Lecture 9

Question 1

Antibody mediated effector functions:

Answer 1

1. Accumulate in the plasma, mucosal secretions and tissue interstitial fluid
2. Neutralization of microbes or microbial toxins
3. Activation of the complement system (classical pathway)
4. Opsonization of pathogens for enhanced phagocytosis
5. Antibody dependent cell mediated cytotoxicity
6. Antibody mediated mast cell activation

Question 2

Multivalent antigen

Answer 2

multiple different epitopes in macromolecule

Question 3

Polyvalent:

Answer 3

multiple identical epitopes in macromolecule

Question 4

Immunogen:

NOT ALL ANTIGENS ARE IMMUNOGENS

Answer 4

Immunogen: substance that activates lymphocytes and stimulates an immune response

Question 5

T-independent antigen

Answer 5

Polysaccharide antigens cross link multiple B cell antigen receptors, generating an activation signal strong enough to activate the B cell independent of T cell help (called a T-independent antigen).

Question 6

T-dependent antigen

slide 16

Answer 6

Protein antigens allow the B cell to elicit help from activated CD4 T cells (T-dependent antigen)

Question 7

Haptens and carriers

Answer 7

Hpteans- bind to the B cell

Carrier- linear peptide code that is within a Hapten (microbial protein antigen)

Question 8

Small chemicals such as dinitrophenol (DNP) or many common drugs (such as penicillin) may bind to antibodies, and are therefore antigens, but they cannot activate B cells on their own.

Answer 8

DNP, may bind to antibodies but cannot activate B cells on their own (i.e., it is not immunogenic). But…..

Haptens may become immunogenic when they combine with a protein carrier, which allows the B cell to elicit CD4 T cell help.

We refer to DNP as a HAPTEN, which cannot activate an immune response on its own. In order to do so, the hapten must become fused to a protein (called a CARRIER) to create an immunogen.

Question 9

Drugs such as penicillin behave as haptens

Answer 9

Drugs such as penicillin behave as haptens and react with the surface proteins of RBCs, thereby creating new antigens on the cell surface.

This stimulates the formation of Abs that are specific for the conjugate of the drug (hapten) and cell surface protein (carrier).

Binding of antibodies to penicillin-modified RBCs may induce complement mediated lysis or target them for phagocytosis by macs in the spleen.

The result is immune mediated hemolytic anemia.

Question 10

Hapten-Carrier Complexes

Answer 10

slide 21

Question 11

Adjuvants

Answer 11

hep induce a robust immune response

Some adjuvants induce inflammation, therefore, inducing expression of costimulatory molecules.

Substances that by themselves are not immunogenic, but can enhance the immunogenicity of other substances.

Adjuvants induce Ag aggregation, making it more likely to be phagocytosed, processed and presented to T cells

Question 12

ALUM…….

Answer 12

The main class of adjuvants licensed for use in the United States are the aluminum salt adjuvants (aluminum hydroxide, aluminum phosphate, and aluminum potassium sulfate), commonly referred to as ALUM.

Question 13

Vaccines that contain Alum:

Answer 13

DTP (diphtheria-tetanus-pertussis vaccine)
DTaP (diphtheria-tetanus-acellular pertussis vaccine)
Some but not all Hib (Haemophilus influenzae type b) conjugate vaccines
Pneumococcal conjugate vaccine
Hepatitis B vaccines
All combination DTaP, Tdap, Hib, or Hepatitis B vaccines
Hepatitis A vaccines
Human Papillomavirus vaccine
Anthrax vaccine
Rabies vaccine

Question 14

toxoid

Answer 14

slightly altered toxin that is not toxic anymore but it does create an inflam response and help to immunize

ex) tetanus

Question 15

cross reactiviity

Answer 15

A specific antibody or T cell receptor can recognize two very similar, yet non-identical antigens

Question 16

Clinical Correlation: Rheumatic Fever

Answer 16

1. Antibody and activated T cells respond to Streptococcus pyogenes antigens
2. Antigen is similar in structure to self-antigens on the heart valves
3. Fever, rash, carditis, arthritis, sub-q nodules, Syndenham chorea
   JONES criteria

Question 17

A 41 year old patient visits a physician for a physical. She recalls to her physician that in childhood, she experienced two bouts of fever, headache and sore joints following severe sore throats. Although she appears to be well at the present, which of the following sequelae of her childhood illness is most likely to present as a chronic disease in her later years?

Answer 17

Mitral valve disease

Question 18

A patient treated with penicillin presents with fever associated with kidney damage from complement-mediated hemolysis of red blood cells (RBC). What is the role of penicillin in this disorder?

Answer 18

Hapten