Understanding Immunological Concepts: Tolerance, Autoimmunity, Tumor Immunity, and Congenital Deficiencies

 

Tolerance and its induction:

- Tolerance is the immune system's ability to recognize and tolerate self-antigens.

- Induced centrally in the thymus (T cells) and bone marrow (B cells) during development.

- Mechanisms include negative selection, receptor editing, anergy, regulatory T cells (Tregs), and immune privilege.

 

Autoimmune diseases and their factors and mechanisms:

- Autoimmune diseases occur when the immune system attacks the body's own tissues.

- Factors include genetic predisposition, environmental triggers, and immune dysregulation.

- Mechanisms include molecular mimicry, breakdown of tolerance, aberrant lymphocyte activation, and inflammation.

- Examples: rheumatoid arthritis, lupus, type 1 diabetes, multiple sclerosis.

 

Tumor immunity and associated antigens:

- Tumors express tumor-specific antigens (TSAs) or tumor-associated antigens (TAAs).

- Immune responses target tumors through CTLs, NK cells, and tumor-infiltrating lymphocytes (TILs).

- Tumors evade immune detection through antigen downregulation and immunosuppressive mechanisms.

 

Congenital B and T cell deficiencies:

- Rare genetic disorders impairing B and/or T lymphocyte development or function.

- Examples: severe combined immunodeficiency (SCID), X-linked agammaglobulinemia (XLA), DiGeorge syndrome.

- SCID: absence of functional T and B cells, severe susceptibility to infections.

- XLA: lack of mature B cells and immunoglobulins, recurrent bacterial infections.

- DiGeorge syndrome: defects in T cell development, chromosome 22 deletion.