L17 + 18: Regulation of Adaptive Immunity

What can excessive immune response cause?

• Allergies

• Autoimmunity

• Amyloidosis

• Lymphoid Tumors

What happens when there’s too little of an immune response?

• Increased infection

• Increased cancers

When do immature lymphocytes become tolerant to antigens?

Early in fetal life → body is learning what is self-antigen and what’s not

Central Tolerance

Only optimal reactive T cells are released from thymus → eliminates self-rective T cells

• Negative and Positive Selection

Ensures immune system doesn’t attack its own tissues

Peripheral Tolerance

If self-reactive T cells or those with lack of co-stimulation escape central tolerance…

• Treg → supress responses

• Apoptosis

• Anergy → inactivate

AIRE

Autoimmune Regulator

Transcription Factor

Binds to epigenetic marks on histones to recruit transcription factors

Anergy

Lack of co-stimulators on APCs causes T cells to have long-lived functional inactivation

• T cell will not produced IL-2 → won’t proliferate

What is the function of Treg cells?

Treg supresses T cells or APC → blocks activation