Immunology Chapter Overview

Regulatory T cells (Tregs) are essential for suppressing excessive immune responses, preventing autoimmune reactions, and maintaining immune tolerance.

The CD4 molecule, found on helper T cells, specifically binds to MHC Class II molecules on antigen-presenting cells. This interaction is crucial for initiating an immune response.

IgA is the predominant immunoglobulin found in mucosal secretions, such as those in the respiratory tract, providing the first line of defense against pathogens entering the body.

The immunological synapse is the specialized contact point formed between a T cell and an antigen-presenting cell. It allows for efficient antigen recognition and signaling, leading to an immune response.

Cytotoxic T cells (T-killers) recognize infected cells by detecting viral antigens presented on MHC Class I molecules, enabling them to directly kill infected cells.

Type I interferons (alpha and beta) play a crucial role in anti-viral immunity by activating immune cells and inhibiting viral replication within infected cells.

MHC Class I molecules are found on all nucleated cells and are involved in presenting intracellular antigens to cytotoxic T cells.

MHC Class II molecules are found on antigen-presenting cells (APCs), such as macrophages and dendritic cells, and present extracellular antigens to helper T cells.

The immune system's first line of defense, acting immediately and without specific recognition of pathogens.

A type of immune response that is specific to a particular pathogen and involves the development of memory cells.

A system of proteins and other molecules that help to destroy pathogens and regulate the immune response.

A complex series of events that occurs in response to tissue injury or infection, involving the release of chemicals and the recruitment of immune cells.

A cell type that lacks MHC Class I molecules, which are typically present on healthy cells. This absence triggers NK cell activation.

A surface marker that is specific to B cells and is used to identify and isolate them.

A type of T helper cell that promotes the production of antibodies, particularly in the humoral immune response.

Pattern recognition receptors on immune cells that recognize pathogen-associated molecular patterns (PAMPs).

A cytokine that is important for promoting the production of interferon-gamma, which activates macrophages and T cells.

Immunoglobulins that have been shown to play roles in targeting and neutralizing tumor cells.

Antigenic molecules present on tumor cells that may not be recognized or targeted effectively by the immune system.

A molecule that regulates complement activation by accelerating the decay of C3 and C5 convertases, preventing damage to host cells.

A type of tolerance that can be formed later in life (newborn and adulthood), playing a role in maintaining immune homeostasis.

The process of transporting immunoglobulins, such as IgA, across epithelial cells into mucosal secretions.

Cells capable of engulfing and destroying pathogens and other foreign particles.

A condition arising when an Rh-negative mother develops antibodies against Rh-positive fetal red blood cells, leading to destruction of the fetus's red blood cells.

Interleukin-5 (IL-5) is a crucial cytokine in allergic reactions, stimulating the activation and recruitment of eosinophils, which are white blood cells that contribute to inflammation.

The process of gene recombination during B cell development generates a vast diversity of antibodies by rearranging gene segments that encode the antigen-binding regions of antibodies.

Hybridoma technology is a technique used to produce monoclonal antibodies. It involves fusing a B cell, which produces a specific antibody, with a myeloma (cancer) cell, which has immortality.

Cytotoxic T cells (T-killers) eliminate infected or cancerous cells by releasing perforin, a protein that forms pores in the target cell's membrane, and granzyme, an enzyme that triggers programmed cell death (apoptosis).

Humoral factors are components of the nonspecific immune system that help defend the body against infections. They act in the body fluids, unlike the specific immune response, which involves antibodies (immunoglobulins) produced by B cells.

Immunoglobulins are antibodies that are produced by B cells as part of the specific immune response. They do not play a role in the nonspecific defense system.

Toll-like receptors (TLRs) are pattern recognition receptors found on various immune cells. These receptors recognize and bind to pathogen-associated molecular patterns (PAMPs) found on pathogens, triggering the activation of those immune cells.

Macrophages, dendritic cells, neutrophils, and B cells are all types of immune cells that can be activated by TLRs. This activation helps initiate innate immune responses to fight infections.

Negative selection in the thymus is a vital process that eliminates self-reactive T cells during T-cell development. This prevents the immune system from attacking the body's own tissues and causing autoimmune diseases.

Light microscopy is a versatile technique that allows scientists to visualize and differentiate various types of leukocytes (white blood cells) in blood smears. This helps determine their relative numbers and identify any abnormalities.

CD markers, like CD3 and CD19, are specific surface receptors that act as markers for identifying different types of lymphocytes. CD3 is associated with T cells, while CD19 is associated with B cells.

Serum immunoglobulin levels serve as an indicator of the humoral immune system's activity. Higher levels usually indicate a strong immune response or current infection, while low levels may suggest an impaired immune response.

ELISA (Enzyme-Linked Immunosorbent Assay) is a common laboratory technique that utilizes labelled antibodies or antigens to detect the presence of specific substances. It is widely used for diagnosing diseases and measuring antibody or antigen levels.

In ELISA, the antigen or antibody is usually labelled with an enzyme. When the target substance is bound, the enzyme catalyzes a reaction that produces a color change, which can be detected and measured.

The EAC-rosette test is a technique used to determine the absolute number of lymphocytes, especially T cells. The test involves mixing lymphocytes with sheep erythrocytes coated with antibodies and complement.

IgE is the specific immunoglobulin responsible for mediating immediate-type hypersensitivity reactions. These reactions occur rapidly and are often associated with allergies (e.g., anaphylaxis).

Delayed-type hypersensitivity (DHT) is a cell-mediated immune response involving T lymphocytes, particularly CD4+ T cells. Unlike immediate-type hypersensitivity, DHT reactions take a little longer to develop (hours to days).

Hypersensitivity reactions can cause tissue damage due to an excessive or inappropriately triggered immune response. This damage can range from mild irritation to severe tissue destruction in severe cases.

Anaphylaxis is a severe, life-threatening allergic reaction that occurs rapidly. It involves the widespread release of histamine and other chemicals from mast cells, leading to symptoms like airway constriction, hives, and shock.