Intro to Vaccination Flashcards
Which of the following mechanisms contribute to the diversification of antibody-binding?
-Somatic hypermutation
-Junctional diversification during gene segment joining
-Isotype switching
-Independent combinatorial joining of heavy and light chain
-Combinatorial joining of gene segments
-Somatic hypermutation
-Junctional diversification during gene segment joining
-Independent combinatorial joining of heavy and light chain
-Combinatorial joining of gene segments
During B cell development, the V and J gene segments (for the light chain) and the V, D, and J gene segments (for the heavy chain) are joined together at random to form a functional antibody binding site (CDR). This random, combinatorial joining of gene segments leads to a great diversity of the antibody specificity.
During the joining of these segments, some nucleotides are often lost from the ends of the recombining gene segments. At the same time also one or more randomly chosen nucleotides can be inserted. This random loss and gain of nucleotides at joining sites is called junctional diversification, and it enormously increases the diversity of V-region coding sequences created by recombination.
Since the recombination of the antibody binding site (CDR) or the light chain and the heavy chain occur independent from each other, but both CDRs contribute to the specificity of the antibody, and to the fact that the probability that both the light as well as the heavy chain are recombined exactly the very same way, it is almost entirely impossible that two antibodies are created that have the very same sequence and thus the very same specificity.
After rearrangement antibodies normally undergo several rounds of affinity maturation. During this process, mutations occur at the rate of about one per V-region coding sequence per cell division. This is about a million times greater than the spontaneous mutation rate. This process is called somatic hypermutation. and substantially contributes to the diversity of antibodies.
Isotype switching affects the constant region of the heavy chain and does not affect the specificity of what an antibody recognizes, but changes the specificity of which FcR can recognize the antibody.
Which of the following techniques is dependent on monoclonal antibodies?
–Radioallergosorbent test (RAST)
–Immunohistochemistry
–Fluorescence-activated cell sorting (FACS)
–Enzyme-linked immunosorbent assay (ELISA)
–None of the above. All these techniques can be performed using polyclonal anti-serum
None of the above
All of them could be performed using polyclonal anti-serum; nevertheless, all of them are much facilitated if monoclonal antibodies can be used.
Which ONE of the following statements regarding B cell hybridoma is false?
A) They are immortal cell lines that produce antibodies of a single specificity.
B) They have to be derived from B cells that are first cloned and grown in cell culture for short periods.
C) They contain more chromosomes since they are formed by the fusion of two cells.
D) They can be used to manufacture diagnostic or therapeutic monoclonal antibodies.
E) They are derived by fusing B cells with malignant plasma cells that are unable to secrete antibodies.
They have to be derived from B cells that are first cloned and grown in cell culture for short periods.
B cell hybridoma re created by the fusion of a B-cell with a malignant plasma/myeoloma cell, which by itself does not secrete any antibodies. This leads to a duplication of chromosomes of an immortal cell line that produces antibodies of a single specificity. However, B-cells can be fused with myeloma directly ex vivo and do not have to be grown in cell culture first.
A monoclonal antibody specific for a single epitope of an antigen is used both to coat the wells of the ELISA plate and as the enzyme-labelled detecting antibody in a conventional sandwich ELISA. The ELISA failed to detect the antigen despite the use of a wide range of antibody concentrations. What is the most probable cause of this problem?
–The antigen is too large.
–The antibody has a low affinity for the antigen.
–The monoclonal antibody used to sensitize the wells is blocking access of the epitope, thus when the same antibody is enzyme-labeled, it cannot bind to the antigen.
–The enzyme-labeled antibody used should have been a different isotype than the sensitizing antibody.
–The monoclonal antibody used is probably unstable.
The monoclonal antibody used to sensitize the wells is blocking access of the epitope, thus when the same antibody is enzyme-labeled, it cannot bind to the antigen
In a sandwich ELISA, an antibody (often monoclonal) is used to coat ELISA wells followed by blocking with a nonspecific protein to saturate any unbound sites. The antigen is then added, followed by the addition of a second antigen-specific antibody that is enzyme- labeled. Either a polyclonal, antigen-specific antibody or another monoclonal antibody, which recognizes another epitope as the coating antibody, is used as the enzyme-labeled reagent. This is done, because the original epitope detected by the coating antibody will be blocked. If the same monoclonal is used as the enzyme-labeled detecting antibody as well as the coating antibody, then the enzyme-labeled detecting antibody will not be able to detect the epitope / antigen any longer.
What are some features of the adaptive immune response underlying vaccination?
What are the different types of vaccines and route of administration?
Give named examples of vaccinations using the different types of vaccines
What are the different adjuvants and their function?
What are some of the challenges of developing and licensing vaccines?
