Comprehensive Immunology and HIV/AIDS Pathophysiology for Advanced Study

What is the primary function of the immune system?

To defend against foreign substances, including bacteria, viruses, fungi, and abnormal cells.

What are the two main types of immunity?

Innate immunity and adaptive (or acquired) immunity.

What is the difference between passive and active immunity?

Passive immunity is acquired through antibodies from another source, while active immunity is developed through exposure to an antigen.

What are the first lines of defense in the immune system?

Physical barriers such as skin and mucous membranes.

What role does the acidity in the stomach play in the immune system?

It helps activate pepsinogen and destroys bacterial microorganisms entering the mouth.

What are the components of the innate immune response?

Includes barriers like skin, mucosa, and cells such as neutrophils, natural killer cells, and macrophages.

What is the role of neutrophils in the immune system?

They are the most abundant granulocytes and act as early responders in innate immunity.

What is the function of macrophages?

They phagocytize foreign substances and cellular debris, and initiate the adaptive immune response.

What distinguishes adaptive immunity from innate immunity?

Adaptive immunity is specific to particular pathogens and has memory, while innate immunity is non-specific and immediate.

What are T cells and their functions?

T cells are lymphocytes involved in adaptive immunity; they include cytotoxic T cells that kill infected cells and helper T cells that activate other immune cells.

What are B cells responsible for in the immune system?

B cells produce antibodies that target specific antigens.

What is the inflammatory response?

A nonspecific reaction to injury characterized by redness, heat, swelling, pain, and loss of function.

What triggers the inflammatory response?

Injury, infection, tissue necrosis, or foreign bodies.

What are the signs and symptoms of inflammation?

Redness, heat, swelling, pain, and loss of function.

What are the roles of mast cells in inflammation?

They release histamines and other mediators that initiate the inflammatory response.

What is the significance of phagocytosis in the immune response?

Phagocytosis is the process by which phagocytes engulf and destroy pathogens and debris.

What are inflammatory mediators?

Substances released during inflammation, such as histamines, cytokines, and prostaglandins, that promote vasodilation and increased vascular permeability.

What is the role of natural killer (NK) cells?

NK cells directly attack infected or cancerous cells and help regulate the immune response.

What is the difference between specific and non-specific immune responses?

Specific responses target particular pathogens, while non-specific responses act against all foreign substances.

How does the body recognize foreign antigens?

Through the action of lymphocytes, which identify and respond to specific antigens.

What is the role of cytokines in the immune system?

Cytokines are signaling proteins that mediate and regulate immunity, inflammation, and hematopoiesis.

What is the function of lysozymes in mucus?

Lysozymes are enzymes that destroy bacterial cell walls, providing a defense mechanism in the respiratory tract.

What is the purpose of vaccination?

Vaccination stimulates the adaptive immune response by exposing the body to a harmless form of an antigen.

What is the role of the skin in the immune system?

The skin acts as a physical barrier to prevent the entry of pathogens.

What are granulocytes?

A type of white blood cell that contains granules in their cytoplasm, including neutrophils, eosinophils, and basophils.

What is the significance of memory cells in the immune system?

Memory cells provide long-lasting immunity by remembering past infections and responding more rapidly upon re-exposure.

What is the initial vascular response to injury?

Brief vasoconstriction of small vessels.

What follows vasoconstriction in the vascular response?

Rapid dilation of local arterioles and venules, leading to redness and warmth.

What causes increased capillary permeability during inflammation?

It leads to edema, pain, and impaired tissue function.

What are the signs of inflammation due to the vascular response?

Redness, swelling, heat, pain, and loss of function.

What is the role of leukocytes in the cellular response to injury?

Movement of leukocytes, mainly neutrophils, to the site of injury, attracted by cytokines.

What are the three steps of leukocyte movement during inflammation?

Adhesion and margination, transmigration, and chemotaxis.

What is the process called when leukocytes exit blood vessels?

Diapedesis.

What triggers vasodilation in the inflammatory response?

Release of histamine from mast cells.

What is the function of histamine in inflammation?

It increases the dilation and permeability of blood vessels, allowing fluids to collect around an injury.

What is the pharmacologic treatment for inflammation?

Aspirin (ASA), NSAIDs, and corticosteroids.

What are the two types of lymphocytes involved in adaptive immunity?

T-Lymphocytes (T-cells) and B-Lymphocytes (B-cells).

What type of immunity do T-Lymphocytes provide?

Cell-mediated immunity.

What type of immunity do B-Lymphocytes provide?

Humoral immunity.

What is the difference between active and passive immunity?

Active immunity involves producing antibodies, while passive immunity involves receiving antibodies from another source.

What is clonal selection in B lymphocytes?

