Immunology and Serology Review Flashcards

Comprehensive vocabulary flashcards covering basic immunology, serology, historical milestones, immune mechanisms, and diagnostic testing principles.

Immunology

The study of the reaction of a host when foreign substances are introduced into the body and the study of body defenses such as antigens, antibodies, allergy, and hypersensitivity.

Variolation

The historical practice of deliberately exposing an individual to material from smallpox lesions, such as pulverized powder from a scab, to produce protection against the disease.

Vaccination

A term derived from the Latin word "vacca", meaning "cow", originally used following Jenner's discovery that protection from cowpox generated protection against smallpox.

Attenuation

The process of weakening bacteria or viruses through modifying conditions such as chemical treatment, heat, aging, or repeated in vitro passage in cell culture.

Vaccine

An antigen suspension derived from a pathogen that is administered to healthy individuals to stimulate an immune response and prevent disease through immunization.

Cross-immunity

The phenomenon in which exposure to one agent produces protection against another agent.

Innate Immunity

Also known as natural immunity; the individual’s ability to resist infection by means of normally present, nonadaptive, and nonspecific body functions that lack memory.

Adaptive Immunity

Also known as acquired immunity; a resistance characterized by specificity for each individual pathogen and the ability to remember a prior exposure, resulting in an increased response upon repeated exposure.

Competitive Exclusion

A phenomenon where normal microbial flora in the body keeps pathogens from establishing themselves in specific areas.

Acute Phase Reactants

Normal serum constituents produced by hepatocytes that increase rapidly by at least $25\%$ due to infection, injury, or trauma to the tissues.

C-Reactive Protein (CRP)

A trace constituent of serum that acts like an antibody by being capable of opsonization, agglutination, precipitation, and activation of complement by the classical pathway; it is the best indicator of acute inflammation.

Phagocytosis

The process observed by Elie Metchnikoff in which foreign objects are surrounded and destroyed by motile cells.

Opsonins

Serum proteins, such as antibodies, $C3b$, and $CRP$, that coat foreign particles to enhance the process of phagocytosis.

Chemotaxins

Chemical messengers that cause cells to migrate in a particular direction.

Pathogen-Associated Molecular Patterns (PAMPs)

Groups of microorganisms characterized by a few large groups of molecules that the innate immune response is able to recognize.

Pattern Recognition Receptors (PRRs)

Receptors of the innate immune system, such as Toll-like receptors ($TLRs$), that recognize pathogen-associated molecular patterns.

Diapedesis

The process by which cells move from the circulating blood to the tissues by squeezing through the wall of a blood vessel.

Haptens

Nonimmunogenic materials that are too small to be recognized alone but can stimulate an immune response when combined with a larger carrier molecule.

Adjuvant

A substance administered with an immunogen, such as aluminum salts, that increases the immune response.

Epitope

Also known as the determinant site; the key portion of the immunogen that binds to the antibody or sensitized $T\text{ cell}$.

Paratope

The part of an antibody that binds to the antigenic determinant site (epitope).

Syngeneic graft

Also called an isograft; the transfer of cells or tissues to a genetically identical individual of the same species, such as between identical twins.

Xenograft

Also called a heterograft; the transfer of cells or tissues to a member of a different species, such as a pig valve into a human heart.

Titer

The reciprocal of the highest dilution of patient serum in which the antibody is still detectable.

Hybridoma

An immortal cell capable of producing indefinite sequence of nucleotides, formed by fusing a plasma cell with a non-secreting myeloma cell.

Complement System

A humoral mechanism of nonspecific immune response consisting of $14$ distinct serum proteins that proceed in a cascading sequence of activation, resulting in cell lysis.

Anaphylatoxin

A small peptide, such as $C3a$, $C4a$, or $C5a$, that causes increased vascular permeability, contraction of smooth muscle, and histamine release.

Cytokines

Chemical messengers that regulate the immune system by influencing the hematopoietic and immune systems through activation of cell-bound receptors.

Pleiotropy

A property of cytokines where a single cytokine can have many different actions.

Atopy

A term derived from the Greek word "atopos", referring to an inherited tendency to develop classic allergic responses to naturally occurring inhaled or ingested allergens.

Infectivity

An organism’s ability to establish an infection through person-to-person spread.

Pathogenicity

The inherent capacity of an organism to cause disease, determined by its genetic makeup.

Virulence

A quantitative trait referring to the extent of damage or pathology caused by an organism.

Reagin

A non-treponemal antibody of the $IgG$ or $IgM$ class that forms against cardiolipin, a lipid material from damaged cells, used in syphilis screening.

Flocculation

A specific type of precipitation that occurs over a narrow range of antigen concentrations, often appearing as macroscopic agglutination in tests like $VDRL$ and $RPR$.

Affinity

The initial force of attraction between a single $Fab$ site on an antibody and a single epitope on an antigen.

Avidity

The sum of all attractive forces between an antigen and an antibody, representing the overall strength of binding.

Dane particle

The term for a complete $HBV$ (Hepatitis B Virus) virion.

Bence Jones protein

$Light\text{ chains}$ found in the urine of patients with Multiple Myeloma.

Koplik spots

Spots that appear on the mucous membranes of the inner cheeks or lips, characteristic of rubeola (measles).