Question

What does the memory cell remember?

Answer 1

If you get an infection, you can build up immunity to that specific virus. Memory cells are built in the body in response to these infections that help to fight in response to these viral or bacterial infections. They help in building up immunity against the infectious infection that our body encounters.

Complete answer:
Memory cells are long-lived immune cells that have the ability to recognition of foreign particles that they have encountered previously and consequently mount a faster and stronger immune system. These immune cells do not respond immediately to the first encounter of the antigens but facilitate rapid secondary response in response when the antigen is encountered on subsequent occasions.

They are major of two types:
Memory B cells- They are clones of parent B cells that have earlier served as an antigen-presenting cells and then activating the helper T cells. As they are clones, they bear the same B cell receptors as those of the parent B cell. Therefore, they detect the same antigen when re-exposed.

Memory T cells- They are called T lymphocytes and have a similar capability of recognition of foreign particles that they had encountered earlier. But they do not produce antibodies as memory B cells. On re-exposure, the pathogens cause them to clone themselves immediately and respond to infection more strongly.

As the name tells us, these cells remember the virus and bacteria they fought with. These cells live in the body of the person for a long duration even if all viruses have been destroyed after the first infection. These cells are in active mode to quickly recognize and attack any kind of returning virus or bacteria back in the body. They quickly make a lot of antibodies in the body to stop the infection in its tract. The first attack in the body takes up to 15 days to make antibodies while in the second attack it takes hardly 5 days. It makes 100 times more antibodies as compared to the first time.

Note: The first successful vaccine was made against the disease smallpox in the year 1796. It is caused by contagious and infectious viruses. It was Dr Edward Jenner who noticed women who milked cows caught up with cowpox. He discovered that maybe getting cowpox to prevent smallpox which later was used to find the vaccine for smallpox.