Which of the following would be an effective defense against bacteria but not against bacteria but not against viral particles?
A. Secretion of interferon by an infected cell
B. Neutralization by antibodies
C. Agglutination or precipitation by antibodies
D. A secondary immune response
E. membrane attack complex formed by complement
---I have ruled out B and D but am unsure from there...
Please help on my question!
E. membrane attack complex formed by complement
To determine which of the remaining options would be an effective defense against bacteria but not against viral particles, let's analyze each choice:
A. Secretion of interferon by an infected cell: Interferons are proteins produced by infected cells as part of the immune response. They have antiviral effects and can help inhibit viral replication and spread. However, interferons do not have a direct antibacterial effect. Therefore, this option would not be an effective defense against bacteria.
C. Agglutination or precipitation by antibodies: Antibodies are produced by the immune system in response to infection. They can recognize and bind to specific antigens on both bacteria and viral particles. Agglutination refers to the clumping together of particles due to the binding of antibodies, while precipitation refers to the formation of a visible insoluble complex. Both agglutination and precipitation can occur when antibodies bind to either bacteria or viral particles. Therefore, this option does not differentiate between bacteria and viral particles.
E. Membrane attack complex formed by complement: The complement system is a part of the immune system that helps eliminate pathogens, including bacteria and viral particles. The membrane attack complex (MAC) is a group of complement proteins that can form pores in the membranes of target cells (both bacterial and host cells), leading to cell lysis. Therefore, the membrane attack complex is effective against both bacteria and viral particles.
Based on this analysis, the correct answer would be A. Secretion of interferon by an infected cell. This defense mechanism is effective against viral particles but not against bacteria.