Immunity is a complex process of cells and organs working together to guard your body against germs and the toxic chemicals they produce. Your immune system is on-call 24/7, and it never stops fighting to protect you. It’s a little like your home security system — always watching for intruders and ready to sound the alarm when needed.
The innate immune system is your first line of defense, and it responds to invading germs as soon as they enter your body. The white blood cells that make up this system do not need prior training to recognize certain invaders and they do not offer protection against specific germs or the infections they cause in the future.
Activated B cells bind to antigens and produce antibodies, which neutralize or mark the invaders for destruction by other immune system cells. Activated T cells then help the B cells kill pathogens and destroy any remaining bacterial or viral debris in the body. Lymphocytes release inflammatory molecules called chemokines, which attract neutrophils and other immune system cells to the site of infection.
After your immune system clears away an invading pathogen and you recover, memory cells remain at the site of the infection to detect it again. If the same invader tries to come back, the memory cells will respond much faster and more efficiently.
Infections that occur at mucosal sites (respiratory, gastrointestinal, and genital tracts) generally produce immunity that lasts for life. Infections that happen at the skin, however, tend to only produce temporary immunity. This is why it’s important to get vaccinated, as the vaccines help provide long-lasting immunity.