Immunology: Natural Immunity Characteristics and Determinants

Comprehensive vocabulary flashcards covering the history, characteristics, mechanisms, and determinants of natural immunity based on the lecture notes.

Immunis

A Latin term meaning free from or exempt, which is the root of the word immunology.

Immunity (Hassana)

Protection from any infection regardless of its source, whether bacterial, fungal, parasitic, or viral.

Edward Jenner

The first physician to practice programmed injection of cowpox components to protect individuals from smallpox.

Louis Pasteur

Considered the first experimental immunologist; he developed attenuated vaccines for chicken cholera, anthrax, and rabies.

Joseph Meister

The first person treated with Pasteur's rabies vaccine, receiving $13$ injections in his navel.

Natural Immunity

A genetically determined defense system present from birth that is non-specific, immediate, and does not form immune memory.

Acquired Immunity

A specific immune response that is developed after exposure to a pathogen and possesses characteristics opposite to natural immunity.

Determinants of Natural Immunity

Factors including species and strains, individual differences and age, sex hormones, and nutritional factors.

Species Resistance Examples

Rats are completely resistant to Diphtheria, while humans and guinea pigs are not; dogs are generally not susceptible to the common cold virus.

Genetic Impact on Tuberculosis

If one homozygote twin is infected with TB, the chance for the second twin is $75\%$, compared to $25\%$ in heterozygote twins.

Toll-like Receptors (TLRs)

Receptors on Antigen Presenting Cells (APCs) that trigger signal proteins to induce inflammation and guide natural and adaptive immune responses.

Intraepithelial T-Lymphocytes

A type of T-cell located in the epithelium of the skin and digestive tract that carries $\gamma \delta$ receptors and monitors for invading microbes.

CD1 (Cluster of Differentiation 1)

Molecules similar to MHC class I that present lipid antigens to intraepithelial T-lymphocytes and NK-T cells.

NK-T Cells

Cells that bridge the natural and adaptive immune systems, recognizing peptide, lipid, and sugar antigens presented on $CD1$.

B1 Cells

Special B-lymphocytes found in the peritoneum that produce natural $IgM$ antibodies against microbial polysaccharides.

Lysozyme (Muramidase)

An alkaline protein enzyme found in tears and sweat that kills Gram-positive bacteria by cleaving peptidoglycan in their cell walls.

Properdin System

A macroglobulin in serum that activates the complement system via the alternative pathway to destroy Gram-negative bacteria and viruses.

Conglutinins

Elongated molecules in the serum of ruminants that help aggregate antigen-antibody complexes bound to the complement.

Basic Polypeptides

Tissues and blood-derived proteins like Spermine and Spermidine that have toxic activity against bacilli like Staphylococcus.

Acute Phase Proteins

Proteins like $CRP$ (C-Reactive Protein) whose serum concentration increases up to $1000$ times during infection or inflammation.

Interferon (IFN)

Antiviral proteins produced by infected cells that bind to neighboring healthy cells to inhibit viral $mRNA$ translation and replication.

Endogenous Pyrogen ($L_{1}$)

The substance responsible for increasing body temperature following infection by stimulating prostaglandin synthesis in the hypothalamus.

Inflammation Signs

The clinical process characterized by heat, redness, swelling, pain, and loss of function.

Complement System

A group of heat-labile serum proteins that mediate opsonization, cellular activation, and cell lysis to remove foreign matter.

Complement Activation Pathways

The three methods of activation: Classical pathway, Alternative (Substitute) pathway, and the Lectin (Mannose) pathway.