effector

Examples of effector in the following topics:

• Clonal Selection and T-Cell Differentiation

  • Antigens are "selected" to form clones of themselves, both memory and effector.
  • The increased binding affinity may be the reason why memory cells can eliminate a pathogen more rapidly than the original generation of effector cells.
  • Cloned daughter cells differentiate into either effector T cells or memory T cells.
  • Cytotoxic effector T cells are finished, but helper T cells continue to differentiate into individual subsets of helper T cells.
  • Additionally, Th17, which only differentiates from effector cells if certain cytokines are present, are important in regulating and inhibiting T-reg cell activity.

• Classes of T Cells

  • This activation results in the expansion of the antigen-specific lymphocyte pool and the differentiation of these cells into effector and memory cells.
  • Effector cells include helper T cells, and cytolytic or cytotoxic T cells.
  • Memory T cells are an expanded population of T cells specific for antigens that can respond rapidly to subsequent encounter with that antigen and differentiate into effector cell to eliminate the antigen.
  • Distinguish between: naive, effector (helper and cytotoxic), memory and regulatory T cells

• Immunological Memory

  • As B cells and T cells mature into effector cells, a subset of the naïve populations differentiates into B and T memory cells with the same antigen specificities .
  • A memory cell is an antigen-specific B or T lymphocyte that does not differentiate into an effector cell during the primary immune response, but that can immediately become an effector cell on re-exposure to the same pathogen.
  • As the infection is cleared and pathogenic stimuli subside, the effector cells are no longer needed; they undergo apoptosis.
  • If the pathogen is not encountered again during the individual's lifetime, B and T memory cells will circulate for a few years or even several decades, gradually dying off, having never functioned as effector cells.

• Plant Pathogens

  • There are four main bacterial pathogenicity factors: cell wall degrading enzymes, toxins, phytohormones, and effector proteins.
  • Effector proteins: These can be secreted into the extracellular environment or directly into the host cell, often via the Type three secretion system .
  • Some effectors are known to suppress host defense processes.

• Homeostatic Control

  • An effector is any organ or tissue that receives information from the integrating center and acts to bring about the changes needed to maintain homeostasis.
  • The sensors, integrating center, and effectors are the basic components of every homeostatic response.
  • The hypothalamus then sends a message to the heart, blood vessels, and kidneys which all act as effectors in blood pressure regulation.
  • The hypothalamus then signals several effectors to maintain the human body's temperature set point (37 degrees celcius).
  • Conversely if the body's temperature is below the set point, effectors such as muscles will shiver to generate heat and the blood vessels undergo vasoconstriction to retain heat in the body.

• The Synapse

  • A synapse is a structural junction that mediates information transfer from one neuron to the next or from one neuron to an effector cell as in muscle or gland.
  • In the nervous system, a synapse is a structure that permits a neuron to pass an electrical or chemical signal to an effector cell.

• Homeostatic Process

  • Adjustment of physiological systems within the body is called homeostatic regulation, which involves three parts or mechanisms: (1) the receptor, (2) the control center, and (3) the effector.
  • The effector responds to the commands of the control center by either opposing or enhancing the stimulus.
  • For example, during body temperature regulation, temperature receptors in the skin communicate information to the brain (the control center) which signals the effectors: blood vessels and sweat glands in the skin.

• Development of the Dual Lymphocyte System

  • B and T cells) differentiate further after exposure to an antigen; they form effector and memory lymphocytes.
  • Effector lymphocytes function to eliminate the antigen, either by releasing antibodies (in the case of B cells), cytotoxic granules (cytotoxic T cells) or by signaling to other cells of the immune system (helper T cells).

• Adaptive Immunity and the Immunoglobulin Superfamily

  • Antibodies or Immunoglobulins bind antigens in the recognition phase and the effector phase of humoral immunity.
  • These activated B cells produce a soluble form of immunoglobulin that triggers effector mechanisms to eliminate antigens.

• Macrophages

  • In the effector phase of cell-mediated immunity, differentiated effector T cells recognize microbial antigens on phagocytes and activate the macrophages to destroy these engulfed microbes.