1. THE BASICS OF LEUKOCYTES
Ms. Nelson, LVT

2. THERE ARE 5 WHITE BLOOD CELLS
Segmented Neutrophil
Lymphocyte
Monocyte
Eosinophil
Basophil

3. What are they for?
Each type of WBC plays an important role in the body’s defense system
The total concentration of each type is extremely valuable for the diagnosis of various diseases.
Some of the functions of the WBC’s include
Phagocytosis
The release of substances that modulate the immune system
The production of antibodies

4. LET’S BREAK THEM DOWN! Granulocytes Agranulocytes Segmented Neutrophil
Eosinophil
Basophil
Agranulocytes
Lymphocyte
Monocyte
Neutrophil blood levels increase naturally in response to infections, injuries, and other types of stress (they help with tissue damage)
Eosinophil are involved in inflammatory response
Basophil are involved in allergic response (they contain heparin which prevents blood from clotting too quickly)
Lymphocytes are part of our immune defense and act to recognize antigens, produce antibodies, and destroy cells that could cause damage
Monocytes are a type of white blood cell that fights off bacteria, viruses and fungi. Monocytes are the biggest type of white blood cell in the immune system.

5. THE AGRANULOCYTES (NO GRANULES IN CYTOPLASM)
The Monocyte
The Lymphocyte
If there appears to be granules in a Monocyte’s cytoplasm, it is probably debris from it’s last meal!
Look for vacuoles (Stomachs) to tell if it is a Monocyte.
Lymphocytes are part of our immune defense and act to recognize antigens, produce antibodies, and destroy cells that could cause damage
Monocytes are a type of white blood cell that fights off bacteria, viruses and fungi. Monocytes are the biggest type of white blood cell in the immune system

6. THE GRANULOCYTES (HAVE GRANULES IN CYTOPLASM)
Segmented Neutrophils (there are 3 types)
Basophils
Eosinophils
On Basophils, the granules will stain BLUE
On Eosinophils, the granules will stain RED
Segmented Neutrophils granules are clear and not readily visible when stained.
Neutrophil blood levels increase naturally in response to infections, injuries, and other types of stress (they help with tissue damage)
Eosinophil are involved in inflammatory response
Basophil are involved in allergic response (they contain heparin which prevents blood from clotting too quickly)

7. BAND CELL (THE “BABY” NEUTROPHIL)
Sometimes called Stab cell. Immature neutrophil and indicates that there is a high demand for Neutrophils during an inflammatory response.
These are normally still in the bone marrow

8. How to identify
Nucleus will be horseshoe shaped, with large round ends.
Some slight indentations may be present in the nucleus,
If ever in doubt if there is segmented lobes, you should categorize the cell as a segmented neutrophil.

9. Band Neutrophils

10. SEGMENTED NEUTROPHIL (THE ADULT)

11. Neutrophils
Neutrophils are the most common WBC in the peripheral blood of most mammals
Their main function is to phagocytize
Primary WBC found in pus. First responder to acute inflammation either from trauma or bacterial infection and can reach the sight of inflammation within minutes
Increased numbers in a CBC indicate there is a infection or inflammation
Only live for ~5 days
When found in avians, reptiles, some fish, and some small mammals (rabbits, guinea pigs), the cell that is functionally equivalent to the neutrophil is called a heterophil
Heterophils will have distinct eosinophilic granules in their cytoplasm
They are the first cells to migrate to the site of the infection to begin killing the invading microbes
These are the second line of defense, after skin and/or mucous membrane. There granules contain digestive enzymes (lysosomes) that are capable of destroying bacteria and viruses (they engulf them)
The leave the blood and go to the tissues where they will die of old age

12. How to identify
The nucleus of the neutrophil is irregular and elongated
True filaments between these lobes is rare.
The presence of 3-5 lobes is characteristic.

13. Neutrophil

14. HYPER-SEGMENTED NEUTROPHIL (THE SENIOR CITIZEN)

15. Has been in circulation
How To Identify
5+ lobes.
Has been in circulation
Usually an indicator of iron deficiency anemia.
If a hypersegmented neutrophil is seen in the peripheral blood, this indicates that the neutrophil has stayed in circulation longer than normal.
These can be seen due to a pathological condition that prevents neutrophils from leaving or it could be from using an old sample. Blood will continue to age even after it has been pulled from the patient.

16. Hyper segmented Neutrophils

17. LYMPHOCYTE (THE GUARD DOG) LARGE NUCLEUS
Second most common in blood. Are responsible for defending against tumors, bacteria. viruses, and other foreign invaders.
Three types: T-cells (LONG LIVED = YEARS), B-cells (SHORT LIVED = MONTHS at longest) and Natural killer cells. They differentiate which of these three is needed for the particular invader and some develop a “memory” to the invader so that it can be more easily fought if it shows up again.

