Chlamydia can prevent the formation of phagolysosomes and therefore can
a. avoid being phagocytized.
b. avoid destruction by complement.
c. prevent adherence.
d. avoid being digested.
e. none of the above

Verified step by step guidance

1. Understand the role of phagolysosomes in the immune response: Phagolysosomes are formed when a phagosome, containing an engulfed pathogen, fuses with a lysosome, which contains digestive enzymes.
2. Recognize that Chlamydia can prevent the formation of phagolysosomes, which means it can avoid the digestive enzymes that would normally break it down.
3. Consider the options given: a. avoid being phagocytized, b. avoid destruction by complement, c. prevent adherence, d. avoid being digested, e. none of the above.
4. Evaluate each option: a. Phagocytosis is the process of engulfing pathogens, which is not prevented by Chlamydia's action. b. Complement destruction is a different immune mechanism not directly related to phagolysosome formation. c. Adherence is the initial step of pathogen attachment, not related to phagolysosome formation. d. Avoiding digestion is directly related to preventing phagolysosome formation.
5. Conclude that the correct answer is the option that directly relates to avoiding digestion, as preventing phagolysosome formation allows Chlamydia to avoid being digested.

Key Concepts

Phagocytosis

Phagocytosis is a cellular process where immune cells, such as macrophages and neutrophils, engulf and digest pathogens or debris. This process involves the formation of a phagosome, which then fuses with lysosomes to form a phagolysosome, where the engulfed material is broken down. Understanding this mechanism is crucial for comprehending how pathogens like Chlamydia evade immune responses.

Phagolysosome Formation

The phagolysosome is a specialized compartment formed when a phagosome fuses with a lysosome. This fusion is essential for the destruction of engulfed pathogens, as it creates an acidic environment and activates digestive enzymes. Chlamydia's ability to prevent phagolysosome formation allows it to survive within immune cells, highlighting its pathogenic strategies.

Immune Evasion Mechanisms

Pathogens have evolved various immune evasion mechanisms to survive host defenses. These include preventing phagocytosis, inhibiting phagolysosome formation, and resisting destruction by immune factors. Chlamydia's ability to avoid being digested by preventing phagolysosome formation exemplifies such strategies, making it a successful intracellular pathogen.