Clinical Pathology: Serology, Immunology, and Semen Evaluation

Vocabulary flashcards covering clinical pathology topics including serology, immunology, hypersensitivity reactions, diagnostic testing mechanisms, and semen evaluation based on the lecture notes.

Serology

The scientific study of blood serum and fluid components of the blood, primarily referring to the diagnostic identification of antigens, antibodies, and immune responses in serum.

Antigen

A foreign substance or particle (usually a protein or lipoprotein, such as bacterial cell walls, toxins, or viruses) that can trigger or provoke an immune response in the body.

Antibody

A large protein molecule (also known as an immunoglobulin) produced by specialized B lymphocytes in response to a specific antigen.

Innate Immunity

The non-specific, quick-response immune defense system that includes physical barriers (skin, mucous membranes), chemical secretions, inflammatory responses, phagocytes, natural killer cells, and the complement system.

Adaptive Immunity

The specific, antigen-targeted immune defense system that reacts after exposure to a pathogen, divided into humoral immunity (B cells) and cell-mediated immunity (T cells).

Complement System

A series of blood proteins playing a role in innate and adaptive immunity by combining with antigen-antibody complexes, enhancing phagocytosis, or forming membrane attack complexes that cause cell lysis.

IgM

The 'first responder' immunoglobulin and second most common antibody class; produces the primary immune response to new antigens, neutralizes viruses, and is the antibody type made by newborns.

IgG

The most common antibody type in the body; coats antigens to enable their destruction by macrophages and transfers from mother to fetus.

IgE

An immunoglobulin involved in allergic reactions, skin and food allergies, inflammation, and parasitic infection defense by attaching to mast cells and triggering histamine release.

IgA

An immunoglobulin secreted at mucosal surfaces (respiratory and gastrointestinal tracts) that binds to antigens and prevents viruses and bacteria from attaching to epithelial cells.

IgD

An immunoglobulin present in low concentrations in primates, rodents, and dogs, and not found in all species.

Humoral Immunity

The branch of adaptive immunity mediated by B lymphocytes, which mature in the bone marrow and differentiate into memory B cells or antibody-secreting plasma cells.

Cell-Mediated Immunity

The branch of adaptive immunity driven by T lymphocytes maturing in the thymus, including Helper T cells (which regulate immunity via cytokines) and Cytotoxic T cells (which attack infiltrative or infected cells).

Anergy

A mechanism of immunologic tolerance wherein lymphocytes are rendered unable to respond when they encounter self-antigens.

Apoptosis

Programmed cell death that occurs in lymphocytes upon encountering self-antigens to maintain immunologic tolerance.

Passive Immunity

Immunity acquired by receiving preformed antibodies, such as a newborn ingesting maternal colostrum or an animal receiving an antibody injection.

Active Immunity

Immunity developed when an animal's own immune system responds to an antigen, such as through exposure or immunization/vaccination.

Sensitivity

The ability of a diagnostic test to correctly identify true positives and detect disease presence, thereby minimizing false negatives.

Specificity

The ability of a diagnostic test to correctly identify true negatives and rule out disease absence, thereby minimizing false positives.

ELISA (Enzyme Linked Immunosorbant Assay)

An immunoassay testing technique using monoclonal antibodies bound to a membrane or well to form antigen-antibody complexes detected via enzyme-labeled secondary antibodies and a color-changing substrate.

Rapid Immunomigration (RIM)

A lateral flow immunoassay where a sample containing antigens flows through a porous strip with embedded antibodies, producing a colored band for a positive reaction.

Agar Gel Immunodiffusion (AGID)

A diagnostic technique (such as the Coggins test for Equine Infectious Anemia) where antigens and antibodies migrate toward each other through an agar gel matrix to form a visible line of precipitation.

Agglutination

The aggregation or clumping of suspended cells or coated particles caused by antigen-antibody complex formation.

Titer

An indirect quantitative measurement of antibody concentration in serum, defined as the highest serum dilution capable of producing a positive test reaction or agglutination.

Autoimmune Disease

A disease state resulting from a breakdown in immunologic tolerance, causing the animal's immune system to produce antibodies directed against its own tissues.

Type I Hypersensitivity

An immediate IgE-mediated reaction leading to mast cell degranulation and histamine release within one hour of exposure (e.g., anaphylaxis, atopy).

Type II Hypersensitivity

An antibody-mediated cytotoxic reaction (involving IgG or IgM) directed against an animal's own self-cells or extracellular matrix components (e.g., IMHA, ITP, blood transfusion reactions).

Type III Hypersensitivity

An immune-complex-mediated reaction occurring when antigen-antibody precipitates deposit in tissue blood vessels and activate complement, attracting neutrophils (e.g., SLE, glomerulonephritis, IMPA).

Type IV Hypersensitivity

A delayed T-cell-mediated immune reaction occurring 24 hours or more after antigen exposure (e.g., contact hypersensitivity, tuberculin test, organ transplant rejection).

Tuberculin (Tb) Test

A cell-mediated intradermal skin test used in cattle and primates to detect exposure to Mycobacterium spp. bacteria.

Primary Sperm Defects

Serious sperm abnormalities occurring during the process of spermatogenesis, typically involving the head and mid-piece of the spermatozoon.

Secondary Sperm Defects

Sperm abnormalities occurring during storage within the epididymis or during sample collection and handling, commonly affecting the tail.