[2] Immunoglobulins - Biochemical Basis of Diseases

What are the 3 major components of the immune system?

1. B Lymphocytes → from bone marrow

2. T Lymphocytes → thymic origin

3. Innate immune system → defends against infection (non-specific)

True or False: All immunoglobulins contain a MINIMUM of one light and two heavy chains

False

All immunoglobulins contain a MINIMUM two light and two heavy chains

What is the purpose of variability in antigen binding regions for immunoglobulins?

to bind a tremendous number of structurally diverse antigens

What does the amino terminal variable (V) regions do?

antigen recognition

What does the carboxyl-terminal constant (C) regions do?

the C regions of the heavy chains mediate effector functions​

immunglobulin molecules are divided into 5 classes:​

IgG, IgA, IgM, IgD and IgE​

Acronym: GAMED

What are the subcategories of lgA

IgA1 and IgA2

What are the subcategories of lgG

IgG1,IgG2, IgG3, and IgG4.

which lg class is a pentamer?

LgM

which lg class is a dimer?

what lg class is a monomer?

lgG and lgD

Which lg class is the most abundant? (what percentage in serum)

lgG (75% of the total serum lg)

What does the lgG class do?

→ Neutralizes bacterial toxins and viruses​

→ Is the only class of Ig that crosses the placenta

Which lg class is the second most abundant?

lgA

Where is the lgA class found?

Found in the body secretions:

tears, breast milk, saliva, mucus of the bronchial, genitourinary, and digestive tract​

Which lg class is the third most abundant?

lgM

What does the lgM class do?

1st Ig produced in a primary response to an antigen and serve as first line of defense.

Which lg class is the fourth most abundant?

lgD

What is the function of lgD (trick question)?

its role in serum uncertain​

Where is lgD located?

Found on the surface of B cells where it acts as a receptor for antigen​

Which lg class is the least abundant?

lgE

What is the function of lgE

Defends against worm infections

Cause release of mediators from mast cells and basophils upon exposure to antigen (allergen)

What is the inclusive definition of an immune response?

a reaction to components of microbes as well as to macromolecules, such as proteins and polysaccharides, and small chemicals that are recognized as foreign, regardless of the physiologic or pathologic consequence of such a reaction​.

What is an innate immunity

It consists of cellular and biochemical defense mechanisms that are in place even before infection and are poised to respond rapidly to infections.

they respond similarity for any type of infection or injured cells

What are some components of innate immunity

Physical and chemical barriers →epithelia and antimicrobial chemicals
Phagocytic cells → dendritic cells, and natural killer (NK) cells​
Blood proteins →
Cytokines

What is a con of innate immunity compared to adaptive immunity

Innate Immunity doesn’t distinguish fine differences between microbes​

What is adaptive immunity?

Form of immunity develops as a response to infection and adapts to the infection​

its in the name bruh….

What are the main components of adaptive immunity

lymphocytes → which excrete antibodies

What are antigens?

Foreign substances that induce specific immune responses

or

are recognized by lymphocytes or antibodies

What are the two types of adaptive immune responses?

Humoral immunity

and

Cell-mediated

What is humoral immunity mediated by?

mediated by molecules in the blood and mucosal secretions, called antibodies, which are produced by cells called B lymphocytes (also called B cells)

What is cell-mediated immunity mediated by?

mediated by T lymphocytes (also called T cells).​

What is it called when individuals and lymphocytes have not encountered a particular antigen?

naive (immunological inexperienced)

What is it called when individuals who have responded to a microbial antigen and are protected from subsequent exposures?

immune

What is adoptive transfer in the context of immunity?

transferring serum or lymphocytes from a specifically immunized individual to someone who is not.

What is passive immunity?

The recipient of an adoptive transfer becoming immune to a particular antigen without having been exposed to that antigen

can antibodies from passive immunity be produced by memory cells?

NO - only active immunity

when does active immunity take effect? what about passive?

active: overtime (usually several weeks)

passive: immediately

what is the length of efficacy (perform its desired function) in active immunity? what about passive?

active: longterm to lifelong

passive: short-term

Where does active immunity come from?

1. Direct infection

2. Vaccination

Where does passive immunity come from?

breast milk

injection/blood transfusion

mother to baby through placenta