BISC 3115 Immune System Fundamentals

Neutrophils

innate; circulate in blood, rapid phagycytosis killing of bacteria; first responders

Monocytes

innate; circulate in blood and differentiate into macrophages or dendritic cells; macrophage precursors

Macrophages

innate; phagocytosis, cytokine secretion, antigen presentation

Mast cells

innate, stationed in tissue, release histamine and inflammation mediators; sentinels

Dendritic cells

innate; stationed in tissue, capture antigens and present them to activate naive T cells

Natural Killer cells

innate; kill virus-infected and cancerous cells without antigen specificity

CD4+ T cells

adaptive; coordinate immune responses through cytokine secretion

TH1 cells

adaptive; activate macrophages and CD8+ T cells through IFN-gamma and IL-2

TH2 cells

adaptive, activate B cells and promote antibody responses through IL-4 and IL-5

CD8+ T cells

adaptive; differentiate into CTL and memory T cells

Cytotoxic T cells

adaptive; kill infected host cells using perforins and granzymes

B cells

adaptive; differentiate into plasma cells and memory B cells

Plasma cells

adaptive; secrete large quantities of antibodies

Memory cells

adaptive; long living and respond rapidly upon re-exposure to antigen

Lysozyme

innate, breaks down bacterial cell walls

Lactoferrin

innate, binds iron, limits bacterial cell growth

Peroxidase

innate, generates hydrogen peroxide

Mannose-binding lectin

innate, activates compliment when bound to microbes

c3a

innate, promotes inflammation

c3b

opsonization, forms c5 convertase, alternative pathway

c5a

innate, powerful chemotatcic factor for neutrophils, alos acts as anaphylatoxin

c5b

innate, initiates MAC formation

MAC

innate, creates pores that lyse cells

TNF-alpha

innate, promotes inflammation and fever

Histamine

innate, vasodilation

Prostaglandins

innate, pain, fever, inflammation

Leukotrienes

innate, vasodilation

IFN-alpha

innate, antiviral cytokine

IFN-beta

innate, antiviral cytokine

IFN-gamma

adaptive, activates macrophages

IL-2

adaptive, stimulates T-cell proliferation

IL-4

adaptive, B-cell activation

IL-5

adaptive, B-cell activation

perforins

adaptive, form pores in target cells, made by CD8 and NK cells

granzymes

adaptive, enter cells and induce apoptosis

IgM

adaptive, first antibody produced during infection

IgG

adaptive, most abundant antibody in blood, secondary response

IgA

adaptive, mucosal immunity

IgD

adaptive, B-cell receptor on naive B cells

IgE

adaptive, allergies and parasite defense

C3b receptor: expressed on, binds to, function?

expressed on phagocytes, binds to C3B, binds opsonized microbes and enhances phagocytosis

Fc receptor: expressed on, binds to, function?

expressed on phagocytes, NK cells, binds to Fc region of antibodies, binds antibodies attached to pathogens

toll-like receptors: expressed on, binds to, function?

expressed on innate immune cells, bind to microbial molecules (PAMPS), recognize pathogen associated molecular patterns

TCR: expressed on, binds to, function?

expressed on T cells, bind to antigenic peptide-MHC complexes, recognize antigen peptides

BCR: expressed on, binds to, function?

expressed on B cells, bind to antigen, recognized native antigen

CD4: expressed on, binds to, function?

expressed on helper T cells, binds to MHC II, coreceptor for MHC II recognition

CD8: expressed on, binds to, function?

expressed on cytotoxic T cells, bind to MHC I, coreceptor for MHC I recognition

CD28: expressed on, binds to, function?

expressed on T cells, bind to B7, costimulator receptor required for activation

B7: expressed on, binds to, function?

expressed on APCs, bind to CD28, provides costimulation to T cells

MHC I: expressed on, binds to, function?

expressed on all nucleated cells, binds to CD8 T cells, presents intracellular antigens

MHC II

expressed on professional APCs, binds to CD4 T cells, presents extracellular antigens