Transcript FIB KC Lymphocytes-Immunity

Lymphocytes and Immunity
Clinical Pathology
Ms. Canga
Reading Assignment
A&P book: pp. 237 – 246
 Lab Pro book: pp. 45, & 48-49

◦ (There are some very helpful pictures on
these pages as well!)
Lymphocytes…
…are the predominant WBC in ___________ and
___________.
…are the only WBC with no _________________
capabilities.
…can constantly recirculate between ____________ and
____________.
…may survive for _________ or even ____________.
…cannot be differentiated __________________.
…can cause __________________.
…are predominantly found in _________ and other
tissues. Only ~___% of population are in
__________________.
Lymphocytes
Normal Ranges: 1,000 – 4,800/ in canines and
1,500 – 7,000/µL in felines
 WBC originates from PPSCs in bone marrow
 Immature lymphocytes are processed in the
central ________________ organs:

◦ _______________
◦ _____________________
◦ ____________ (gut-associated lymph tissue)
Lymphocytes
 Mature
lymphocytes live in the
peripheral lymphoid organs
◦ Lymph nodes
◦ _____________
◦ Bone marrow
◦ GALT
◦ _____________
◦ _____________
Fact: The _______________ is the
largest lymphoid organ in the
body.
Lymphocytes in Circulation
 The
lymphocytes in circulation can be
either:
◦ _____________ lymphocytes
 Large lymphocytes are thought to be less mature
 Have more _________________ that is sky blue
 Gradually develop into small lymphocytes
◦ ______________ lymphocytes
 _________________ lymphocytes
 Very little sky blue cytoplasm usually on one side
 May look like a _____________ with no cytoplasm
at all!
Small Lymphocyte
Large Lymphocyte
“Reactive or “Atypical” Lymphocytes
…may have ________________ granules in the
cytoplasm
…may have an abnormally shaped _____________.
(It may look like a monocyte’s nucleus)
…often have larger percentage of ______________
that is very __________________.
…may be normal in some _____________
lymphocytes (granules present)
…are often associated with chronic antigenic
stimulation
(common with Canine ____________________)
Lymphocytes at a Glance
Three Types of Lymphocytes
 _____
– Lymphocytes
 _____ – Lymphocytes
 _____ Cells
T - Lymphocytes

Called T – Cells
◦ Processed in __________ before going to periperal
tissues.
◦ In thymus, they are “pre-T cells” called
__________________
 Multiply rapidly
 Leave thymus and travel to specific zones in lymph nodes and
spleen
 Once they leave the thymus, they are functioning, adult T - cells
◦ T-cells are involved in cellular _____________ and
activation of ______-lymphocytes.
◦ Most lymphocytes in circulation are ____ - Lymphocytes
B - Lymphocytes

Also called B – Cells
◦ Processed in bone marrow and other lymph tissue
referred to as “__________ equivalent”
◦ _______________ producing lymphocytes, that are
involved in ___________ immunity. (AntigenAntibody complex)
 We will discuss this in detail later
Bursa of Fabricius
B – Lymphocytes & Humoral Immunity

Use a “lock and key” type mechanism to fight
foreign invaders.
◦ Each B-lymphocyte is pre-programmed to produce only
______ specific ____________ against one specific
________________.
◦ Cell surface has thousands of ________________
against that specific antigen.
◦ Each antigen has a unique shape on it’s surface called an
_______________.
◦ When antigen binds with B-cell,
__________ -_______________complex is formed.
Antigen – Antibody Complexes
1
2
3
Epitope
4
B- Lymphocytes & Humoral Immunity
Specific B-cells are _____-_______________
to recognize specific antigens.
 ONLY these B-cells will undergo mitotic,
_____________ transformation into
________ cells and begin producing antibodies
against invaders.
 All other B-cells are _______________.
 Potential for over 100 trillion antibodies
produced by the body!

