Immunity as a Consequence of Retaining Memory Cells
- Immunity is the ability of the body to defend itself against specific pathogens, preventing reinfection by the same pathogen.
- The body’s ability to quickly recognize and eliminate a previously encountered pathogen is largely due to the presence of memory cells, which are long-lived lymphocytes that “remember” past infections
Think of memory cells as a "most-wanted" list that helps your immune system quickly recognize and neutralize familiar threats.
What is Immunity?
Definition
Immunity
The ability of the body to defend against infections by recognizing and eliminating pathogens.
- Immunity is your body’s ability to eliminate an infectious disease before it causes harm.
- It relies on the adaptive immune system, which learns from past encounters with pathogens.
- Once you’ve had chickenpox, your immune system creates memory B-cells and T-cells specific to the varicella-zoster virus.
- If you're ever exposed to the virus again, these memory cells will quickly activate and generate a rapid immune response, preventing you from getting sick again or reducing the severity of the disease.
The Role of Memory Cells
- Memory cells are long-lived lymphocytes (B-cells and T-cells) that remain in the body after an initial infection.
- These cells "remember" the pathogen by maintaining a record of its specific antigens.
- When the body encounters the same pathogen in the future, memory cells quickly recognize it and trigger a swift immune response.
- Don’t confuse memory cells with antibodies.
- Antibodies are short-lived, but memory cells can persist for years, ready to produce new antibodies when needed.
How Memory Cells Are Formed
- When a pathogen invades, B-lymphocytes (a type of white blood cell) are activated to produce antibodies.
- Most of these B-lymphocytes become plasma cells, which secrete antibodies to fight the infection.
- Once the infection is cleared, most plasma cells die, but a small number of B-lymphocytes differentiate into memory B-cells.
