Infection Science & Immunology – Tutorial 5 (Exam Preparation)

Vocabulary flashcards covering immunology concepts, infection types, immune mechanisms, exam strategies, and key lecture themes to prepare for the Infection Science essay-style exam.

Pathogen

Any microorganism (virus, bacterium, fungus, parasite) capable of causing disease and eliciting an immune response.

Bone Marrow

Primary lymphoid organ where all blood cells, including leukocytes, originate from hematopoietic stem cells.

Thymus

Primary lymphoid organ where T lymphocytes mature and undergo selection.

Spleen

Secondary lymphoid organ that filters blood, removes old erythrocytes, and mounts immune responses to blood-borne antigens.

Lymph Node

Secondary lymphoid organ that filters lymph and is a major site for antigen presentation and lymphocyte activation.

Innate Immune System

Rapid, non-specific first line of defence that relies on barriers, phagocytes, complement, and pattern-recognition receptors.

Adaptive Immune System

Slower, highly specific immune response mediated by B and T lymphocytes with memory formation.

Leukocyte

General term for all white blood cells involved in immunity, including lymphocytes, monocytes, and granulocytes.

Myeloid Lineage

Hematopoietic branch giving rise to granulocytes, monocytes/macrophages, dendritic cells, platelets, and erythrocytes.

Lymphoid Lineage

Hematopoietic branch producing B cells, T cells, and Natural Killer cells.

Granulocyte

Leukocytes containing cytoplasmic granules; includes neutrophils, eosinophils, and basophils.

Monocyte

Circulating precursor that differentiates into macrophages or dendritic cells once in tissues.

Lymphocyte

Adaptive immune cells—B cells, T cells, and NK cells—that recognize specific antigens or abnormal cells.

Neutrophil

Most abundant granulocyte; fast phagocyte that uses oxidative and non-oxidative killing mechanisms.

Eosinophil

Granulocyte specialized in combating parasitic infections and mediating allergic responses.

Basophil

Granulocyte that releases histamine and other mediators during allergic reactions and parasitic defence.

B Cell

Lymphocyte that expresses B-cell receptors, differentiates into plasma cells, and secretes antibodies.

T Cell

Lymphocyte that expresses T-cell receptors and mediates cellular immunity (helper or cytotoxic functions).

Natural Killer (NK) Cell

Innate lymphoid cell that kills virus-infected or transformed cells without prior sensitisation.

Antigen-Presenting Cell (APC)

Cell (e.g., dendritic cell, macrophage) that processes antigens and presents peptides on MHC molecules to T cells.

Phagocytosis

Engulfment and internalisation of particles or microbes by cells such as macrophages and neutrophils.

Complement System

Cascade of plasma proteins that opsonise pathogens, recruit cells, and form membrane-attack complexes.

Inflammation

Local tissue response characterised by heat, redness, swelling, pain, and loss of function aimed at eliminating insult.

Pattern Recognition Receptor (PRR)

Receptor (e.g., TLR, NLR) that recognises conserved microbial motifs (PAMPs) and triggers innate immunity.

Toll-Like Receptor (TLR)

Family of PRRs on immune cells that detect PAMPs and activate signalling pathways for cytokine release.

Pathogen-Associated Molecular Pattern (PAMP)

Conserved microbial structure (e.g., LPS, dsRNA) recognised by PRRs to initiate innate responses.

Respiratory Burst

Rapid production of reactive oxygen species by phagocytes during microbial killing.

B-Cell Receptor (BCR)

Surface immunoglobulin on B cells that binds specific antigen and initiates B-cell activation.

Antibody (Immunoglobulin)

Secreted form of BCR that neutralises pathogens, opsonises targets, and activates complement.

T-Cell Receptor (TCR)

Heterodimeric receptor on T cells that recognises peptide-MHC complexes.

V(D)J Recombination

Somatic gene rearrangement creating diverse BCR and TCR antigen-binding sites.

Junctional Diversity

Additional nucleotide additions or deletions at V(D)J junctions, further increasing receptor variability.

Somatic Hypermutation

Point mutations in immunoglobulin variable regions of activated B cells leading to affinity maturation.

Class Switching

Process by which B cells change antibody isotype (e.g., IgM to IgG) without altering antigen specificity.

CD4

Co-receptor on helper T cells that binds MHC class II and assists in TCR signalling.

CD8

Co-receptor on cytotoxic T cells that binds MHC class I and enhances TCR signalling.

Helper T Cell (Th)

CD4⁺ T cell that secretes cytokines to coordinate and regulate immune responses.

Cytotoxic T Cell (Tc)

CD8⁺ T cell that kills virus-infected or malignant cells via perforin-granzyme pathways.

Extracellular Bacteria

Bacterial pathogens residing outside host cells and mainly targeted by antibody-mediated responses.

Intracellular Bacteria

Bacteria that replicate inside host cells, requiring cell-mediated immunity for clearance.

Viral Immune Evasion

Strategies by viruses (e.g., antigenic variation, MHC down-regulation) to escape host immunity.

Parasite Immune Response

Combined innate and adaptive mechanisms (eosinophils, IgE, Th2 responses) targeting parasitic infections.

Fungal Immune Response

Host defence involving neutrophils, macrophages, complement, and Th1/Th17-mediated immunity.

Immunisation

Induction of protective immunity by vaccination with antigenic material.

Vaccine Types

Includes live-attenuated, inactivated, subunit, toxoid, conjugate, and mRNA vaccines, each with pros and cons.

Diagnostic Methods

Laboratory techniques (e.g., PCR, ELISA, culture) used to detect infectious agents or immune responses.

Schistosoma mansoni

Parasitic trematode causing intestinal schistosomiasis; life cycle involves freshwater snails and skin penetration by cercariae.

Praziquantel

Antiparasitic drug of choice for treating schistosomiasis by causing worm paralysis and tegument disruption.

Innate Defence Against Parasites

Early responses involving complement, eosinophils, macrophages, and mast-cell mediated inflammation.

Humoral Immunity

Aspect of adaptive immunity mediated by antibodies produced by B cells.

Cellular Immunity

Adaptive responses mediated by T lymphocytes and their cytokines.

Antimicrobial

Chemical agent (antibiotic, antifungal, antiviral) that kills or inhibits microorganisms.

Antimicrobial Resistance

Ability of microorganisms to withstand drugs through mechanisms such as efflux pumps or altered targets.

Epidemiology

Study of the distribution, determinants, and control of diseases in populations.

Infection Control

Policies and procedures (e.g., hand hygiene, isolation) to prevent transmission of infectious agents.

Pathogenesis

Biological mechanisms by which pathogens cause disease in the host.

Decode the Question

Exam strategy of analysing command words and content focus to ensure the answer addresses all parts.

Plan–Compose–Revise

Three-step framework for structuring essay answers: outline, write, then edit for clarity and completeness.

Scientific Writing Style

Formal, precise, third-person, past-tense prose using correct terminology and referencing evidence.