Plasma Cells
Can ____________, store and ___________
antibodies known as immunoglobulins. (More
on this with immunity)
 Found in any ___________ of body
 Most numerous in tissues constantly forming
antibodies: spleen, lymph nodes
 Rare in _______________ blood.

Natural Killer Cells

Called NK cells
◦ Neither ___ nor ___ lymphocytes
◦ Do not require _______________ by an antigen
◦ Have the ability to kill some types of __________
cells and cells infected with various ___________.
◦ Must come in ____________ contact with cells in
order to destroy them.
Lymphocytosis
Physiologic: due to _______________ release.
 Common in chronic __________________.
 May be caused by ____________ stimulation.
 Seen in later stages of resolving
____________.
 Neoplastic lymphocytosis (___________ and
lymphosarcoma)
 Can be significant enough to cause
________________ .

Lymphopenia
One of the most ____________CBC
abnormalities of sick dogs and cats.
 Associated with __________.
 Immunosuppressive therapy.
 Immunodeficiency syndromes.
 Acute _________ infections
 Can be significant enough to cause
____________________, especially in
_______________.

The Immune System

Function: To protect animal from damage/disease.
◦ Recognize “______” from “_________________”
◦ Destroy “______________”
Mechanisms of Destruction
1. ___________________
2. _________(cell membrane)
3. ___________________
4. ___________________
2 Types of Immunity

_________________ immunity
◦ _______ and _______ lines of defense for
the body.

_______________immunity
◦ _______ line of defense for the body
Non-Specific Immunity

First Line of Defense:
◦ _____________ barriers: _________, mucous
membranes, etc…
 Provide protection by ____________________
microorganisms from entering body.
◦ ______________barriers: Hcl acid of gastric
mucosa
 Destroy microorganisms that may be ingested.
Non-Specific Immunity

Second Line of Defense
◦
◦
◦
◦
◦
______________________ Response
______________________ (neutrophils, MPS)
________Cells
__________________
__________________
Nonspecific Immunity (2nd line of defense)

Inflammation
◦ ____________ damage is caused when
microorganisms enter the body.
◦ Damage causes release of _______________
factors from cells
 One example of chemotactic factor released is from mast
cells. (_______________ of tissue)
 What is released by mast cells/Basophils?
Inflammatory Response
Inflammation continued
Nonspecific Immunity: Phagocytosis
Usually involves ________________,
_______________ and tissue
____________________.
 __________________ initiates the WBC’s
death.
 Accumulation of dead WBCs around site
forms ________.

Nonspecific Immunity: NK Cells
…are not __-Lymphocytes or __-Lymphocytes.
…do not have to be ___________ by a specific
antigen.
…can kill some types of __________ and tumor
cells.
…can kill some cells infected with particular
__________.
…must come in ___________ contact with cell
before destroying it.
Nonspecific Immunity: Interferon
…is a _____________ produced by a cell after
it has been infected by a virus. That cell then
dies.
…responds rapidly, entering other cells to inhibit
further development and spread of the virus.
Overview of Interferon Production
Nonspecific Immunity: Complement
…refers to a group of inactive
______________ in plasma.
…are activated by attachment of antibody to
antigen.
…activated enzymes adhere to complement
______________ sites on antigens.
-Each plasma enzyme that attaches, causes
the activation of another and another, creating a
chain reaction until all attachment sites are full.
_______________________ fixation - process by
which complement enzymes arrange into doughnut formation on antigen
surface, create a hole, allowing sodium and water to enter cell and cause it
to swell and burst.
Complement Fixation

As each binding site is
filled, fragments break off
and attach to the
membrane causing the
perforations that
eventually lyse the cell.
Specific Immunity
The _______ line of defense
Primarily involves lymphocytes (__ and __ cells).
Includes _____________ and ___________
Immunity
 Properties of all specific immune responses:
1. Response will be initiated only ________ the
antigen enters the body.
2. Response will be aimed specifically against the
_______________ present
3. If the antigen enters the body a second time, there
will be a ______________ of the antigen and the
immune response will occur more quickly.
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Cell-Mediated, Specific Immunity


A function of __-cell that attaches to the antigen
site.
Tissue __________________ MUST have
ingested antigen and presented its ____________
on its own membrane.
◦ T-cell attaches and becomes a _____________T-cell.


