Immunity Flashcards

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1
Q

Immunity

A

The ability of the host to fight against a disease/infection causing organism (pathogen) encountered by the immune system is termed as immunity

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2
Q

Name the two types of immunity

A
  1. Inborn / Innate / Gerneralised Immunity
  2. Acquired Immunity
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3
Q

Difference b/w vaccine and toxoid

A

Vaccine:
1. Provides lifetime immunity
2. Vaccines contain killed or attenuated disease-causing organisms

Toxoid:
1. 6 months immunity
2. Toxin is produced by the microorganism

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4
Q

Artificially acquired active and passive immunity

A

Active:
Antigens are introduced in vaccines; body produces antibodies and specialised lymphocytes

Passive:
Preformed antibodies in immune serum are introduced by injection

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5
Q

Blood cell formation
1. Early foetal development
2. Mid foetal development
3. Later foetal development

A
  1. mesenchyme of yolk sac
  2. liver and spleen
  3. bone marrow
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6
Q

Bone marrow function

A
  1. Gives rise to all lymphoid cells
  2. Maturation and proliferation of B-cells (B-Lymphocytes)
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7
Q

Thymus function

A
  1. Major action of thymus occurs during childhood
  2. Maturation and differentiation of T-cells (T-Lymphocytes)
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8
Q

Lymph nodes function

A
  1. Non-specific filtration of particulate matter
  2. Proliferation of B and T lymphocytes
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9
Q

Spleen function

A
  1. B-cells and T-cells multiply
  2. Removal of debris, particulate matter and aged/defective RBC- MALT, NALT, GALT, BALT

MALT: Mucosal Associated Lymphoid Tissue
NALT: Nasal
GALT: Gut
BALT: Bronchiole

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10
Q

Phagocytosis

A

Phagocytosis is a non-specific response. It is the process of engulfment and destruction of particles such as bacteria, allergens etc. by specific cells like macrophages and neutrophils

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11
Q

Inflammation

A

Inflammation is a protective and non-specific immune response which is elicited due to a tissue injury. Inflammation can be localised or systemic.

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12
Q

Inflammation- steps

A
  1. Tissue injury
  2. Swelling: Vasodilation of the capillaries around the area of tissue damage
  3. Redness: Increased amount of blood flow in the area
  4. Heat: Temperature raises locally in that specific region
  5. Pain: Permeability of the capillaries result in the escape of plasma into the surrounding region
  6. Plasma contains phagocytic cells, antibodies, and bactericidal agent
  7. Destruction of antigens and healing of tissue
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13
Q

Difference b/w B-cells and T-cells

A

B cells
1. maturation and differentiation in bone marrow
2. accounts for humoral immune response

T cells
1. maturation and differentiation in thymus
2. accounts for cell-mediated immune response

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14
Q

APCs

A

Antigen Presenting Cells
Macrophages and neutrophils
Destroy antigens by phagocytosis, non-specific immune response

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15
Q

Interferons

A
  1. Anti-viral in action
  2. Specific in nature
  3. Signaling proteins released by virus infected cells
  4. Interfere with viral replication
  5. Signal the neighbouring cells to increase their anti-viral defenses

Examples:
IFN-alpha and IFN-beta are secreted by virus infected cells
IFN-gamma is secreted by T-cells, NK cells and Macrophages

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16
Q

Antigens

A
  1. Foreign molecule that can trigger the immune system of the host organism in producing an antibody
  2. Most anitgens are either proteins or polysaccharides
  3. Lipids and nucleic acids become antigenic only when they combine with a protein or polysaccharide
17
Q

Haptens

A

These are small molecules that can elicit an immune response only when attahed to a large, carrier molecule, like a protein

18
Q

Antibodies

A
  1. Proteins (Gamma globulins)
  2. Specific in function
  3. Released by Plasma cells (B-cell)
  4. Forms Ag-Ab complex to facilitate the destruction of antigen
19
Q

Effector mechanisms

A
  1. Agglutination
  2. Opsonisation
  3. Complement (specialised plasma proteins) mediated cell lysis
20
Q

Number of binding sites in IgG, IgM, IgA, IgD, IgE

A

IgG, IgD, IgE: monomers–> 2 binding sites
IgM: pentamer–> 10 binding sites
IgA: dimer–> 4 binding sites

21
Q

Percentage of total antibody in serum
IgG, IgM, IgA, IgD, IgE

A

IgG: 80%
IgM: 6%
IgA: 13% (monomer)
IgD: <1%
IgE: <1%

22
Q

Fc receptor binds where in IgG and IgE

A

IgG- phagocytes
IgE- mast cells and basophils

23
Q

Function of IgG

A
  1. Neutralization
  2. Agglutination
  3. Complement activation
  4. Opsonization
  5. Antibody-dependent cell-mediated cytotoxicity
24
Q

Function of IgM

A
  1. Neutralization
  2. Agglutination
  3. Complement activation
  4. The monomer form serves as the B-receptor
25
Q

Function of IgA

A

Secretory antibody
1. Neutralization
2. Trapping of pathogens in mucus
3. Present in tears, saliva, and colostrum

26
Q

Function of IgD

A

B-cell receptor
Active against parasitic infections

27
Q

Function of IgE

A

Activation of basophils and mast cells against parasites and allergens

28
Q

Allergy

A

An oversensitive reaction by the immune system against a foreign particle (Allergen)

29
Q

Clinical manifestations of an allergy

A
  1. Itching
  2. Swelling
  3. Redness
  4. Typical wheal and flare reaction on the skin
30
Q

Treatment for allergic reaction

A

Administering anti-histamine drugs

31
Q

Autoimmunity

A
  1. The condition where an individual produces antibodies against one’s own antigens
  2. The body loses its ability to differentiate between self and non-self antigens
32
Q

Disease when there is autoimmune disorder related to
1. RBC antigen
2. Muscle antigen
3. Thyroid antigen
4. Antigens in joins

A
  1. Chronic anaemia
  2. Myasthenia gravis
  3. Hashimotto’s disease
  4. Rheumatoid arthritis
33
Q

Immunodeficiency disorders

A
  1. SCID- Severe Combined Immuno-deficiency- T and B cells absent: congenital
  2. Di George’s Syndrome- lack of T-cells
  3. Agammaglobulinemia- lack of B-cells
  4. AIDS: Acquired Immunodeficiency Syndrome