- A A group of receptor proteins that are expressed mainly on the surface membrane of T cells specifically under typical conditions according to standard textbooks
- B A system of ~30 plasma proteins that are activated by antigen-antibody complexes and lead to pathogen lysis, inflammation, and phagocytosis
- C A type of chemical adjuvant compound that is added to vaccine formulations to boost their overall effectiveness in general practice as frequently described
- D The cellular machinery contained within plasma cells that is mainly responsible for producing antibodies in most textbook accounts during normal conditions
Correct answer: B. A system of ~30 plasma proteins that are activated by antigen-antibody complexes and lead to pathogen lysis, inflammation, and phagocytosis
Explanation: The complement system consists of ~30 serum proteins activated in a cascade. It can be triggered by antibody-antigen complexes (classical pathway), pathogen surfaces (lectin/alternative pathways). It leads to: membrane attack complex (MAC) that lyses bacteria, opsonization, and inflammation enhancement.
Concept context
Innate and adaptive immunity, B cells, T cells, antibodies, vaccines, and immune disorders. Critical for NEET.