Defenses Against Disease Origin of Immune Cells Bone - - PowerPoint PPT Presentation

Defenses ¡Against ¡Disease ¡

Bone marrow stem cell Myeloid precursor Lymphoid precursor Monocyte Granulocytes Dendritic cell Macrophage Neutrophil Mast cell T cell B cell Plasma cell

Thymus maturation Bone marrow maturation

Origin ¡of ¡Immune ¡Cells ¡

Antibody Mediated Immunity

TCR MHC II ¡ Pathogen antigen Cytokines

TH2 cell Antigen- reactive B cell Plasma cell

Antigen presentation Cytokine activation

• f B cell

Uptake and degradation

• f pathogen

B cell forms many plasma cells Production

• f antibody

Primary response Secondary response

Antigen reexposure Antigen exposure Time (d) Immune response 200 100

Complement and Antibodies

Macrophage membrane Antibody FcR C3R Complement Pathogen Antigen

Antitoxin/Exotoxin reaction

Cell Toxin molecules Neutralized toxin Toxin + antitoxin

Cell damage Cell not damaged

Figure 28.13

Time (months) after HIV exposure Normal range for TH cells Significantly depressed TH cells Severe TH cell depletion TH cells per mm3 of blood Symptom- free Swollen lymph glands Subclinical immune dysfunction Oppor- tunistic infections Systemic immune deficiency HIV RNA copies per ml

• f blood

Death 1000 900 800 700 600 500 400 300 200 100 6 12 18 24 30 36 42 48 54 60 66 72 78 84 106 104 102

Hypersensitivity

B cell TH cell Mast cell

Allergies

Hay fever, asthma Antigen IgE Mast cell binding fragment T cell with T cell receptor to antigen IgE receptor APC interacts with B and T cells B cell makes IgE to antigen Helper function IgE sensitizes tissue mast cells by binding to surface IgE receptors Antigen cross- links two antibody molecules Subsequent exposure to antigen Release of allergic mediators (histamines, serotonin, and so on)