Sensitized T-cell divides many times, _________
itself, and forms either ____________T-cell (Tc),
a ____________T-cell (Th), or a
______________T-cell (Ts)
_____________________ like lymphotoxin are
secreted at the site of infection and quickly kill any
cell it attacks.
The 3 T-Cells

After sensitization by the macrophage, the
lymphocyte can become either a
_____________ T-cell, a __________T-cell,
or a _______________T-cell.
◦ 1) Cytotoxic T-cells (Tc): Are known as
__________ T cells. They attach to antigenic cells
and destroy them but are not
_________________ themselves.
The 3 T-cells

2) __________ T-cells (Th): Are the most numerous of
the T cells. They help the immune response by
secreting additional _________________ into
surrounding tissue.
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Cytokines can increase activation of ___-cells, ____ cells, or
_____ cells.
___________________ is a cytokine that stimulates activity
of all other T cells
________________________________________: is a
cytokine that attracts tissue macrophages to the area via
_______________________ and increases the rate of
phagocytosis. (This then, presents more epitopes to the Tc
cells!)
The 3 T-cells
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3) _________________ T cells (Ts): Operate
by ______________ feedback
◦ They ___________ helper T-cells and cytotoxic Tcells.
◦ They ______________ B-cells from transforming
into plasma cells.
◦ Help to control cell-mediated and humoral immune
responses as infection _______________.
Additional info on Cell-Mediated Immunity
T-cells leave the lymphoid tissue and
_______________ through blood and
lymph.
 B-cells usually stay in _______________
tissue and send out antibodies found in
blood.

◦ Because of this, most lymphocytes in peripheral
blood are __-cells.
◦ If a blood smear is made and both B and T cells
are present, they will appear ______________.
Humoral Immunity
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Is a function of __-Lymphocytes
B-cells, activated by an ___________________________ complex (lock and key system),
produce ___________ cells that secrete
_________________ into the plasma.
B-cells and _____________ cells usually stay in
lymphoid tissue.
_________________________ (antibodies)
circulate in bloodstream (in the ____________),
destroying antigens instead of adhering to cells’
membranes.
Antibodies: aka - Immunoglobulins

_______ types of antibodies (immunoglobulins)
have been identified:
◦ IgG, IgM, IgA, IgE and IgD

Fact: IgG is present in
the greatest quantity of
all the immunoglobulins
When an antibody attaches to an antigen:
◦ Antigens may be _________________ into
harmless substances.
◦ Antigens may be _______________________ and
then phagocytized by macrophages.
◦ _______________________ system may be
activated
The 5 Immunoglobulins

1) _______ : Is made during the bodies
__________ exposure to an antigen.
◦ Is the first immunoglobulin made by
_____________.
◦ Production is relatively _________, so illness may
result before production of IgG is complete.

2) ________: Is made when the animal has been
exposed to an antigen for an _____________
period of time
◦ Is made upon ________ exposure to an antigen.
◦ Production is __________ than IgG, so illness is less
likely.
The 5 Immunoglobulins

3) ________: Plays an important role in
preventing disease entering through
____________ or GI tract.
◦ Can leave the __________ and enter tissue
fluids.
4) ________: Is associated with
_____________ responses.
 5) ________: Function is ____________
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Memory Cells
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Both ___-cells and ___-cells are capable of
becoming Memory Cells
Not all activated lymphocytes become immediately
involved in the immune response.
Memory cells wait for a ___________ infection of
the same ____________ that triggered their
formation.
◦ May ____________ in blood or wait in
________nodes.
◦ Some can live for a few _______; others for several
___________.

Second exposure = more ________ & greater
degree of response to antigen than the
__________ exposure.