rest of 16/some of 19

Comprehensive vocabulary flashcards covering adaptive immunity (T-cell and B-cell responses, immunoglobulins), immunopathology and hypersensitivities, vaccine technologies, and bacterial skin and soft-tissue infections (Staphylococcus, Pseudomonas, Clostridium, and Streptococcus).

T-Cells (T lymphocytes) - Cell-Mediated Immunity

-mature in the thymus

-utilize T-cell receptors (TCRs).

- many types:

• Helper T cells (Th) - CD4 receptors

  • Th1 - interact with Tc cells (and macrophages)

  • Th2 - interact with B cells

• Cytotoxic T-Cells (Tc) - CD8 Receptors

Helper T-Cells ($T_H$)

T-lymphocytes characterized by CD4 surface receptors ($\text{CD4}^+$); CDC4 + T cells —> HIV = on clinical reports

$T_H1$ Cells

A subtype of helper T-cells that interacts with cytotoxic T-cells ($T_C$) and macrophages to eliminate intracellular pathogens such as viruses; inside cell

$T_H2$ Cells

A subtype of helper T-cells that interacts with B-cells, assists in fighting parasitic infections, and participates in allergic reactions.

Cytotoxic T-Cells ($T_C$)

T-lymphocytes bearing CD8 receptors that interact directly with cells presenting specific foreign antigens to destroy them.

Other Cells:

• Gamma-Delta T cells

  • Recognize PAMPs —> molecules that you commonly find on pathogens

• Natural Killer (NK) Cells

  • Antibody-dependent cellular cytotoxicity (ADCC)

Gamma-Delta ($\gamma\delta$) T-Cells

Rapid-response T-cells that defend peripheral tissues against infections and abnormal cells by recognizing pathogen-associated molecular patterns (PAMPs).

Pathogen-Associated Molecular Patterns (PAMPs)

Conserved molecular structures commonly found on microbial pathogens that are recognized by immune cells, including gamma-delta T-cells.

Natural Killer (NK) Cells

Innate immune lymphocytes capable of destroying virus-infected and abnormal host cells without requiring prior exposure to the pathogen.

Antibody-Dependent Cellular Cytotoxicity (ADCC)

A mechanism in which effector cells (such as NK cells) recognize antibody-coated target cells and directly kill them.

Antigen (Ag)

• Also known as an immunogen

• Must be of a certain size; big antigen has parts to it

• Usually proteins (or large polysaccharides) —> have blood type been you have polysaccharide antigen

• Epitope (antigenic determinant)

• Happen

• Superantigens

Epitope

Also termed an antigenic determinant; the precise structural region on an antigen recognized and bound by a specific antibody or immune cell receptor.

Hapten

A small molecule that is not immunogenic on its own and can only stimulate an immune response when conjugated to a larger carrier protein.

Superantigens

Bacterial virulence factors that forcefully overstimulate T-cells non-specifically, provoking a massive release of cytokines that leads to severe tissue damage, systemic inflammation, and toxic shock.

Antibody (Ab)

• Also known as an immunoglobulin (Ig)

• Proteins that bind to (epitopes of) antigens

• VERY specific —> only bind to your antigen or similar

• Made by specific B cells (when stimulated)

• Antibody Titer

Antibody Titer

A laboratory measurement quantifying the concentration of detectable, active antibodies directed against a specific antigen within the blood.

Antibody composed of….(tetrameric protein)

• two heavy (H) chains

• Two light (L) chainS

• Two antigen binding sites (variable regions)

• One constant region (same in most antibodies)

Antibody Classes - IgG

The most abundant antibody class in circulation with the longest half-life (approximately one month); confers passive immunity and is capable of crossing the placenta.

Antibody Classes - IgM

The first immunoglobulin class produced by plasma cells during a primary immune response; first responder

Antibody Classes - IgA

The class of immunoglobulins primarily located in mucosal secretions such as mucus, tears, and saliva.

Antibody Classes - IgD

An antibody class that functions primarily as an antigen receptor anchored to the surface of B-cells to assist in their activation.

Antibody Classes - IgE

The least prevalent circulating antibody class; mediates allergic responses and increases markedly in concentration during parasitic worm infections.

Antigen-Antibody Complex

• Abs bind to specific parts of Ag) (affinity) —> binding to their antigen

• MANY reactions may result, such as…

  • Complement fixation (cascade activation)

  • Agglutination

  • Opsonization

  • Ag neutralization

• Primary vs secondary (anamnestic) response

Complement Fixation

An immune reaction triggered when antibodies bind an antigen, initiating a domino-like cascade of complement proteins to destroy the target; start the complement cascade

Agglutination

The cross-linking and clumping of particulate antigens caused by antibody binding; widely utilized in blood typing procedures.

Opsonization

The process by which antibodies or complement fragments coat a pathogen, facilitating its recognition and engulfment by phagocytic cells.

Antigen Neutralization

The binding of antibodies to microbial surfaces or soluble toxins, preventing them from attaching to, entering, or damaging host cells.

Primary Response

First exposure to it

Secondary (Anamnestic) Response

Once already exposed, memory B cells will remember them and have a faster response; response from memory T and B cells

Anamnestic Response

Also called the secondary immune response; a faster, more robust antibody and cellular response upon re-exposure to an antigen driven by memory B and T-cells.

