Toll-like receptors Scavenger Receptors Part of the innate immune response. Let´s talk first. Innate Immunity Pathogen recognized by receptors encoded in the germline: p attern r ecognition r eceptors
Part of the innate immune response
Let´s talk first...
Pathogen recognized by receptors encoded in the germline: pattern recognition receptors
Receptors have broad specificity, i.e., recognize many related molecular structures called PAMPs (pathogen-associated molecular patterns)
No memory of prior exposure
Pathogen recognized by receptors generated randomly: B-cell (BCR) and T-cell (TCR) receptors for antigen
Receptors have very narrow specificity; i.e., recognize a particular epitope after processing
Slow (3 -5 days) response (because of the need for clones of responding cells to develop)
Memory of prior exposureInnate vs. Adaptive Immunity
Anatomical barriers: Skin, Intestinal movement, Oscillation of broncho-pulmonary cilia
N. B. All components of the non-specific immune system are modulated by products of the specific immune system, such as interleukins, interferon-g, antibody, etc.
How does the host organism detect the presence of infectious agents and dispose of them without destroying self tissues? How non-specific is innate immunity really ?
Innate Immune Recognition agents and dispose of them without destroying self tissues? via Patterns
Functions of membrane bound lectins agents and dispose of them without destroying self tissues?
produced by dendritic cells and
- MMR, DEC-205 (CD205), and Dectin-2:
Antigen Uptake, DC trafficking.
- Dectin-1 and DC-SIGN (CD209):
T-cell interaction, DC trafficking.
! C-type lectin receptors also recognize
glycosylated virus envelope proteins but
some viruses appear to utilize these
as attachment (& entry?) receptors.
Peiser I agents and dispose of them without destroying self tissues? nfect Immun. 2002;
70 (10): 5346–5354
FIG. 3. EM of N. meningitidis uptake. WT and SR-A-/- BMM were incubated for various times with 150 live MC58 bacteria per cell at 37°C.
At various intervals, the cells were washed to remove extracellular bacteria before being processed and analyzed by EM.
The fields chosen are representative of the whole M population
Toll-like receptors agents and dispose of them without destroying self tissues?
TLR signaling pathways agents and dispose of them without destroying self tissues?
Nature Immunology 2001 2:675
Phagocytosis and immune
recognition of M. tuberculosis.
Tailleux et al., J Exp Med. 2003;197(1):121-7. : „DC-SIGN is the major Mycobacterium tuberculosis receptor on human dendritic cells“.
Complement receptor (CR)3 and mannose receptor (MR), which are the main M. tuberculosis receptors on macrophages, appeared
to play a minor role, if any, in mycobacterial binding to DCs.
The mycobacteria-specific lipoglycan lipoarabinomannan (LAM) was identified as a key ligand of DC-SIGN.
Recommended reading: Immunity
Zhang and Ghosh: Toll-like receptor-mediated NF-kB activation:
a phylogenetically conserved paradigm in innate immunity
J Clin Invest 107, 13-19, 2001
C-type lectins in DC trafficking