Laboratory Management: Overview of Immunology and Serology

Vocabulary flashcards covering immunology concepts including historical milestones, innate vs. adaptive immunity, acute-phase reactants, leukocyte characteristics, tissue macrophages, Toll-like receptors, phagocytosis, and signs of inflammation.

Immunology

The study of how our bodies recognize foreign objects, interact with them, and protect the body.

Self vs. Non-Self

Self refers to molecules and tissues that naturally belong to the body, whereas Non-Self refers to foreign entities such as bacteria, viruses, and fungi.

Variolation

A practice developed by the Chinese in the 1500s involving deliberate exposure of an individual to material from smallpox lesions.

Edward Jenner

The scientist who introduced smallpox vaccination in the 1700s using cowpox material, establishing the concept of cross-immunity.

Cross-immunity

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

Ellie Metchnikoff

The scientist who observed motile cells surrounding foreign objects in transparent starfish larvae, introduced cellular immunity, and named the process phagocytosis.

Louis Pasteur

The scientist who introduced live attenuated vaccines for chicken cholera and anthrax (1880-1881), and developed an anti-rabies vaccine in 1885 using rabid animal spinal cords.

Almoth Wright

The scientist who linked cellular immunity and humoral immunity by demonstrating that the immune response involves both cellular and humoral elements.

Innate Immunity

Built-in, non-specific immunity present at birth that provides an immediate first and second line of defense using pre-formed components, lacking immunologic memory.

Acquired Immunity

A highly specific third-line defense that develops after antigen exposure, characterized by memory, inducibility, specialization, self-limitation, and increased response upon repeated exposure.

Spermin

A pH-dependent polyamine found in semen that inhibits the growth of gram-positive bacteria.

Defensins

Cationic proteins present in human neutrophils that kill microbes by interacting directly with microbial membranes.

Interferons (IFN)

Serum molecules that increase rapidly during inflammatory disease to signal neighboring cells and block viral translation; includes Alpha IFN, Beta IFN, and Gamma IFN.

Acute Phase Reactants

Plasma proteins produced by the liver whose concentrations change rapidly in response to inflammation to limit tissue injury and infection.

C-reactive protein (CRP)

An acute-phase reactant with a response time of $6-10\,\text{hr}$, a normal concentration of $0.5\,\text{mg/dL}$, and up to a $1000\times$ increase during inflammation; functions in opsonization and complement activation.

Serum amyloid A

An acute-phase protein with a response time of $24\,\text{hr}$ and normal concentration of $3.0\,\text{mg/dL}$ that increases up to $1000\times$ to promote the removal of cholesterol.

Haptoglobin

An acute-phase protein with a normal concentration of $40-200\,\text{mg/dL}$ that increases $2-10\times$ to bind free hemoglobin and limit oxidative damage.

Ceruloplasmin

An acute-phase protein with a normal concentration of $20-40\,\text{mg/dL}$ that increases $2\times$ after $48-72\,\text{hr}$ to bind copper and oxidize iron.

Neutrophil

The most abundant leukocyte ($50-70\%$ of circulating WBCs), capable of diapedesis and phagocytosis, containing primary, secondary, and tertiary granules.

Selectin

A molecule that enhances the adherence of neutrophils to endothelial cells during diapedesis.

Eosinophil

A leukocyte constituting $1-3\%$ of circulating WBCs that increases during allergic reactions and parasitic infections, neutralizing basophils and mast cells.

Basophil

A leukocyte comprising less than $1\%$ of circulating WBCs, involved in immediate hypersensitivity reactions, containing granules with histamine, heparin, and ECF.

Mast Cell

A connective tissue cell of mesenchymal origin that resembles basophils and is involved in immediate hypersensitivity reactions, containing acid phosphatase, alkaline phosphatase, and protease.

Monocyte

The largest circulating WBC ($4-10\%$ of WBCs), featuring a ground-glass appearance and horseshoe-shaped nucleus, which differentiates into tissue macrophages.

Diapedesis

The process by which white blood cells squeeze through blood vessel walls to migrate to infected tissues.

Alveolar Macrophage

A differentiated macrophage localized specifically within the lungs.

Kupffer Cell

A differentiated macrophage localized specifically within the liver.

Microglial Cell

A differentiated macrophage localized specifically within the brain.

Histiocyte

A differentiated macrophage localized within connective tissue.

Dendritic Cell

The most phagocytic cell in tissue, resembling nerve cell dendrites, responsible for processing antigens and presenting them to T-helper cells.

Toll-like Receptors (TLRs)

Receptors originally discovered in Drosophila that recognize microbial molecules; found in highest concentrations on monocytes, macrophages, and neutrophils.

TLR1, TLR2, and TLR4

Specific Toll-like receptors that bind to Gram-positive bacteria (TLR1), Mycobacteria (TLR2), and Gram-negative bacteria (TLR4).

Indirect Phagocytosis

Phagocytosis occurring via opsonin receptors binding to targets coated with CRP, complement, or antibodies.

Oxygen-Dependent Phagocytic Killing

Microbial destruction utilizing a lysosomal respiratory burst (via NADPH oxidase and the hexose monophosphate shunt) and halogenation catalyzed by myeloperoxidase.

Inflammation

The overall protective reaction of the body to tissue injury or invasion by an infectious agent.

Cardinal Signs of Inflammation

The five signs of inflammation: Rubor (redness), Tumor (swelling), Calor (heat), Dolor (pain), and Functio laesa (loss of function).

Humoral-Mediated Immunity

Adaptive immunity mediated by B lymphocytes and circulating antibodies, serving as the primary defense against bacterial infections.

Cell-Mediated Immunity

Adaptive immunity mediated by T lymphocytes through direct cell contact or cytokine secretion, serving as defense against intracellular organisms, viruses, fungi, tumor antigens, and graft rejection.