APC
📘 Short Note on Antigen-Presenting Cells (APCs)
Antigen-Presenting Cells (APCs) are specialized immune cells that process and present antigens to T lymphocytes, initiating an adaptive immune response.
🔍 Key Features of APCs:
Feature | Description |
|---|---|
Function | Capture antigens, process them, and present antigen fragments on MHC (Major Histocompatibility Complex) molecules to T cells |
Types of MHC | MHC I – presents to CD8+ cytotoxic T cellsMHC II – presents to CD4+ helper T cells |
🧬 Major Types of APCs:
APC Type | Role |
|---|---|
Dendritic cells | Most effective and professional APCs; activate naive T cells |
Macrophages | Engulf pathogens and present antigens to helper T cells |
B cells | Present antigens to helper T cells to get activated and produce antibodies |
🧠 Summary:
APCs are crucial for activating T cells and linking innate immunity to adaptive immunity.
They help the immune system recognize and respond to pathogens by showing them to T cells in a "visible" form.