The complement system can lead to the removal or destruction of invading microbes and the inflammatory response. Which immune response of the complement system is not effective against gram-positive (+) pathogenic bacteria?

• A. Opsonization of invading microbe.
• B. Inflammatory response.
• C. Cell lysis of invading microbe.

Answer: (C)

Verified step by step guidance

1. Understand the complement system: The complement system is a part of the immune system that enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells, promotes inflammation, and attacks the pathogen's cell membrane.
2. Identify the mechanisms of the complement system: The complement system can lead to opsonization, inflammation, and cell lysis. Opsonization involves marking pathogens for phagocytosis, inflammation recruits immune cells to the site of infection, and cell lysis involves the destruction of the pathogen's cell membrane.
3. Recognize the structure of gram-positive bacteria: Gram-positive bacteria have a thick peptidoglycan layer in their cell wall, which provides structural integrity and protection against certain immune responses.
4. Analyze why cell lysis is ineffective against gram-positive bacteria: The thick peptidoglycan layer in gram-positive bacteria makes it difficult for the complement system to penetrate and lyse the cell membrane, rendering cell lysis ineffective.
5. Conclude the effectiveness of other responses: While cell lysis is ineffective, opsonization and the inflammatory response can still be effective against gram-positive bacteria by facilitating phagocytosis and recruiting immune cells to the site of infection.