Lecture 4 Innate Immunity pt 2

What are PAMPS?

PAMPS (Pathogen-associated molecular patterns)

Specific molecular structures commonly found on the surface of pathogens, such as bacteria, viruses, fungi and parasites

What are DAMPs?

DAMPs (Damaged-associated molecules patterns)

Molecular motifs expressed on infected or damaged host cells

What are PRRs?

PRRs (Pattern recognition receptors)

Class of receptors that recognize common pathogen and damaged cell surface structures.

Where are PRRs found?

Found on and in innate immune cells

Macrophages and Dendritic cells

EXPRESSED on neutrophils, NK cells

What are the common PRR families?

TLRs (Toll like receptors)

CLRs (C-type lectin receptors)

FPRs (F-met-leu-phe receptors)

NLRs (NOD-like receptors)

RLRs (RIG-I-like receptors)

What are TLRs? (Toll-like receptors)

Expressed by macrophages, dendritic cells, and nonimmune cells like fibroblasts

Classified based on their cell localization

In humans, TLR family has 10 members (TLR 1-10)

Activated TLRs facilitate the initiation of adaptive immunity through pro-inflammatory cytokines

Protects the host from microbial infection

What TLRs are on the outer membrane?

T1, T2, T4, T5, T6

What TLRs are inside the cell?

T3, T7, T8, T9

What does TLR 10 do?

Contains an inhibitory function at the start of innate immune responses

What are CLRs? (C-Type Lectin receptors)

Membrane-bound receptors

Bind to carbohydrates in a calcium-dependent manner

involved in BACTERIAL and FUNGAL recognition

Modulate (adjust) the innate immune response

What are NLRs? (NOD-like receptors)

Intercellular PRRs

Detect intracellular PAMPs (Pathogen-associated molecular patterns), and danger signals

FORM inflammasomes

Inflammasomes help resolve infections

Contributes to cytokine-driven inflammation

What happens if NLRs are left behind?

Leads to chronic inflammation

What are RLRs? (RIG-I-Like Receptors)

Family of three cytoplasmic RNA helicases

Search for DOUBLE STRANDED RNA

Produce type 1 interferons in infected cells

Essential for host ANTIVIRAL responses

What are F-Met-Leu-Phe Receptors?

Mononuclear and PMN phagocytes

fMet is exclusively used by bacteria for protein synthesis initiation

Formylated peptides attract phagocytes to migrate to their position (chemotaxis)

What is important about f-Met?

Body will target f-Met due to only being used by bacteria for protein synthesis