Phage Display and Phagemid Vectors Quiz

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Questions and Answers

What is the primary function of the proteins located on the exterior of a phage?

To replicate the viral DNA

To protect the viral DNA from degradation

To synthesize new viral proteins

To recognize and bind to the host cell (correct)

What are phagemid vectors?

Engineered systems containing sites for molecular biology operations. (correct)

Proteins that help in the replication of viral DNA.

A mixture of phage proteins and host cell DNA.

Specific sequences of DNA that control protein expression.

What genetic elements are introduced into phagemid vectors for protein expression?

Sequences coding for other proteins, along with secretion signals and transcription promoters (correct)

Only signal sequences for secretion

Sequences that only encode viral structural proteins

Only promoter sequences

In phage display, where is the protein of interest displayed?

Fused to the proteins of the phage exterior (D) Signup and view all the answers

What is the outcome of inserting foreign DNA into a phagemid vector?

The phage expresses a modified coat protein. (B) Signup and view all the answers

Proteins 3 and 8 are mentioned as specific proteins that can be modified, what type of proteins are they?

Phage coat proteins. (A) Signup and view all the answers

What does the term 'in-fusion' mean in the context of phagemid vectors?

The physical linkage of an inserted peptide and a phage protein. (C) Signup and view all the answers

What is the primary purpose of phage display?

To couple a genotype with its corresponding phenotype on the surface of a phage. (A) Signup and view all the answers

After inserting DNA and expressing the phage, what is the final result regarding the displayed peptides?

Phages displaying peptides corresponding to the inserted DNA (B) Signup and view all the answers

Which components of B lymphocytes are used to generate the diversity in a phage display library?

Variable domains of light and heavy chains (D) Signup and view all the answers

What is the main advantage of using single-chain Fv (scFv) fragments in phage display?

They offer a format for displaying just the Fv without the constant region. (D) Signup and view all the answers

What type of vector is typically used in phage display to express the antibody fragments?

A phagemid vector (C) Signup and view all the answers

How do phages display the antibody fragments on their surface?

By attaching the fragments to the outside of the phage capsid. (B) Signup and view all the answers

What is the purpose of performing PCR of VH and VL regions from B cells in phage display?

To amplify the genes encoding antigen-binding regions of antibodies. (D) Signup and view all the answers

Which of these is NOT a typical source for the B cells from which the antibody fragments are derived?

Cell cultures from cancer patients (C) Signup and view all the answers

What role does error-prone PCR using Taq polymerase play in generating antibody diversity?

It creates mutations in the antibody fragments during PCR (D) Signup and view all the answers

What is the primary function of the Fc domain in the development of immunoconjugates?

To bind with radioactive labels, cytotoxic drugs, or proteins. (B) Signup and view all the answers

What is a key characteristic of bispecific antibodies?

They bind to two different targets with the same molecule. (C) Signup and view all the answers

What is the main principle behind the development of the first approved bispecific antibody?

To crosslink tumor cells with immune cells which normally would not interact. (C) Signup and view all the answers

What is the role of BiTE constructs in cancer therapy?

To act as an adaptor molecule, bringing T-lymphocytes close to tumor cells. (A) Signup and view all the answers

How do bispecific antibodies facilitate the elimination of malignant cells using T lymphocytes?

By promoting the physical interaction between T lymphocytes and malignant cells, thereby activating the T lymphocytes. (C) Signup and view all the answers

What is a key focus in optimizing Fab or Fv domains?

To create bispecific or multispecific antibodies. (D) Signup and view all the answers

What is the implication of extending the half-life of antibodies with a human Fc domain?

It enhances the time the antibody remains effective in the body. (D) Signup and view all the answers

Which company is actively investigating the clinical effectiveness of BiTE antibody based immune therapeutics?

Amgen (A) Signup and view all the answers

What is the primary function of CTLA4 in lymphocyte activation?

To inhibit lymphocyte activation by competing with CD28 for binding to CD80/CD86. (A) Signup and view all the answers

How do anti-CTLA4 antibodies contribute to anti-tumor immunity?

