Lec 3: WBC

What are the 5 types of WBCs?

Neutrophils, eosinophils basophils, lymphocytes, monocytes

What is the main function of WBCs?

Identify and react to foreign substances (immunity) and damage (inflammation) in/to the body

Which WBCs are classified as Granulocytes?

Neutrophils, eosinophils, basophils

Which WBCs are classified as Agranulocytes?

Lymphocytes and monocytes

Non specific, physical and chemical barriers, inflammation

Innate immunity

Specific, humoral (fluid) response, cell mediated response

Acquired immunity

What are examples of physical barriers for innate immunity?

Intact skin, mm

What are examples of chemical barriers for innate immunity?

Tears, saliva, HCl in the stomach

What characterized inflammation?

Pain, swelling, heat, redness, and loss of function

APCs present antigen to B lymphocytes which stimulates antibody production

Humoral (fluid) response

APCs present antigen to T lymphocytes which are stimulates and produce a variety of specific cells

Cell mediated response

What are two types of responses in acquired (specific) immunity?

Humoral (fluid) response and cell mediated response

What are the cellular components of innate immunity?

Neutrophils, NK cells, Interferon, monocytes/macrophages

What are the cellular components of acquired immunity?

B lymphocytes (plasma cells, memory B cells), T lymphocytes (memory T cells, helper T cells, killer T cells suppressor T cells, mediator T cells), monocytes/macrophages

First responders which phagocytize foreign matter and organisms

Neutrophils

Clean up what the neutrophils cannot control.

Phagocytosis of viruses, protozoa, fungi, and other microorganisms

Recognize, process, and present antogen to lymphocytes for removal

Monocytes/macropahges

Direct cell-to-cell contact and lysis of invading of foreign materials

Destroy some tumor cell types

NK cells

Interferon

Released by healthy cells in response to viral invasion to protect against viral entry

Which major cell component of acquired immunity (B lymphocytes or T lymphocytes) contains plasma cells and memory B cells?

B lymphocytes

Which major cell component of acquired immunity contain memory T cells, helper T cells, killer T cells, suppressor T cells, and mediator T cells?

T lymphocytes

Produce specific antibodies to particular antigen

Plasma cells

Survive for months to years and can respond to antigen at a later time and faster

Memory B cells

Assist B lymphocytes in antigen recognition and antibody production

Helper T cells

Control and limit the immune response of all T cells

Suppressor T cells

Which cellular component is in both innate and acquired immunity?

Monocytes/macrophages

How long does it take to upregulate the immune response?

2-3 days

At what point does the immune response peak before declining?

1-2 weeks

What are immunoglobulins?

Antibodies the are considered “gamma” globulins (4 types)

what are the 4 types of antibodies found in animals?

IgG, IgM, IgE, IgA

Most common, comprises 75% of antibodies in the body, found int he blood vessels and tissues

IgG

Large molecule confined to the vasculature, 5% of the total

IgM

Normally 1% of total but usually increases in presence of allergies or parasites

IgE

Normally found on body surfaces, secretions of the skin , the digestive tract, and the respiratory tract, comprised 20% of the total

IgA

Overall picture of the status of the WBCs in the body

Leukogram

Cells being formed in the bone marrow

Proliferation

Mature cells stores in the spleen and bone marrow

Storage

Freely moving in the vessels from where the sample is taken

Circulating

Stuck to or rolling along the vessel walls

Marginal

Various areas of the body where WBCs perform basic functions

Tissue

Increase in the number of WBCs above the normal reference range

Leukocytosis

Abnormally low number of WBCs below the normal reference range

Leukopenia/leukocytopenia

Presence of abnormal WBCs in the circulating blood: usually seen when neoplasia (cancer) is also present

Leukemia

Presence of abnormal WBCs in the circulating blood in the absence of neoplasia

Leukemoid response

What can cause normal physiological changes in the Leukogram?

