Answer: Innate uses germline-encoded PRRs (TLRs, NLRs) that recognize conserved PAMPs on pathogens (broad, rapid, no memory); adaptive uses V(D)J recombination-generated diverse TCR/BCR for specific antigens (slow, memory-forming).
- A Both are sometimes thought to use the same receptors, with germline-encoded TLRs and the somatically diverse, V(D)J-recombined TCR/BCR repertoire being functionally interchangeable in practice in general practice as frequently described
- B Innate uses germline-encoded PRRs (TLRs, NLRs) that recognize conserved PAMPs on pathogens (broad, rapid, no memory); adaptive uses V(D)J recombination-generated diverse TCR/BCR for specific antigens (slow, memory-forming)
- C Adaptive is sometimes thought to be faster than innate, despite adaptive immune responses actually taking several days to largely develop, in contrast to rapid innate responses observed in most textbook accounts during normal conditions
- D Innate is sometimes thought to have memory while adaptive does not, when in fact long-lived immunological memory is widely understood to be a defining feature of the adaptive system instead as generally observed in typical laboratory settings
Correct answer: B. Innate uses germline-encoded PRRs (TLRs, NLRs) that recognize conserved PAMPs on pathogens (broad, rapid, no memory); adaptive uses V(D)J recombination-generated diverse TCR/BCR for specific antigens (slow, memory-forming)
Explanation: Innate PRRs (Toll-like receptors, NOD receptors, STING): germline-encoded, recognize conserved pathogen-associated molecular patterns (PAMPs) like LPS, flagellin, dsRNA. Adaptive receptors (TCR, BCR): somatically generated by V(D)J recombination creating ~10<sup>18</sup> possible specificities, each lymphocyte having unique receptor.
An antibody is Y-shaped, with two identical antigen-binding sites at the tips of the variable regions - each shaped to recognise one specific antigen - while the constant (Fc) region at the base is recognised by immune cells to trigger further responses.
Concept context
Innate and adaptive immunity, B cells, T cells, antibodies, vaccines, and immune disorders. Critical for NEET.