Biology of Disease

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Cytokine Rolesin vivo TH1 or TH2 cytokine

IL-2 stimulates growth of T lymphocytes;

increases activity of NK cells

TH 1

IL-3 stimulates hemopoiesis TH1 and TH 2

IL-4 promotes growth and differentiation of

B lymphocytes;

promotes growth of TH2 cells;

growth factor for mast cells

TH 2

IL-5 promotes growth and differentiation of

B lymphocytes and eosinophils

TH 2

IL-6 promotes acute phase response; stimulates

differentiation of B lymphocytes

TH 2

IL-9 activates mast cells TH 2

IL-10 inhibits production of TH1 cells TH 2

IL-13 growth and differentiation of B lymphocytes TH 2

IL-14 B cell growth factor

InterferonF activates macrophages and NK cells;

inhibits TH2 cells

TH 1

TNF-A promotes acute phase response; cytotoxin TH 1

Granulocyte-Monocyte

Colony Stimulating

Factor (GM-CSF)

stimulates hemopoiesis TH1 and TH 2

Table 4.5A range of THcytokines

TCR

MHC class II

Antigen presenting cell

TH (CD4+)

Memb

rane

Memb

rane

Superantigen

Figure 4.26 A schematic showing the linking

of an MHC Class II molecule to a TCR by a

superantigen as described in text.

Superantigens such as Toxic Shock

Syndrome Toxin cause massive

stimulation of TH cells by linking the

T cell receptor to the MHC Class II

protein outside the peptide binding

groove (Figure 4.26). Since this does

not depend on the TCR being specific

to the antigen, many more T cells are

stimulated than usual. The high level

of cytokine release leads to shock

with severe clinical consequences

(Chapter 3).

Margin Note 4.6 Superantigens

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