18. Lymphocyte Second most common in blood.
Responsible for defending against tumors, bacteria, viruses, and other foreign invaders.
Three types:
T-cells
B-cells
NK cells

19. T-Cell Lymphocyte T-cells (LONG LIVED = YEARS)
Play a major role in cell mediated immunity
They are called T cells because they mature in the thymus from thymocytes
play a central role in cell-mediated immunity
T-cells are processed in the thymus before going to the peripheral lymphoid tissue. Once they leave the thymus, they are called T-cells or T-lymphocytes.
Thymocytes multiply rapidly, leave the thymus, and travel to specific T-dependent zones in lymph nodes and spleen. (most of lymphocytes in peripheral blood are T-cells)
Cell-mediated immunity means they use other cells or cytokines to fight off invaders.
T-cells ae responsible for cell-mediated immunity and activating B-cells

20. B-Cell Lymphocyte B-cells (SHORT LIVED = MONTHS at longest)
B cells, unlike the other two classes of lymphocytes, express B cell receptors (BCRs) on their cell membrane. BCRs allow the B cell to bind a specific antigen, against which it will initiate an antibody response.
Inactive B-cells travel through lymph nodes, the spleen, and rarely circulate in peripheral blood.
B-cells are responsible for antibody production. Each B-cell is programmed to produce only one specific antibody type against one specific antigen (foreign protein).
On its surface, it has thousands of receptors shaped to fit only one antigen shape (every antigen has its own unique shape on its surface).
When the B-cell and antigen are joined, an antigen-antibody complex is formed (example: there are specific B-cells preprogrammed for Canine Distemper, other B-cells won’t be affected). The B-cells preprogrammed to recognize the virus will respond by making antibodies against the virus.
B-cells are preprogrammed to produce antibodies against antigens to which they have never been exposed. When a B-cell recognize an antigen, they transform into plasma cells that release antibodies.

21. NK Cell Lymphocyte
NK cells. They differentiate which of these three is needed for the particular invader and some develop a “memory” to the invader so that it can be more easily fought if it shows up again.
These are not activated by a specific antigen. They have the ability to kill some types of tumor cells and cells infected with various viruses.
They release a cytotoxin that lysis the invader.

22. More about the lymphocyte
Their main function is to produce antibodies for the body to fight infection.
They will increase in numbers if a viral infection is present and cue the other WBC’s to begin killing the invader

23. Lymphocyte

24. MONOCYTE (THE SCAVENGER) HAS VACUOLES

25. Monocyte Third most common in blood.
When needed, migrate through bloodstream in about 24 hours to site of infection.
Phagocytize primarily in tissue, but can be mildly phagocytic in bloodstream.
If they leave the bloodstream, they are called MACROPHAGES.
Will only live a few days in circulation before travelling to the tissues and becoming a macrophage.
Immediately die after phagocytizing.

26. How To Identify
These will be the largest of the WBCs in the peripheral blood
Contain a variably shaped nuclei
Nucleus is occasionally the shape of a kidney bean, but is often elongated or lobulated.
Nuclear chromatin is more diffuse in monocytes than in neutrophils
Cytoplasm is blue, and contains vacuoles
Diffuse: wide

28. Monocyte

29. EOSINOPHIL (THE ALLERGY SLAYER) GRANULES STAIN RED

30. Eosinophil 4th most common in blood.
Primary function is defense against parasites and allergies.
Cells are attracted to histamines and other substances that are released during allergic reaction.
Histamines and other substances are toxic not only to the invader, but also the host! What can shut this process off?
Life-span = 8-12 hours in circulation or 8-12 days in the tissue if not required to respond to invader.

31. How To Identify
Contains a nucleus that is similar to a neutrophil, but the chromatin is usually not coarsely clumped.
Usually stain dark red and round.
Will be in larger numbers in patients that are having an allergic reaction, parasite infestation, or parasitic infection

32. Eosinophil

33. BASOPHIL (THE UNKNOWN STRANGER)

34. Basophil Least common in the blood.
They too can migrate to the tissue from the bloodstream when needed.
Job is not well defined, however granules have been identified as containing histamine and heparin that is used to attract eosinophils to help with response to allergies or other invaders.
Live just a few days.

35. How To Identify
Cytoplasm granules will stain blue

36. Basophil

37. LETS COMPARE!

38. SIZE COMPARISON

39. Fin!