What is clonal expansion of T cells?

Clonal selection is the theory that specific antigen receptors exist on lymphocytes before they are presented with an antigen due to random mutations during initial maturation and proliferation. After antigen presentation, selected lymphocytes undergo clonal expansion because they have the needed antigen receptor.

What does clonal expansion mean?

Abstract. Clonal expansion of lymphocytes is a hallmark of vertebrate adaptive immunity. A small number of precursor cells that recognize a specific antigen proliferate into expanded clones, differentiate and acquire various effector and memory phenotypes, which promote effective immune responses.

What happens clonal expansion?

Clonal expansion is the process by which daughter cells arise from a parent cell. During B cell clonal expansion, many copies of that B cell are produced that share affinity with and specificity of the same antigen.

Do CD8 T cells undergo clonal expansion?

A simple activation of naive CD8+ T cells requires the interaction with professional antigen-presenting cells, mainly with matured dendritic cells. Once activated, the TC cell undergoes clonal expansion with the help of the cytokine Interleukin-2 (IL-2), which is a growth and differentiation factor for T cells.

How do T cells become activated?

Helper T cells become activated by interacting with antigen-presenting cells, such as macrophages. Antigen-presenting cells ingest a microbe, partially degrade it, and export fragments of the microbe—i.e., antigens—to the cell surface, where they are presented in association with class II MHC molecules.

What causes the clonal expansion of T cells?

What is the importance of clonal expansion?

Clonal expansion not only serves to amplify the number of specific lymphocytes to mount a robust protective response to the pathogen at hand but also results in selection and differentiation of the responding lymphocytes to generate a multitude of cell fates.

Is the example of clonal selection?

Clonal selection theory of lymphocytes: 1) A hematopoietic stem cell undergoes differentiation and genetic rearrangement to produce 2) immature lymphocytes with many different antigen receptors. Those that bind to 3) antigens from the body’s own tissues are destroyed, while the rest mature into 4) inactive lymphocytes.

Why is clonal expansion important?

In both innate and adaptive lymphocytes, clonal expansion is a critical process for host defence by amplifying lymphocytes specific to the invading pathogen. Furthermore, accompanying the robust proliferation of activated lymphocytes is a differentiation programme that results in a multitude of cell fates.

What happens immediately after a lymphocyte becomes activated?

lymphocyte activation stimulation of lymphocytes by specific antigen or nonspecific mitogens resulting in synthesis of RNA, protein, and DNA and production of lymphokines; it is followed by proliferation and differentiation of various effector and memory cells.

When does the clonal expansion of T cells occur?

The clonal expansion of T cells occurs after the T cells have encountered an antigen presented by any of the MHC molecules.

Which is an example of a clonal expansion?

Clonal expansion is the enlargement in the number of competent B cells or T cells with the same antigenic specificity as the progenitor (parent) B cell or T cell. Such B or T cells arise from the same clone of B or T lymphocytes.

When was the clonal expansion of the immune system discovered?

What is clonal expansion? The explosive increase in the number of lymphocytes, both B cells and T cells, from just a few to millions in the presence of an infection was discovered in the 1950s. The process, called clonal expansion, is what gives the adaptive immune system its extraordinary might and specificity.

How is the expansion of a B cell controlled?

Clonal expansion is the enlargement in the number of competent B cells or T cells with the same antigenic specificity as the progenitor (parent) B cell or T cell. Such B or T cells arise from the same clone of B or T lymphocytes. The expansion of B and T cells in this fashion is controlled by the clonal selection theory.