Page 129 - MNU microbiology theoritical 2025

General Microbiology & Immunology (PM 401) Second level Semester 4 2024/2025

3. Eosinophils

• Eosinophil cells are small granulocytes, which are produced in the bone marrow

and makes 2 to 3 per cent of whole WBCs.

• These cells are present in high concentrations in the digestive tract.

• Play a role in defense against parasitic infections.

• Eosinophilia is an indicator of parasitic infections.

• They seem to be involved in allergic reactions,

• The granules of eosinophils, which stain red with the acidic

dye eosin, contain antimicrobial substances and histaminase.

B. Agranulocytes

2- Monocytes

• Monocytes have a characteristic kidney-shaped nucleus.

• they migrate from the blood and develop into macrophages and dendritic cells in

tissue

Macrophages,

a differentiated form of monocytes, are phagocytic cells present in virtually all

tissues to at least some extent.

• They are particularly abundant in liver, spleen, lymph nodes, lungs, and the

peritoneal (abdominal) cavity.

• They are given various different names based on the tissue in which they are

found:

For example, Kupffer cells (in the liver) and alveolar macrophages (in the lung).

• Unlike PMNs they do not contain granules, but they have numerous lysosomes

which have contents similar to the PNM granules.

• Functions of macrophage: Phagocytize and digest engulfed materials

General Microbiology & Immunology (PM 401) theoretical handbook Page 118