25.Acquired immunity. Types. Structure of antibodies. Polyclonal and monoclonal antibodies. Antigen-antibody reaction.

Question 1

Acquired Immunity

Answer 1

• develops after your body has been introduced to a pathogen
  -is divided into humoral and cellular
• B- lymphocytes are responsible for humoral immunity –> develop in the bone marrow
• T- lymphocytes are responsible for cellular immunity –> develop ine the thymus

Question 2

Mechanisms of acquired immunity

Answer 2

T and B Lymphocytes only recognize one type of mole, high specifity - known as immonocompetent cells

Question 3

Structure of antibodies (immunoglobulins)

Answer 3

• protein with a quaternary structure
• 4 polypeptide chain, 2 heavy + 2 light chains
• Symmetrical, Y-shaped, 2 antigen binding site

Exeptions:
- some antibodies might be pentamer (5 units) / dimer (2 units)

Types of immunoglobulins and main characteristics
- IgG – a major effector of the immune response. The only one that crosses placenta.
- IgM – phylogenetically oldest. It is synthesized first after antigen exposure and is the main Ig in primary immune response.
- IgA - occurs at end of immune response. It protects the mucous
membrane of various organs from viruses, bacteria, etc. microorganisms.
- IgE – in a very low quantities. Increases in allergic reactions.
- IgD – membrane-bound receptor for B-cells. It is expressed in mature B-lymphocytes under the action of the antigen (immature ones express only IgM).

Question 4

Polyclonal and Monoclonal antibodies

Answer 4

1. Monoclonal: 1 type, are identical antibodies that are all the same
   - come from 1 type of immune cells
   - very specific and precis
2. Polyclonal antibodies
   Many types. Mix of dif antibodies
   - come from fid immune cells
   - they are not as specific

Application of monoclonal antobodies
- used in home-pregnancy kizs
- detection of microbial pathogens
- used to treat patient with cancer -> Monoclonal antibodies mark cancer cells. Bring T cells close to cancer cells.
- uses to deliver poison to cancer cells

Reaction mediated by LgE antibodies
- antibodies found on surface of mast cells and basophils
- results in a cascade of events resulting in an allergic reaction
-involves release of histamines

Clinical Symptoms
- skin symptoms - redness, swelling, or itching
- respiratory symptoms - sneezing, runnz nose (rhinorrhea), coughing
- gastro intestical symptoms - nausea, vomitting, diarrhea, and abdominals cramping

Question 5

Antigen- antibody reaction

Answer 5

• paratope (binding site on antibody) reacts with epitope (small part to the antigen molecule
• key + lock method
• not a chemical reaction
• high affinity for epitope is called specific
• low affinity is called cross- reaction