Immunology Concepts and Techniques

Activated lymphocytes that multiply rapidly in response to a specific antigen.

A type of laboratory test used to measure the amount of complement protein components in the blood.

A test used to assess the activity of T-lymphocytes and their ability to respond to antigens.

Therapeutic serum derived from human donors who have been immunized against a specific pathogen.

Immature neutrophils, often seen during bacterial infections, particularly those with pus formation.

The primary type of white blood cell involved in fighting bacterial infections and inflammatory processes with pus.

The first antibody to be produced during an immune response, often detected in the early stages of infection, making it useful for diagnosis.

A diagnostic tool used to detect the presence of specific antibodies in the blood sample, particularly early in an infection, by looking for the IgM antibody class.

A family of intracellular receptors that detect microbial components, primarily found in the cytoplasm of cells.

The theory that explains the specificity of the immune response by proposing that each lymphocyte recognizes a unique antigen and proliferates to produce clones of antibody-producing cells.

The theory that focuses on the role of antibodies produced by specialized cells in combating infections.

The main function of the immune system is to recognize and eliminate foreign pathogens and harmful substances, protecting the body from disease.

A multiprotein complex that is formed in response to cellular stress, including infection, leading to inflammation and programmed cell death (pyroptosis).

Specialized cells found in the medulla of the thymus, which are involved in T-cell development and regulation.

The process of lymphocyte production and maturation, which occurs in the central lymphoid organs, mainly the thymus and bone marrow.

A family of intracellular receptors that detect viral RNA in the cytoplasm, triggering antiviral responses.

The second encounter with an antigen, characterized by a more rapid and intense response due to the presence of memory cells.

A hormone produced by the thymus, which plays a crucial role in promoting T-cell maturation and differentiation.

An enzyme abundant in macrophages and neutrophils, known for its ability to break down bacterial cell walls by targeting muramic acid.

A type of white blood cell (granulocyte) that plays a crucial role in protecting against large parasitic infections, such as helminths.

An antigen found in the bacterial cell wall, commonly responsible for the somatic (O) serotype of bacteria.

An essential adaptor protein that is involved in the activation of signaling pathways for most Toll-like receptors, leading to the initiation of immune responses.

A protein produced mainly by liver hepatocytes during acute-phase responses, acting as a marker of inflammation.

CLR receptors recognize and bind to carbohydrate structures on microbial surfaces, triggering an immune response.

TLR5 is a specific type of toll-like receptor found on immune cells that recognizes bacterial flagellin, a protein found in the whip-like appendages of bacteria.

The primary immune response is slower and less intense compared to a secondary response, but it results in the generation of memory cells that provide long-lasting immunity.

Following phagosome formation, the next step in phagocytosis is the fusion of the phagosome with lysosomes. This forms a phagolysosome, which contains powerful enzymes to degrade the engulfed pathogen.

Antigenicity refers to the ability of a substance to bind to specific receptors on immune cells and trigger an immune response. This ability is determined by the chemical structure of the antigen.

Mycobacterium tuberculosis, the bacterium responsible for tuberculosis, can evade destruction by preventing the fusion of phagosomes with lysosomes, allowing it to survive within phagocytes.

T-lymphocytes are divided into subpopulations based on their functions and surface markers. They start as CD4+ T helper cells, which can then differentiate into other subtypes, such as CD8+ cytotoxic T cells and regulatory T cells.

Macrophages, specialized immune cells that engulf and destroy pathogens, cooperate with T cells and B cells during primary antigen recognition. They present antigens to T cells and work with B cells to produce antibodies.

Some pathogens have evolved strategies to avoid phagocytosis. One of these strategies is the secretion of superoxide dismutase, an enzyme that neutralizes reactive oxygen species, which are crucial for killing engulfed pathogens.

The spleen, a major organ of the immune system, is responsible for antigen presentation, development of a specific immune response, and neutralization of antigens.

A complete antigen consists of two parts, the carrier molecule and the epitope. The epitope, also known as the antigenic determinant, is the part that binds to immune receptors and triggers an immune response.

Antigens are classified based on their structure into two main groups: complete antigens and incomplete antigens. Complete antigens can elicit an immune response on their own, while incomplete antigens, also known as haptens, require a carrier molecule to become immunogenic.

The alternative pathway of complement activation is triggered by the presence of lipopolysaccharides (LPS), which are found on the outer membrane of gram-negative bacteria.

Macrophages and neutrophils are the primary phagocytic cells in the immune system, engulfing and destroying foreign invaders like bacteria and viruses.

M-cells are specialized cells located in the mucosal-associated lymphoid tissue (MALT). They transport antigens across the epithelium into the MALT, facilitating antigen presentation to immune cells.

Mucosa-associated lymphoid tissues (MALT) are specialized immune tissues found in mucosal linings, like the gut and respiratory tract. They provide the first line of defense against pathogens entering the body through these surfaces.

Alpha-fetoprotein (AFP) is a protein produced by the developing fetus. Elevated levels of AFP in an adult can indicate the presence of certain types of cancer, particularly those originating from embryonal cells.

Secretory IgA is an antibody found in mucosal secretions, like saliva, tears, and breast milk. It helps neutralize pathogens and prevent them from entering the body.

Specificity refers to the ability of an antibody to bind only to a specific antigen, like a key fitting into a specific lock.

TGF-β is a cytokine that plays a crucial role in promoting the production of IgA antibodies, which are essential for mucosal immunity.

Syncytiotrophoblasts are cells that form the outer layer of the placenta. They have Fc receptors that allow the transfer of IgG from the mother's blood to the fetus.

Plasmapheresis is a procedure that removes certain components of the blood, including autoantibodies, which are antibodies that mistakenly attack the body's own tissues.

IL-2 is a cytokine that stimulates the growth and activation of cytotoxic T lymphocytes, which are specialized immune cells that destroy infected or abnormal cells.

MHC Class II molecules are found on the surface of antigen-presenting cells (APCs), such as macrophages and dendritic cells. They present processed antigens to CD4+ T cells, initiating an immune response.

Cytotoxic T lymphocytes (CTLs) induce programmed cell death, or apoptosis, in target cells. They are essential for eliminating virus-infected cells and cancer cells.

Interferons are a group of cytokines produced mainly by leukocytes, particularly dendritic cells. They play a crucial role in antiviral immunity.

IgG is the most abundant immunoglobulin in the blood and is also the only one that can cross the placenta to provide passive immunity to the developing fetus.

The Fc fragment interacts with receptors on innate immune cells, such as macrophages and neutrophils, activating them to engulf and destroy pathogens or damaged cells.

NK cells are part of the innate immune system and are known for their ability to directly kill target cells without the need for prior sensitization. They play a significant role in immune surveillance against infections and cancer.

MHC Class II molecules and co-stimulatory molecules like CD80 are crucial signals for activating naive CD4+ T cells. This activation process ensures that T cells are properly primed to respond to specific antigens.