Page 112 - MNU microbiology theoritical 2025
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General Microbiology & Immunology (PM 401) Second level Semester 4 2024/2025
3. Iron binding proteins:
Lactoferrin is an iron binding protein, these proteins competes with bacteria for iron
which is an essential nutrient for bacteria , thereby inhibiting bacterial growth.
4. The complement system
- It is a group of serum proteins (approximately 30 serum proteins).
- Synthesized in the liver and by cells involved in inflammatory response.
The complement system has three major activities:
o Initiation of the inflammation.
o Identifying materials for removal by phagocytic cells (opsonization).
o Lysing a susceptible bacterial cell.
Complement Activation
- Involves a “cascade” of successive components.
- Components are cleaved into activated fragments (subunits, a and b)
- Fragments induce intense inflammatory responses to eliminate infectious agents.
Pathways of the complement activation
1- Classical pathway which is activated by Ab bound to Ag >96 hour.
2- The lectin pathway is activated by carbohydrates after 4-96 hour.
3- Alternative pathways activated in the presence of various microbial pathogens
0- 4 hr.
General Microbiology & Immunology (PM 401) theoretical handbook Page 101
