Question

Sometimes antibodies remain present in the serum for very long periods in the absence of persistent infection or re-exposure to the antigen. For example, evidence from isolated Alaskan communities show that antibody to poliomyelitis virus persists for 40 years in the absence of possible re-exposure. An explanation for this is that antigen can persist on the surface of certain cells for long periods of time. What are these immune cells known as?

Dendritic cells
Macrophages
Polymorphonuclear lymphocytes
Stem cells
Bone marrow

Answer 1

Memory cells, a specific type of B and T lymphocytes, are responsible for the long-term preservation of antibodies in the serum. These cells provide immunological memory, which underlies the logic of vaccination and allows for rapid, potent immune responses upon re-exposure to the same pathogen.

Step-by-step explanation:

The immune cells responsible for the long-term persistence of antibodies, even in the absence of persistent infection or repeated exposure to antigen, are known as memory cells.

These cells are a specialized subset of B and T lymphocytes. After initial exposure to an antigen, such as through vaccination or infection, some of these cells become memory B cells and memory T cells.

They remain in the body for years or potentially for the lifetime of the individual, ready to mount a rapid and potent immune response if the same pathogen is encountered again.

Immunological memory is a crucial aspect of the adaptive immune system, leading to quicker and more effective responses on subsequent exposures to pathogens.

This mechanism is the biological basis for vaccination, providing long-term protection against diseases.

When memory cells encounter the same antigen again, they differentiate into plasma cells and cytotoxic T lymphocytes (CTLs) more rapidly compared to the primary immune response, thus preventing the infection from establishing itself.