Excitement, fear, apprehension, or pain, muscular exertion or exercise, stress, digestion, pregnancy, estrus, age, species, post immunization

Mature within the bone marrow in 3-10 days

Migrate to tissues from circulation within 6-7 hours of release form storage pools

Remain in the tissues as needed for 2-3 days

May only last a few hours within tissues in the presence of a disease process

Neutrophils

Immature form, nucleus has no lobes or segments

“Band” or “stab” neutrophil

Drumstick or club-like appendage of the nucleus

Only seen in females

Remnant of an inactivated X chromosome

Barr body

Bluish staining inclusions in the cytoplasm

Remnants of rough ER

Dohle bodies

Nucleus contains more than 5 lobes or segments

Indicates cell has been in circulation for awhile

Hypersegmented neutrophil

Small particles are engulfed and broken down by enzymes in the cytoplasmic granules

Larger particles are broken down via release of enzymatic granules from the cell

Inflammation and phagocytosis

Increased numbers of circulating neutrophils; infection, inflammation (trauma), neoplasia, toxins, physiologic or iatrogenic corticosteroids or epinephrine (stress)

Neutrophilia

Decreased numbers of circulating neutrophils; bone marrow suppression, massive infection, shock

Neutropenia

When rapid loss and increased demand for neutrophils leads to increased production by the bone marrow to keep up with demand in the body

A greater percentage of immature forms is released as a result

Left shift in the leukogram

What is the order of the degree of left shift from slight to extreme?

(Slight 1) bands only

(Moderate 2) metamyelocytes

(Marked 3) myelocytes and promyelocytes

(Extreme 4) myeloblasts

Neutrophilic leukocytosis is present

Immature forms are =/< mature adult forms (segmented neutrophils)

Indicates adequate bone marrow response

Good prognosis

Regenerative left shift

Neutropenic leukopenia

Immature forms>mature adult forms

Bone marrow has not had time or cannot meet demand

Poor prognosis

Degenerative left shift

Morphological changes that occur in neutrophils when demand is very high and maturation time is shortened in the marrow

Toxic change

What is the earliest sign of toxic change?

Dohle bodies

How does cytoplasmic basophilia appear?

Streaky, diffuse blue appearance

What are the features of toxic change?

Dohle bodies, cytoplasmic basophilia, presence of vacuoles, giantism, toxic granulation

True or False: Toxic changes often accompany a degenerative “left shift” and are a negative prognostic indicator

True

Maturation and circulation times in the blood and tissues are similar to that for neutrophils

The greyhound is unique because the eosinophils contain vacuoles in the cytoplasm making it easy to confuse with monocytes

Eosinophils

What do eosinophils play a role in regulating and controlling?

Parasitic infections, allergic reactions, inflammation, coagulation and fibrinolysis

Increases numbers of circulating eosinophils

Parasitic infections and allergic reactions

Eosinophilia

Decreased numbers of circulating eosinophils

Stress or treatment with corticosteroids

Difficult to detect in most animals

Eosinopenia

Little is known about maturation and circulation or function since they are so rarely appreciated in circulation of most common domestic species

More commonly seen in horses and ruminants

Usually last for a total of 10-12 days from the time of production to entry into tissues from circulation

Basophils

Similar in structure and function to the mast cell

Stimulated by dust, molds viruses and other proteins

Release enzymatic granules composed of histamine and other enzymes

Initiate acute inflammatory reactions

Specific functions of basophils

Increases numbers of circulating basophils

Often seen with eosinophils in allergic reactions and parasitic infections

Often seen with mast tumor cells

Basophilia

Decreased numbers of circulating basophils

Of no clinical significance

Basopenia

Where are lymphocytes produced?

Bone marrow and lymphoid tissues (lymph nodes, spleen, thymus (fetus and neonate), GALT, tonsils, appendix)

Life span varies depending on intended function:

• lymphocytes last____

• Memory cells last for____

• days

• Years to a lifetime

_____produce antibodies in the humoral immune system

B lymphocytes

_____are part of the cell mediated immune response

T lymphocytes

Increased numbers of circulating lymphocytes

excitement, fear, anxiety, pain (stress), very young animals (age related), muscular exertion/exercise

Stimulation by viruses, blood parasites, and immunizations (acquired immunity)

Lymphocytosis

Maturation and circulation times are similar to those for other WBCs

Can last for months in the tissues as macrophages

Monocytes

Engulf fungi, protozoa, intracellular organisms, and bacteria

Remove debris and damaged cells following trauma

Process antigen for presentation to B and T lymphocytes

Phagocytosis

Chronic infection or inflammatory response

Necrosis

Conditions which initiate a granulomatous response

Fear, anxiety, excitement, pain (stress)

Monocytosis

Of no clinical significance

Monocytopenia