Immunology Lec 7 Flashcards
Lecture 7:
What is central tolerance and where does it occur?
Central tolerance occurs in primary lymphoid organs (thymus and bone marrow), where self-reactive T and B cells are deleted or rendered anergic.
What is peripheral tolerance and where does it occur?
Peripheral tolerance occurs outside primary lymphoid organs and involves mechanisms like anergy, deletion, and regulatory T cell (T-reg) induction.
Describe the process of central tolerance in the thymus.
In the thymus, T cells undergo positive selection (interaction with MHC) and negative selection (elimination of self-reactive T cells).
How are self-reactive B cells handled in the bone marrow?
In the bone marrow, B cells encountering self-antigens become anergic.
What are the mechanisms of peripheral tolerance?
Mechanisms of peripheral tolerance include anergy (self-reactive T and B cells become inactive without co-stimulatory signals), deletion (apoptosis of self-reactive cells), and regulatory T cells (T-reg) suppression of immune responses to self-antigens.
What role do CD4+CD25+ T-reg cells play in immune tolerance?
CD4+CD25+ T-reg cells prevent other T cells from attacking self-antigens, maintaining tolerance.
What is FOXP3 and its significance in autoimmunity?
FOXP3 is a transcription factor crucial for T-reg function. Its deficiency leads to autoimmunity.
Name an autoimmune disorder associated with hyperthyroidism.
Graves’ Disease is an autoimmune disorder associated with hyperthyroidism caused by autoantibodies to TSH receptors.
What causes Hashimoto’s Thyroiditis?
Hashimoto’s Thyroiditis is caused by antibodies and T cells attacking thyroid tissues, leading to hypothyroidism.
Which cells are targeted in Type 1 Diabetes Mellitus?
In Type 1 Diabetes Mellitus, T cells attack insulin-producing cells in the pancreas.
What is the immunological target in Multiple Sclerosis?
In Multiple Sclerosis, T cells target CNS neurons leading to demyelination.
What causes inflammation and joint damage in Rheumatoid Arthritis?
In Rheumatoid Arthritis, autoantibodies against joint antigens cause inflammation and joint damage.
What autoantibodies are involved in Systemic Lupus Erythematosus (SLE)?
Autoantibodies against DNA and other nuclear components are involved in Systemic Lupus Erythematosus (SLE), leading to systemic inflammation.
How do genetics influence autoimmunity?
Genetics influence autoimmunity, with HLA associations with diseases (e.g., HLA-B27 with ankylosing spondylitis).
Why are females generally more susceptible to autoimmune disorders?
Females are generally more susceptible due to hormonal influences.
