Immunology 2 Flashcards
What are the main characteristics of the Adaptive system ?
- Antigen specificity
- Diversity
- Immunologic memory (ability to respond to a 2nd encounter of the same antigen more rapidly than the 1st encounter)
- Ability to distinguish b/wn self and non-self recognition
What are the 2 major cell groups of Adaptive Immunity ?
1) B lymphocytes (B cells)
2) T lymphocytes (T cells)
Name 3 types of Antigen-presenting cells (APC’s) ?
What are APC’s described as and what is their role?
- Dendritic cells
- Macrophages
- B lymphocytes
A cross-bridge b/wn Innate and Adaptive immunity. APC’s internalize antigens, break them down (and display part of the antigen bound to MHC II)
MHC II is only expressed by APC’s and interacts with T cells. TRUE or FALSE ?
TRUE
B lymphocytes mature in the red bone marrow. TRUE or FALSE ?
TRUE
B lymphocytes binds to B cell receptors. TRUE or FALSE ?
TRUE
B cell receptors are membrane bound antibodies. TRUE or FALSE ?
TRUE
Name the 2 co-stimulatory molecules that T cells express on their membrane ?
1) T helper (Th) CD4+
2) T cytotoxic (Tc) CD8+
What do T cells recognise ?
Antigens that are bound to MHC
What are the two types of responses in adaptive immunity ?
1) Humoral response (B cells differentiate to Plasma cells which produce Antibodies) …Antibodies go on to bind to antigen etc
2) Cellular response (concerned with T cells)
Describe the structure of a Surface and soluble antibody ?
Both consist of Heavy and light chains joined together by DISULFIDE BONDS w/antigen binding sites on their surface
Does the light or heavy chain determine the class of the antibody ?
Heavy chain
What happens when Th cells are activated ?
Cytokine secretion occurs -which then leads to activation of B, Tc cells and macrophages
Name the 5 major classes of antibodies/Immunoglobulins ?
1) IgA (alpha)
2) IgD (delta)
3) IgE (epsilon)
4) IgG (gamma)
5) IgM (mu)
What is meant by ‘Dimer of dimers’ ?
This is when 2 heavy-light chains of antibodies are joined together
What region of an antibody is the most difference found ?
CD region (complementary determining region)/Antigen binding site
What does the c-region of antibodies result in ?
The 5 different isotopes;
Alpha, Gamma, Epsilon, Mu and Delta
Name 3 regions of an Antibody ?
1) V (variable) region - consists of 110 amino acids
2) C region - involved in the structure of the antibody - determines the effector activity
3) CD region - (complementary determining region)/Antigen binding site
What fragments are produced when Antibodies are digested by the enzyme, Pepsin ?
1) Fab fragments (Antigen binding site)
2) Fc fragments (binds to B cells and only contains H chain)
What is the role of Mercaptoethanol?
Reduces the disulfide bonds therefore producing two fragments
How many sub-classes of IgG are there, name them
4 sub-classes; IgG 1, IgG 2, IgG 3 and IgG 4
Which is the most potent IgG subclass ?
IgG 3
Which IgG subclasses are able to cross the placenta ?
IgG 1, IgG 3 and IgG 4
Where is IgA predominantly found ?
In secretions. e.g: Milk, Saliva, Tears and Mucus
What is the role of IgA ?
To prevent the attachment of bacteria and viruses to the mucous membrane. Also protects from newborns
Name 3 theories for antibody diversity ?
1) Germ-line theory -(Germ cells containing large numbers of Ig genes)
2) Somatic-variation theory (Genome = contains small amount of Ig genes therefore antibody specificity came about by mutation or recombination)
3) One gene -one polypeptide theory (generally accepted)
In L chains, the V region is coded for by which 2 genes ?
V and J (different V an J genes fuse together)
In H chains, the V region is coded for by which 3 genes ?
V, J and D
What are Viruses ?
Small nucleic acids with protein and lipoprotein coating
What is the difference between Protozoans and Helmintic Parasites ?
- Protozoans are unicellular parasites that reside and multiply in host cells.
- Helmintic Parasites = multicellular - eventhough they infect humans are able to survive on their own
What parasite causes Malaria ?
P. Falciparum (P = plasmodium)
What are the 3 classes of reactions involved in Bacterial cell metabolism ?
- Class 1 reactions
- Class 2 reactions
- Class 3 reactions
What occurs in Class 1 reactions ?
Glucose and Phosphate combines with other small molecules and form PRECURSOR MOLECULES and ATP
What occurs in Class 2 reactions ?
Precursor molecules create larger structures e.g: Nucleotides, AA’s and Hexosamines
What occurs in Class 3 reactions ?
Class 2 structures create; Peptidoglycan, Proteins and RNA & DNA
Class 3 reactions are the best target for bacterial chemotherapy. TRUE or FALSE ?
TRUE
What are the 2 types of resistance specific to bacteria ?
1) Acquired - emerge from previously sensitive bacterial populations
2) Intrinsic - Prevents antibiotic action
Name the 3 methods of Horizontal Gene Transfer ?
1) Bacterial transformation (releases DNA to recipient cell)
2) Bacterial transduction (releases Phage)
3) Bacterial conjugation (transfers plasmid from donor to recipient cell at the site they join together)
What is Vancomycin ?
An antibiotic used as a last resort e.g to treat MRSA
