Exam 3 - Autoimmune diseases and immunodeficiencies

Autoimmune diseases

-Immune attacks against self antigens

-Damages normal organs/tissues

Immunologic tolerance

-T cell or antibodies that react to self are normally not activated and destroyed

-Central and peripheral tolerance

Central tolerance

-Self-reactive lymphocytes are destroyed

-Occurs in thymus and bone marrow

Peripheral tolerance

Anergy and apoptosis of self-reactive lymphocytes

Anergy

-Lack of a costimulatory protein

-Lymphocyte does not respond

What are two causes of autoimmunity?

1. Microbial infections

2. Environmental factors (UV radiation, smoking, etc)

What are two ways that microbial infections can cause autoimmunity?

1. Self reactive

2. Mimicry

Self-reactive microbial infection

Microbe causes activation of self-reactive T cell

Mimicry microbial infections

Microbial antigen activates self-reactive lymphocytes by mimicking self antigens

Systemic lupus erythematosus

-Antibodies directed against nuclear antigens

-Causes polyarthritis, renal disease, and skin lesions

Myasthenia gravis

Receptor against ACh (muscle) receptor

Inflammatory myopathies

-Autoantibodies against muscle fibers

-Inflammatory disease in skin, muscles, and vasculature

-Affects younger dogs

Immunodeficiency diseases

Inability to mount an immune response from a genetic or acquired defect

What are three categories of immunodeficiency diseases?

-Disorders of barrier systems

-Disorders of innate immune response

-Disorders of the adaptive immune response

Epitheliogenesis imperfecta category, cause and signs

-Barrier

-Genetic from alterations in ECM cells

-Causes loss of epithelium or mucosae

Chemical and physical barriers category, cause, and signs

-Barrier

-Cold weather suppresses respiratory cilia (aquired)

-Causes fungal infections in newborn birds

Ciliary dyskenia category, cause, and signs

-Innate

-Genetic defects of proteins in dynein (arms) of cilia

-Causes non-motile cilia, bronchitis, and pneumonia

Leukocyte adhesion deficiency category, cause, and signs

-Innate

-Genetic disorder that causes a decrease in adhesion molecules (integrins)

-Causes neutrophils to be unable to enter bloodstream and destroy bacterial infection

Cyclic hematopoiesis (gray collie syndrome) category, cause, and signs

-Innate

-Genetic disorder causing a neutrophil stem cell defect

-Cyclical flu-like symptoms every 11 days

Severe combined immunodeficiency (SCID) category, cause, and signs

-Adaptive

-Can be genetic or acquired

-Defect in leukocyte development

-Causes reoccurring illnesses and flu-like symptoms

Agammaglobulinemia

Defect in B cell development

Thymic hyperplasia

Defect in T cell development

Feline immunodeficiency virus (FIV) category, cause, and signs

-Adaptive

-Acquired (through bites)

-Depletion of lymphocytes (CD4+) causes thymic atrophy

-Causes flu-like symptoms, wasting, or hematologic depression

Feline leukemia virus (FeLV)

-Adaptive

-Acquired (through saliva)

-If antibody present: virus eradicated

-If no antibody present: Lymphoma