Microbiology and Immunology Definitions

Incidence

Number of new cases of a disease in a given area during a given period of time.

Prevalence

Number of total cases of a disease in a given area during a given period of time.

Inflammation

Non-specific response to tissue damage from various causes.

Acute inflammation

An immediate response to injury.

Adaptive immunity

The body’s ability to recognize and defend itself against distinct invaders and their products.

Exogenous Antigens

Include toxins and other components of microbial cell walls, membranes, flagella, and pili; present outside of our cells.

Endogenous antigens

Produced by microbes that reproduce inside a body’s cells.

Autoantigens

Derived from normal cellular processes.

Interleukins

Signal among leukocytes.

Chemokines

Chemotactic cytokines that signal leukocytes to move.

Contamination

Presence of microbes in or on the body.

Infection

The successful invasion of a host by an pathogenic organism.

4 Portals of Entry

Skin, mucous membranes, placenta, and parenteral route.

Adhesion

Process by which microorganisms attatch themselves to cells.

Adhesion Factors

Specialized attachment molecules and surface structures that pathogens use to stick to host cells.

Pathogens

Microorganisms that are harmful to the human body.

Virus

Infectious agent that consists of nucleic acids (genetic material), wrapped in a capsid (protein shell).

4 Types of Symbiosis

Mutualism, commensalism, amensalism, and parasitism.

Mutualism

Symbiotic relationship where both organisms benefit from another, sometimes to the point that they cannot live without one another.

Commensalism

Symbiotic relationship where one organism benefits, but the other is neither harmed nor benefited.

Amensalism

Symbiotic relationship where one organism is harmed, but the other is neither harmed nor benefitted.

Parasitism

Symbiotic relationship where one organism benefits, while the other is harmed.

2 Types of Microbiome of Humans (Normal Microbiota)

Resident microbiota, and transient microbiota.

Resident Microbiota

Normal microbiota throughout the entire lifespan of a human.

Transient Microbiota

Remains in a host for a short period of time.

Axenic

Free of microorganisms.

Opportunistic Pathogens

Normal microbiota that cause disease under certain circumstances.

Reservoirs of Infection

Sites where pathogens are maintained as a source of infection.

3 Types of Reservoirs

Animal reservoir, human reservoir, and non

Zoonoses

Animal reservoir that naturally spreak from animal host to humans.

Types of Zoonoses

Helminthic, protozoan, fungal, bacterial, and viral.

Human Carriers

Asymptomatic infected individuals.

Adhesins

Specialized surface proteins that allow them to stick to host cells.

Disease

Results if the invading pathogen alters normal body functions. Also referred to as morbidity.

Symptoms

Subjective characteristics of disease, felt only by the patient.

Signs

The observed and measured aspects of disease.

Syndrome

A collection of symptoms and signs that characterize a disease or an abnormal condition.

Asymptomatic/Subclinical Infections

Lacking symptoms,but may still have signs of infection.

Etiology

Study of the cause of disease.

2 Virulence Factors of Infectious Agents

Pathogenicity and Virulence.

Pathogenicity

Ability of a microorganism to cause disease.

Virulence

Degree of pathogenicity.

5 Virulence Factors that Contribute to Virulence

Adhesion factors, biofilms, extracellular enzymes, toxins, antipagocytic factors.

Lethal Dose

LD50 is the number of cells of a pathogen that kills 50% of the animals in a test group.

Extracellular Enzymes

Secreted by a pathogen, dissolves structural chemicals in the body, helps pathogen maintain infection, invade, and avoid body defenses.

Toxins

Chemicals that harm tissues or trigger host immune responses that cause damage.

Toxemia

Refers to the presence of toxins in the bloodstream.

2 Types of Toxins

Exotoxins and endotoxins.

Endotoxins

Toxic lipopolysaccharide substances (Lipid A) that are part of the outer membrane of the cell wall of gram-negative bacteria.

Exotoxins

Proteins produced inside pathogenic bacteria, most commonly-gram-positive bacteria.

Pyrexia

Fever

Gram-positive

A bacterium that has a thick cell wall that holds a purple dye during a laboratory test.

Gram-negative

A bacterium that does not hold a purple dye during a laboratory test.

Monocytes

Largest leukocytes that leave the circulation, enter tissues, and differentiate into macrophages.

Active Immunization

Administration of antigens so the patient actively mounts an adaptive immune response.

Passive immunotherapy

Individual acquires immunity through the transfer of antibodies formed by immune individuals or animals.

5 Types of Vaccines

Attenuated, inactivated, toxoid, combination, and using recombinant gene technology.

Attenuated Vaccines

Helpful to protect us from something we may have in the future.

2 Methods to Induce Immunity

Active (vaccine) and passive.

Antiserum

Blood containing antibodies.

Hybridomas

Induce immunity in an animal and the animal produces antibodies and the immune cells from it will join up with cancer cells to have the ability to continue produce the antibodies.

Serology

The determination of the presence of specific antigens or antibodies in blood serum.

Serum

Plasma minus clotting proteins.

3 Types of Agglutination Tests

Agglutination, titration

Agglutination

Clumping of insoluble particles.

Precipitation

The aggregation of soluble molecules.

Hemagglutination

Agglutination of red blood cells.

Titration

Serum being tested is serially diluted and tested for agglutinating activity.

Labeled Antibody Tests (Flourescent Immunoassays)

Flourescently labeled antibodies.

Serological Tests

Labeled antibody tests, ELISA, sandwich ELISA, western blot, point-of-care testing, and immunochromatographic assays.

2 Types of Flourescent Immunoassays

Direct and indirect flourescent immunassays.

Direct fluorescent immunoassays

Fluorescent antibodies are used to identify antigens.

Indirect fluorescent immunoassays

Fluorescent antibodies identify antibodies in serum.

ELISA

Stands for enzyme-linked

immunosorbent assay, uses an enzyme as the label, and the reaction of the enzyme withits substrate produces a coloured product, indicating a positive test.

Immunoblot (Western Blot)

Electrophoresis

Point-of-Care Testing

Simple immunoassays that give results in minutes.

4 Situations where the Immune System is Ineffective or Harmful

Allergy/hypersensitivity, immunodeficiency, autoimmune, and graft rejection.

4 Types of Hypersensitivity

Type I (immediate), type II (cytotoxic), type III (immune complex-mediated), and type IV (delayed or cell-mediated).

Hypersensitivity

Any immune response against a foreign antigen exaggerated beyond the norm.

Type I (Immediate) Hypersensitivity

Also known as allergies; localized or systemic reaction that results from the release of inflammatory molecules in response to an antigen (allergens).

2 Steps of Type I (Immediate) Hypersensitivity

Sensitization and degranulation.

Sensitization

Degranulation

Type II (Cytotoxic) Hypersensitivity

Results when cells are destroyed by an immune

response.

Immune Complexes

Triggers release of inflammatory chemicals.

Inflammatory Chemicals

Histamine, kinin, proteases, leukotrienes, prostoglandins.

Rheumatoid Arthritis

Immune complexes deposited in the joint, resulting in the release of inflammatiry chemicals.

Systemic Lupus Erthematosus

Type IV (Delayed or Cell-Mediated)

Hypersensitivity

Inflammation 12–24 hours after contact with certain

antigens