The process where B-cells that bind to an invader's antigen rapidly reproduce and differentiate into plasma or memory cells.

What do plasma cells do?

They rapidly produce antibodies.

What is the role of antibodies in the immune response?

They bind to specific antigens, disable microbes, or agglutinate them for recognition by white blood cells.

What are the two subtypes of T-Lymphocytes?

Helper T-Cells (CD4) and Cytotoxic T-Cells (CD8).

What is the function of Helper T-Cells?

They activate other immune cells by releasing cytokines.

What do Cytotoxic T-Cells do?

They seek out and destroy infected cells.

What is the Major Histocompatibility Complex (MHC)?

A cluster of proteins on the surface of nearly all nucleated cells that helps the immune system distinguish self from non-self.

What is Type I Hypersensitivity?

An IgE-mediated immediate allergic reaction, which can include systemic or local reactions.

What occurs during the early phase of Type I Hypersensitivity?

Mast cell degranulation and release of histamine, causing vasodilation and bronchoconstriction.

What happens during the late phase of Type I Hypersensitivity?

Lipid mediators are released, leading to bronchospasms and prolonged inflammation.

What is the role of cytokines in the immune response?

They activate various immune cells, including macrophages, cytotoxic T-cells, and B-cells.

What are prostaglandins and leukotrienes involved in during anaphylaxis?

They are released systemically and contribute to symptoms such as marked hypotension, bronchospasm, edema, angioedema, and itching.

What is anaphylaxis?

A life-threatening Type I hypersensitivity reaction affecting the cardiovascular and respiratory systems, often involving IgE.

What are the signs of Grade I anaphylaxis?

Cutaneous and mucosal tissue reactions, including erythema and urticaria, with or without angioedema.

What symptoms characterize Grade II anaphylaxis?

Hypotension, tachycardia, dyspnea, and gastrointestinal disturbances like nausea and vomiting.

What are the symptoms of Grade III anaphylaxis?

Bronchospasms, cardiac dysrhythmias, and potential cardiac collapse.

What occurs in Grade IV anaphylaxis?

Cardiac arrest.

What is Type II hypersensitivity?

An antibody-mediated reaction involving IgG or IgM, seen in conditions like blood transfusion reactions and Graves' disease.

What causes the symptoms in Graves' disease?

Antibodies against acetylcholine receptors lead to hyperthyroidism and muscle weakness.

What is Type III hypersensitivity?

An immune complex-mediated reaction characterized by the accumulation and deposition of antigen-antibody complexes in tissues.

What are examples of conditions associated with Type III hypersensitivity?

Systemic lupus erythematosus (SLE), acute glomerulonephritis, serum sickness, and rheumatoid arthritis.

What are the common autoantibodies produced in systemic lupus erythematosus (SLE)?

Antibodies against DNA, RNA, erythrocytes, coagulation proteins, phospholipids, and lymphocytes.

What are the clinical manifestations of SLE?

Arthralgias, vasculitis, renal disease, hematologic changes, and cardiovascular disease.

What are the eleven common findings for diagnosing SLE?

Facial rash, discoid rash, photosensitivity, oral ulcers, non-erosive arthritis, serositis, renal disorder, neurologic disorder, hematologic disorders, immunologic disorders, and presence of antinuclear antibodies (ANA).

What is Type IV hypersensitivity?

A delayed hypersensitivity reaction mediated by T-lymphocytes, causing cell death and tissue injury.

What are examples of Type IV hypersensitivity reactions?

Contact dermatitis, latex allergy, and poison ivy reactions.

What is the structure of the HIV virus?

An enveloped virus covered by a lipid bilayer with glycoprotein spikes (gp120 and gp41) for attachment to CD4 cells.

What is the primary method of HIV transmission?

Contact with blood and body fluids, with sexual contact being the most common route.

What phases characterize HIV infection?

Primary infection, chronic asymptomatic (latency), and overt AIDS.

What are the symptoms of primary HIV infection?

Flu-like symptoms including fever, fatigue, rash, headache, lymphadenopathy, and oral/genital ulcers.

What defines overt AIDS?

A CD4 cell count below 200 cells/µL or the development of certain opportunistic infections.

What is an opportunistic infection?

An infection that occurs when the immune system is compromised, allowing microorganisms to cause disease.

What is the most common opportunistic infection in AIDS?

Pneumocystis jiroveci pneumonia.

What is the leading cause of death for people with AIDS?

Mycobacterium tuberculosis.

What is the treatment for AIDS?

Antiretroviral therapy (ARV) to improve immune status and reduce mortality and morbidity.

What are the goals of treatment for systemic lupus erythematosus (SLE)?

To control symptoms and prevent further organ damage.

What role does UVA light play in SLE?

It may initiate flares, hence patients are advised to protect themselves from sun exposure.