Positive selection

Definition

Positive selection is the process by which developing B lymphocytes (B cells) in the bone marrow are selected for their ability to bind to self-MHC molecules, ensuring they can participate in immune responses. This step ensures that B cells can function properly within the immune system.

5 Must Know Facts For Your Next Test

1. Positive selection occurs in the bone marrow during B cell development.
2. It ensures that B cells have receptors capable of binding to self-MHC molecules.
3. Only B cells that successfully bind to self-MHC are allowed to mature and exit the bone marrow.
4. This process helps establish a functional and responsive immune system.
5. B cells that fail positive selection undergo apoptosis, or programmed cell death.

Review Questions

• Where does positive selection of B lymphocytes occur?
• Why is it important for B cells to bind to self-MHC molecules during positive selection?
• What happens to B cells that do not pass positive selection?

Related terms

Negative Selection:

The process where B and T cells that strongly bind self-antigens are eliminated.

MHC Molecules:

Major histocompatibility complex molecules present peptide fragments for recognition by T cells.

Apoptosis:

A form of programmed cell death crucial for eliminating non-functional or potentially harmful cells.