion to ________
ANTIBODIES
PLASMA CELLS.
- Responsible for cell-mediated immunity. It does not secrete antibodies.
Rather, releases LYMPHOKINES.
T LYMPHOCYTES (Thymus-derived)
T LYMPHOCYTES (Thymus-derived)
- Responsible for cell-mediated immunity. It does not secrete antibodies.
Rather, releases _____________.
LYMPHOKINES
_________________ This is mediated by IgE antibodies bound to mast cells
and basophils that is formed in response to a particular antigen (or allergen).
In this type of hypersensitivity, clinical signs/symptoms occur after the
release of pharmacologically active compounds from mast cells and basophils.
These cells (basophils and mast cells) possess receptors capable of binding the
Fc portion of the IgE molecule. M
TYPE I. IMMEDIATE HYPERSENSITIVITY or ANAPHYLACTIC HYEPRSENSITIVITY
Mast cell and/or basophil degranulation
releases the following pharmacologically and biologically active compounds:
- Histamine
- Leukotrienes
- Eosinophil
chemotactic
factor - Platelet
activating
factor - Kallikrein
- Platelet
aggregating
factor - Kinins
- Serotonins
- Proteolytic substances
AGENTS THAT CAUSE ANAPHYLAXIS is numerous and include:
a.venom or stings of biting insects
b.vaccines
c.variety of drugs
d.food substances
e.blood donors/blood products
Clinical signs can be localized or generalized. Symptoms include:
1.restlessness and excitement
2.facial edema
3.pruritus on affected area
4.salivation
5.lacrimation
6.vomiting
7.diarrhea
8.abdominal pains
9.dyspnea
10.cyanosis
11.shock
12.incoordination
13.convulsions
14.death
In domestic animal species, the symptoms of anaphylaxis vary depending in part to the
distribution of mast cells in the animal body.
-
In DOGS, the
major organ affected is
the ____. Constriction
of hepatic veins due to
concentrations of mast cells result to portal hypertension and visceral pooling
of blood. Therefore, clinical signs in dogs are gastrointestinal rather than
respiratory.
LIVER
-Anaphylaxis in cats (felines) is characterized by _________,_________,_______. Other signs in the cat include _______..
respiratory signs, bronchoconstriction and pulmonary edema
dyspnea, facial itching, salivation, incoordination, collapse, shock and even
death
-
In PIGS and HORSE, anaphylaxis is manifested as
pulmonary emphysema, peribronchiolar edema and edematous hemorrhagic
enterocolitis.
are the presenting signs involving the RUMINANTS anaphylaxis
Systemic hypotension, with dyspnea, urination, defecation and
bloating
Immediate Hypersensitivity Reaction. A, Early reaction (minutes) is characterized by mast cell degranulation and release of pre- formed vasoactive substances that cause vasodilation and increased vascular permeability, resulting in edema of interstitial tissue. B, As the lesion pro- gresses to the late phase (hours), the inflammatory infiltrate is primarily composed of eosinophils and fewer lymphocytes and neutrophils.
Og. 35
TYPE II
HYPERSENSITIVITY (CYTOTOXIC / CYTOLYTIC REACTIONS ) or
AUTOIMMUNITY.
is defined as the immune response against individual’s own tissue antigens.
Autoimmunity
Autoimmunity is defined as the immune response against
This type of reaction can be produced subsequent to:
1.
Complement – dependent reactions
Occur either by direct lysis via the C5-9 (membrane attack complex) or by
opsonization (or enhanced phagocytosis).
Examples: Transfusion reactions from unmatched donor.
Hemolytic disease of the newborn
Thrombocytopenic purpura
2.
Antibody-dependent cell-mediated cytotoxicity (ADCC). In this,
reactions can be produced through antibody dependent cell mediated
cytotoxicity. In this process, antibody attaches to the target antigen through
Fab (fragment antibodybinding) antigen combining sites. The Fc ( fragment
cell-binding) end of the antibody is free to interact with cytotoxic cells having
an Fc receptor such as macrophages, polymorphonuclear cells, and natural
killer lymphocytic cells.
Example:
Autoimmune hemolytic anemia
-
own’s tissue or cell has been recognized as “NON-SELF”
Immune mediated anemia in events of trypanosomosis, babesiosis Drug-induced (penicillins,
aminosalicylates, phenacetin)
Thrombocytopenic
(aminopyrine, phenothiazine,
chloramphenicol
sulfonamide,
phenylbutazone).
Systemic lupus
erythematosus
-
presence of anti-DNA
antibody;
Check pg 37
Pg38 picture
Type IV hypersensitivity is also known as
cell-mediated
hypersensitivity
it is the result of the interaction of T lymphocytes
and the specific antigen to which they have been sensitized
Type IV hypersensitivity
