What is bystander activation?

Bystander activation, i.e., activation of T cells specific for an antigen X during an immune response against antigen Y may occur during viral infections.

What is bystander damage immunology?

The term bystander effect describes the ability of cells affected by irradiation to convey manifestations of damage to other cells not directly targeted for irradiation. An irradiated cell can send out a signal and induce a response in a cell whose nucleus was not directly hit by radiation.

What is bystander T cells?

Bystander T cell (in the context of infections): a T cell is considered a bystander T cell if it lacks disease-relevant specificity but is activated in a TCR-independent manner.

What is bystander effect in gene therapy?

Because this therapeutic gene cannot be easily introduced into the whole cell population of a tumor, the successful eradication of tumors depends on a phenomenon called the “bystander effect,” by which the introduced gene can affect even cells in which it is not itself present.

When are cytotoxic T cells activated?

For example, cytotoxic T cells have been shown to become activated when targeted by other CD8 T cells leading to tolerization of the latter. 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.

When 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 is bystander effect radiation?

Radiation-induced bystander effect is defined as the induction of biological effects in cells that are not directly traversed by a charged particle but are in close proximity to cells that are, or have received signals from, these irradiated cells.

What is the bystander effect microbiology?

The bystander effect refers to the biological response of a cell resulting from an event in an adjacent or nearby cell. Such effects depend on intercellular communication and amplify the consequences of the original event.