Immunodeficiency

Under response of immune system for some reason

Primary Immunodeficiency

Less common; typically born with; genetic

Secondary Immunodeficiency

Develop a weakened immune system later in life because of an outside factor or condition; An acquired under-responsiveness of the immune system resulting from extrinsic factors such as HIV infection (which depletes helper T-cells), chemotherapy, or nutritional deficiencies (e.g., scurvy).

Hypersensitivity

Over reaction to immune system

Allergy

Reacting to something that they think its a threat

autoimmunity

Body is attacking itself

Alloimmunity

An immune hypersensitivity reaction directed against foreign tissues or cells obtained from another genetically non-identical individual of the same species (e.g., allograft rejection).

Autograft

Tissue transplanted from one anatomical site to another within the very same individual (such as a saphenous vein used for CABG or fat in a BBL).

Isograft

A tissue graft transplanted between genetically identical individuals, such as identical twins.

Xenograft

A tissue graft transplanted between organisms of entirely different species, such as animal connective tissue transplanted into a human.

Immunization

Priming the immune system; active immunity

Immunotherapy

Something that helps the immune system work better; treatment that changes immune system to work better

Attenuated Vaccines

Vaccines composed of whole, living pathogens that have been systematically weakened so they provoke immunity without causing full-blown disease.

Whole Cell Vaccines

Using whole life pathogens; most likely weakened (attenuated) —> give it everything it wants until it becomes weakened; oldest, most traditional type

Acellular / Subunit Vaccines

Vaccines that do not use whole live intact pathogens, instead utilizing isolated antigenic fragments such as specific proteins, peptides, or polysaccharides (e.g., the flu shot).

Toxoid Vaccines

resembles toxoid that prime the host's immune defenses specifically against toxic microbial products (e.g., the tetanus shot).

Recombinant Vaccines

Cutting and pasting DNA/RNA ex: Hep B

mRNA Vaccines

Building messenger RNA to instruct body cells to produce a specific antigen, made very quickly, codes the antigen

Vector Vaccines

Vaccines using a harmless, modified viral vehicle (such as an adenoviral vector) to deliver genetic instructions for a target pathogen antigen into host cells.

Adjuvant

• vaccines may require these by adding something to a vaccine, makes it more effective

Herd Immunity

the more people in a population that are protected, the better the unprotected are

Staphylococcal Skin Diseases (Bacterial)

• usually endogenous bacteria —> already in your body

• Follicilitis

• Furuncles/carbuncles

• Impetigo

• Staphylococcal scalded skin syndrome (SSSS)

• Acne vulgaris and cystic acne

• Often treated with antibiotics and or “lancing” —> cut open, get pus out

  • Watch out for MRSA

Folliculitis

Bacterial inflammation of a hair follicle, frequently caused by Staphylococcus aureus and commonly occurring following shaving.

Furuncles and Carbuncles

Deep, painful, pus-filled cutaneous boils caused by Staphylococcus aureus; a carbuncle is an aggregated cluster or grouping of multiple furuncles.

Impetigo

A superficial, contagious bacterial skin infection most prevalent in young children, presenting with crusting skin sores characterized by a honey-colored appearance.

Staphylococcal Scalded Skin Syndrome (SSSS)

A severe exfoliative toxinosis seen primarily in neonates, wherein circulating toxins produced by Staphylococcus aureus induce widespread epidermal blistering and peeling.

Acne vulgaris

Clogged pores + oil + inflammation; cutibacterium acne

Cystic acne

Inflammed, deep, painful, can cause scars

Methicillin-Resistant Staphylococcus aureus (MRSA)

Strains of Staphylococcus aureus expressing resistance to methicillin and related beta-lactam antibiotics, armed with distinct virulence factors.

Cutibacterium acnes

Bacterial organism involved in the pathogenesis of acne vulgaris and cystic acne by colonizing sebum-rich, clogged pores to produce deep, scarring inflammation.

Pseudomonas infections (Bacterial)

• usually caused by pseudomonas aeruginosa - common soil bacteria

  • Characteristic green and “fruity” odor

• Commonly infects burned skin (80% of deaths in burn patients!)

• May also cause “hot tub rash”, UTI, etc

• VERY difficult to treat (even with antibiotics)

  • High degree of intrinsic resistance! —> evolve by natural resistance a bacterium already has

Intrinsic Resistance

The innate, naturally evolved resistance mechanisms inherent to a bacterial species that render it refractory to antibiotics without acquiring foreign resistance genes.

Gas Gangrene (bacterial) - stinky

• usually caused by clostridium perfringens (C diff)

• Usually transmitted from the environment

• Take advantage of O2-deprived tissues to grow

• Produce toxins that further starve tissues of O2

• Crepitant tissues - turn black and “crackle” (from gas production - VERY foul odor!)

• Treat with antibiotics and hyperbaric therapy

Crepitant Tissue

Devitalized, blackening tissue that produces a distinct crackling sensation and sound upon palpation due to gas accumulation during Clostridium perfringens gangrene.

Hyperbaric Oxygen Therapy

High pressure, high infused oxygen to slow progression of growth

Necrotizing Fasciitis

• aka “Flesh - eating bacteria”

• Usually caused by certain strains of streptococcus progenies

  • Often acts as an opportunistic pathogen —>

  • Many cases now caused by vibrio vulnificus (ocean)

• Bacteria infect fascia(surround skeletal muscles) and “eat” into surrounding tissue - VERY rapid spread

• Bacteria make MANY toxins (e.g. tissue destroying toxins, superantigens (forcefully overstimulate immune system and tissues), etc)

• Treat with heavy doses of IV antibiotics (if caught in time) —> Penicillin, Vanco