Type I and Type II Interferons

Cytokines and Chemokines

• Cytokines are pleiotropic, acting on various cells and producing different effects.
• Cytokines can be classified into three types: endocrine, paracrine, and autocrine.

T Cell Activation

• Intercellular adhesion molecules (ICAM) are associated with antigen (LFA-1).
• CD40 and CD40L play a crucial role in T cell activation.
• CD28 and B7.1 (B7.2) are involved in T cell activation.

Primary Structures of MHC Class I and Class II

• MHC class I molecules consist of one heavy chain (45 kD) and a light chain called β2-microglobulin (12 kD).
• MHC class II molecules consist of two chains (alpha and β) of similar size (34 and 30 kD).

Interleukins

• IL-2 is involved in T cell growth.
• IL-4 is involved in B cell growth and differentiation.
• IL-5 is involved in B cell differentiation and activates macrophages.
• IL-12 is involved in B cell growth and activates T cells.
• IL-18 is involved in inducing IFN-γ and is a member of the IL-1 family.

Regulation of Normal Body Functions

• Cytokines play a crucial role in regulating various body functions, including metabolism, wound healing, inflammation, infections, and cardiovascular disease.

Schematic Representation of Wound Healing

• Wound healing involves platelet aggregation, cell immigration, removal of debris, cytokine secretion, and neovascularization.

MHC Class I and Class II Pathways

• MHC class I pathway involves the processing of antigens through the endoplasmic reticulum.
• MHC class II pathway involves the processing of antigens through the endosome.

Immune Mediators and Neuroinflammatory Disorders

• Immune mediators contribute to the development of neuroinflammatory disorders, such as multiple sclerosis.
• Cytokines, such as IFN-γ, play a crucial role in these disorders.

Interferons

• Interferons are divided into two types: Type I and Type II.
• Type I interferons (IFN-α and IFN-β) are involved in the first line of antiviral defense.
• Type II interferon (IFN-γ) is involved in the activation of macrophages and the induction of MHC antigens.

Type III Interferons

• Type III interferons (IL-28A, IL-28B, and IL-29) are involved in the antiviral response and the activation of immune cells.

Chemokines

• Chemokines are chemoattractant cytokines that form a large family of structurally related proteins.
• The chemokine superfamily is divided into four groups: CXC, CC, C, and CX3C.
• Chemokines are involved in the regulation of leukocyte migration and accumulation in inflammatory sites.