> See also: > [[Biological Signaling]] # Immune Cell Receptors - Antigen Receptors A **ligand** is what a receptor structure binds to ## Compliment Receptors CR1 binds to C3b CR2 binds to C3d CR3 & CR4 bind to iC3b ## Antigen Receptors Antigen receptors allow immune cells to detect the presence of infectious microbes as well as diseased/damaged self cells ### Pattern Recognition Receptors (PRRs) The most common types of PRRs are: - **TLRs** - Toll-Like Receptors - **NLRs** - NOD-Like Receptors - *"Nucleotide-Binding Oligomerization Domain-Like Receptors"* - C-Type Lectin Receptors (CLRs) - RIG-1-Like Receptors (RLRs) Pattern recognition receptors are capable of recognizing: 1. **PAMPs** - Pathogen Associated Molecular Patterns 2. **DAMPs** - Damage Associated Molecular Patterns ### Antigen-Specific Lymphocyte Receptors - [[T-Cell Receptors (TCRs)]] - [[Antibodies|B-Cell Receptors (BCRs)]] ## Antibody Receptors [[Antibodies|Antibodies]] contain an Fc (fragment crystallizable) region on it's tail end which determines what type of receptors it can bind to and, as a result, what effects the antibody will cause. Fc Receptors (FcRs) ![[Fc Receptors.png|400]] Fc$\gamma$III | Name | Function | Expressed By | | --- | --- | --- | | Fc$\gamma$III | | NK Cells, Macrophages, Neutrophils, Eosinophil |