PRRs vs. Antigen Receptor

Immune Recognition

PRRs

Mammals detect microbe‑specific, conserved structures—PAMPs such as nucleic acids and microbial cell‑wall components—using LRR‑based PRRs on the surface, in endosomes, and in the cytosol, which trigger strong activating and pro‑inflammatory responses

TLRs and NOD1 drive

Proinflammatory cytokines through NF-kB

Viral sensors drive

Interferon production

Inflammasome forming NLRs give

sensitive, near binary, very proinflammatory signal

NLRs recognize

PAMPs and DAMPs

Innate Receptors

PRRs, LRR motifs

Adaptive

Ig superfamily, two chains

Antibodies

two identical heavy and two identical light chains; variable domains bind antigen, constant domains give structure. the variable loops that recognize ligand

Ig domain

antiparallel beta sheets, disulfide stabilized, very stable

BCR binds directly

TCR sees short peptides on MHC. Both use co-receptors for signaling

Hallmarks of Adaptive immunity

Specificity and Memory

Antigen Binding are mediated by

Variable Domains

Antibodies are

homodimers of heterodimers

BCR Binds

directly

Cells that drive adaptive immunity

Lymphocytes (B and T cells)

Lymphocytes recognize antigen with what?

Diversified antigen receptors

Adaptive immunity is driven by

Rare B and T cells that are very specific for small pieces of antigens (epitopes)

rare antigen specific lymphocytes that are activated

clonally expand

B cells generate

antibodies

T cells generate

Cytokines and mediate cytotoxicity

Ig superfamily

proteins are built from repeating Ig domains

Antigen receptor’s CDR mediate

antigen recognition

B Cell receptors ___ recognize pathogens

Directly

T cell receptors recognize

pieces of pathogens present on MHC Molecules

B and T cells use ___ to transduce signals

co-receptors

B cell antigen receptors are secreted as ___ that share the antigen binding properties of BCR

Soluble antibodies

Antibodies come in ___ with specialized effector functions

B and T cells can both recognize ___ but not usually the same ____