Internalization

Definition

Internalization is the process where a cell engulfs and incorporates foreign particles, such as antigens or pathogens, into its cytoplasm. This is a critical step in the immune response for antigen processing and presentation.

5 Must Know Facts For Your Next Test

1. Internalization by B lymphocytes typically occurs through receptor-mediated endocytosis.
2. Once internalized, antigens are processed into smaller fragments within endosomes and lysosomes.
3. The antigen fragments are then presented on the cell surface in association with MHC class II molecules.
4. This process is essential for the activation of helper T cells and the subsequent adaptive immune response.
5. Internalization helps B cells act as antigen-presenting cells (APCs), which is crucial for their role in humoral immunity.

Review Questions

• What cellular process allows B lymphocytes to engulf and incorporate antigens?
• Why is internalization important for B cells in their role as antigen-presenting cells?
• How do internalized antigens contribute to the activation of helper T cells?

Related terms

Endocytosis:

The process by which a cell takes in material by enveloping it with its membrane.

MHC Class II molecules: Proteins on antigen-presenting cells that display processed antigens to helper T cells.

Antigen-Presenting Cells (APCs):

Cells that process and present antigens to T-cells, initiating an immune response.