Question

The most active phagocytic white blood cells are
A) Eosinophils and lymphocytes
B) Neutrophils and monocytes
C) Neutrophils and eosinophils
D) Lymphocytes and macrophages

Answer 1

Hint: The white blood cells are the cells of the immune system which helps in protection of the body against foreign agents. Phagocytic cells help in phagocytosis by engulfing pathogens.

Complete Answer:
- The phagocytosis is a mechanism by which some living cells known as phagocytes engulf other cells that are pathogen or cell debris by using its plasma membrane.
- The WBC called leukocytes are divided into granulocytes and agranulocytes .
- The granulocytes - Neutrophils, eosinophils and basophils.
1) Neutrophil- Fight against Bacterial and fungal infection. They are a type of phagocyte .
2) Eosinophil- Fight against parasitic and allergic infections.
3) Basophil- Allergic and antigen response.

- Agranulocytes- Lymphocyte and monocyte
1) Lymphocyte -Antibody production and helps in cellular immune response.
2) Monocyte- Phagocytosis of pathogens. Presentation of antigen to T cells.

- Monocytes are the largest type of leukocyte which can be differentiated into macrophages and myeloid lineage dendritic cells.
- Three main functions:
1) Antigen presentation.
2) Phagocytosis.
3) Cytokine production.

- Monocytes perform phagocytosis by using proteins such as antibodies.
- Neutrophils are phagocytes which ingest microorganisms or particles by the process called as antibody opsonization.
- Thus, phagocytosis by neutrophils and monocytes is a key process in innate immune response.

The most active phagocytes are Neutrophils and Monocytes. So the correct answer is Neutrophils and Monocytes.

Note: The PMNs (POLYMORPHONUCLEAR LEUKOCYTES ) Includes neutrophils, eosinophils, basophils which are responsible for the immunity.