The first line of defense in the human body is WBCs which are also known as leukocytes are the cells of the immune system. It circulates throughout the blood and lymphatic system. Leukocyte plays important role in the immune system by identifying, destroying, and removing pathogens and damaged cells. These cells can leave blood cells and migrate through body fluids. Leukocytes originate in the bone marrow and circulate in lymph nodes. Leukocytes can be characterized by the presence and absence of granules (Sacs containing digestive enzymes or other chemical substances) in the cytoplasm. If there is the presence of granules are granulocytes and if there absence of granules they are called agranulocytes. Granulocytes include Eosinophile, Neutrophiles, and basophils. Agranulocytes are monocytes and lymphocytes.
Granulocytes
Granulocytes are the types of white blood cells that are present in the cytoplasm in the form of granules. They are also known as polymorphonuclear leukocytes.
Three different types of granulocytes can be differentiated by the stain.
Eosinophils
- Identify by the acidic stain.
- The most common stain ( H&E-stain, Congo red).
- Double lobed nucleus and appear U-shaped blood smear.
- Active when allergic infection occurs.
- Usually found in the connective tissue of the stomach and intestine.
- Eosinophils are phagocytic they target antigen-antibody complexes.
Neutrophils
- Most abundant in nature.
- Identify Alkaline buffer solution ( basic).
- It has a single nucleus with multiple lobes.
- They chemically draw bacteria and migrate toward the infection site.
- They act as lysosomes digest cellular macromolecules.
- Neutrophils are phagocytic, they engulf bacteria.
Basophils
- Can identify by the basic dye.
- Least abundant in nature.
- Multilobed nucleus is seen during stain.
- They have Histamine & Heparin act immunity boosters.
- Histamine acts during allergic response and heparin act in blood clot formation.
Also Read: Gram Staining
Agranulocytes
Agranulocytes are white blood cells that have no granules. They present one nucleus that’s why they are known as mononuclear leukocytes. They have larger nuclei due absence of unnoticeable granules.
Three types of Agranulocytes are:
Monocytes
- They present large numbers.
- They have large nucleus structures and kidney-shaped structures ( Sometimes called amoeboid structures).
- Monocyte develops macrophages and dendritic cells.
- It activates an inflammatory reaction.
- It can activate adaptive immune responses.
- Monocytes release cytokines and chemokines.
Types of monocytes
-
Macrophage
- Present in almost all tissue.
- They actively perform phagocytic functions.
-
Dendritic Cells
- Act as the neurotransmitter connects with external antigens.
- Their primary function is to provide the presence of antigens to lymphocytes.
- They are unicellular, and their projection same as dendrites.
Lymphocytes
- Most commonly found in the cytoplasm after neutrophils.
- Spherical in shape.
- They have a very large nucleus with low cytoplasm.
- The main types of lymphocytes- are T-cell, B-cell, and Natural killer cells.
- They are natural killer cells.
Difference between Granulocyte and Agranulocyte
Granulocytes |
Agranulocytes |
|
Definition |
|
| Contain granules in the cytoplasm. | Does not contain granules in the cytoplasm. |
|
Cells Produces |
|
| Basophils, Neutrophils, Eosinophils. | Monocytes and Lymphocytes. |
|
Immunity |
|
| Granulocytes are involved in innate immunity. | Agranulocytes involve in adaptive immunity. |
|
Origin |
|
| Originates from Bone marrow. | Originates from lymph nodes. |
|
Nucleus |
|
| Granulocytes are known as polymorphonuclear leukocytes. | Agranulocytes are known as mononuclear leukocytes. |
|
Antibodies Response |
|
| Produces Histamine. | Doesn’t Produces histamine |
|
Most-Effective |
|
| Can Kill parasites. | Can’t kill Parasites. |
|
Cells Produced |
|
| Produces from myeloid stem cell | Produces from a lymphoid stem cell. |
|
Type of Immunity |
|
| Innate general Immunity. | Specific and Humoral Immunity. |
|
Concentration |
|
| 65% of total leukocytes. | 35% of total leukocytes. |
|
Enzymes Present |
|
| Contain enzyme, Phagocytic particles & Inflammatory responses. | Contain enzyme in lysozyme. |
Summary
Granulocytes are the WBCs that help fight against infection they have their own specific enzymes. It increases the response to infection. Agranulocytes need recognition by leucocytes and they can kill pathogens as well as cells. They can be distinguished by the stain and presence of granules it can be observed under a light microscope. Difference between each of every cell according to their specific function for phagocytic, allergic response, etc.
FAQs on Granulocyte and Agranulocyte
Question 1: Which type of stain is used to detect Eosinophils?
Answer:
Acidic stain, H&E-stain, Congo red stain.
Question 2: Why agranulocytes are showing large nuclei?
Answer:
Agranulocytes are showing large nucleus due to unnoticable granules are present in cytoplasm.
Question 3: What does immature granulocyte indicate?
Answer:
The early stage of infection in blood represents by immature granulocyte.
Question 4: What is the function of lymphocytes?
Answer:
Lymphocytes are part of acquired immunity. They produce antibody and kills the infected cell of the body.