Applied Microbiology Week 11 - Innate and Adaptive Immunity

Flashcards covering innate and adaptive immune systems, specific cell roles, key mechanisms like the complement system, and antibody classes based on the microbiology revision transcript.

Innate immunity

The body’s first line of defence and non-specific immune response that responds rapidly to pathogens without needing prior exposure.

Lysozyme

An enzyme found in tears and saliva that impacts microbial growth.

Sebum

A substance produced on the skin that acts as a chemical barrier against microbial growth.

Defensins

Chemical substances produced at different sites that impact upon microbial growth.

Neutrophils

The most abundant white blood cells and first responders to infection that perform phagocytosis and kill bacteria using enzymes and reactive oxygen species.

Basophils

Cells involved in allergic and inflammatory responses that release histamine and heparin.

Eosinophils

Cells important against parasitic infections and contributing to allergic reactions.

Mast cells

Tissue-located cells that release histamine during inflammation and allergies to trigger vasodilation and increased vascular permeability.

Monocytes

Immune cells that circulate in the blood and can differentiate into macrophages.

Macrophages

Tissue phagocytes derived from monocytes that engulf pathogens and dead cells, and present antigens to T cells.

Dendritic cells

Professional antigen-presenting cells (APCs) that link innate and adaptive immunity by activating T cells.

Natural Killer cells

Cells that destroy virus-infected and tumour cells by detecting abnormal cells lacking normal MHC I.

Cytokines

Small signalling proteins like Interleukins, Interferons, and Tumour necrosis factor (TNF) that coordinate immune responses.

Complement

A group of plasma proteins activated in a cascade that functions in opsonisation, cell lysis, and inflammation promotion.

PAMPs

Pathogen Associated Molecular Patterns; molecules commonly found on pathogens such as Lipopolysaccharide (LPS), Peptidoglycan, and Viral RNA.

PRRs

Pattern Recognition Receptors; receptors on immune cells that recognise PAMPs to trigger innate immune responses.

TLR4

A specific Toll-Like Receptor that recognises bacterial Lipopolysaccharide (LPS).

Adaptive immunity

Specific immunity developed after exposure to antigens, characterized by immunological memory and antigen specificity.

Clonal expansion

The process by which activated lymphocytes rapidly multiply during an immune response.

Cell-mediated Immunity

An immune response involving T lymphocytes rather than antibodies to destroy infected cells.

MHC Class I

A complex found on almost all nucleated cells that presents intracellular antigens to CD8+ T cells.

CD8+ T cells

Cytotoxic T cells that recognise antigens on MHC I and release perforin and granzymes to induce apoptosis in target cells.

CD4+ T cells

Helper T cells that bind antigen-MHC II complexes and help activate B cells, macrophages, and CD8+ T cells.

Professional APCs

Antigen-presenting cells that express MHC II, specifically Dendritic cells, Macrophages, and B cells.

Humoral immunity

Immunity mediated by B cells and antibodies present in body fluids, defending against extracellular pathogens and toxins.

Plasma cells

B cell-derived cells that produce and secrete antibodies (immunoglobulins).

IgG

The most abundant immunoglobulin in the secondary immune response that is capable of crossing the placenta.

IgA

An immunoglobulin found in secretions such as saliva, tears, and breast milk.

IgM

The first antibody produced during an immune response, characterized by a pentamer structure.

IgE

An immunoglobulin involved in allergic reactions and defence against parasites.

IgD

An immunoglobulin that functions mainly as a B cell receptor.

Fab fragment

Fragment antigen-binding; the portion of an antibody that binds specifically to an antigen and contains variable regions.

Fc fragment

Fragment crystallisable; the part of an antibody that interacts with immune cell receptors and complement to promote phagocytosis.