By blocking CTLA4, which results in increased activation of lymphocytes. (C) Signup and view all the answers

What is the mechanism of action of BiTE molecules?

They activate lymphocytes indirectly by binding to tumor cells and immune cells. (D) Signup and view all the answers

The therapeutic activity of BiTE molecules is characterized as?

Indirect, by engaging the lymphocytes' activity against the tumor. (C) Signup and view all the answers

An IgG2 antibody is mentioned in the context of interfering with signal transduction, what does it act on?

It blocks the activation of osteoclasts. (B) Signup and view all the answers

What is the role of CD28 in lymphocyte activation?

It promotes lymphocyte activation through binding to CD80/CD86. (C) Signup and view all the answers

The anti-anthrax protein mentioned in the text is developed using a particular technology. Which one is it?

Phage Display (C) Signup and view all the answers

What is the described similarity between anti-CTLA4 antibodies and BiTE molecules?

They both function indirectly by acting on the lymphocytes. (B) Signup and view all the answers

In adults, Enbrel is used alongside methotrexate when individuals show what type of response to other treatments?

An inadequate response (D) Signup and view all the answers

For which of the following conditions is Enbrel NOT indicated for use in adolescents aged 12 to 17 years?

Ankylosing spondylitis (C) Signup and view all the answers

In adults, for which specific disease of the spine is Enbrel indicated?

Severe ankylosing spondylitis (B) Signup and view all the answers

What is the primary disease characteristic for which Enbrel is used in adults with plaque psoriasis?

Moderate to severe disease (D) Signup and view all the answers

If an adult patient cannot receive methotrexate, how might Enbrel be administered?

As a standalone treatment (A) Signup and view all the answers

What is the origin of the Etanercept protein used in Enbrel?

Human tumour necrosis factor receptor p75 Fc fusion protein produced by recombinant DNA technology (B) Signup and view all the answers

In the context of using Enbrel for severe non-radiographic axial spondyloarthritis, what specific finding must be present to warrant its use?

Objective signs of inflammation (A) Signup and view all the answers

What is the key characteristic of the disease for which Enbrel is used in children with plaque psoriasis?

Long-term severe illness (B) Signup and view all the answers

What is the primary effect of an antibody in the context of T cell activation described in the text?

Inhibition of T cell activation through increased negative signaling. (A) Signup and view all the answers

What is the main design characteristic of Aflibercept (VEGF trap) that improves its pharmaceutical properties over earlier versions?

Deletion of the high pI domain 1 and replacement of high pI domain 3 with a lower pI and better binding domain. (B) Signup and view all the answers

What is the function of Placental Growth Factor (PLGF) that is targeted by Aflibercept?

It is implicated in tumor angiogenesis. (C) Signup and view all the answers

In the context of peptibody technology, what is the purpose of fusing peptides to the Fc domain?

To extend the peptide's serum half-life. (C) Signup and view all the answers

What distinguishes peptibody therapeutics from traditional antibody and receptor-Fc fusion proteins?

Peptibodies utilise peptides to mimic other molecules and to stimulate effects, whereas traditional options are largely antagonists. (D) Signup and view all the answers

What is the therapeutic function of Romiplostim (Nplate)?

Treatment of chronic immune thrombocytopenia purpura. (B) Signup and view all the answers

How does Romiplostim achieve its therapeutic effect?

By binding to and stimulating the same receptors as thrombopoietin. (A) Signup and view all the answers

Which domain of the VEGF receptor was found to have non-specific interactions?

Domain 1. (D) Signup and view all the answers

Study Notes

Natalizumab (TYSABRI)

Treatment for adults with multiple sclerosis (MS)
Used when other MS treatments are not sufficient or if symptoms are rapidly worsening.
Used in relapsing-remitting MS.
Requires a real need due to safety risks.
Fab' fragment, produced in E. coli, then conjugated to polyethylene glycol (PEG) to extend plasma half-life.
Final molecular weight is ~90 kDa.

Cimzia (Certolizumab Pegol)

Treatment for moderate to severe rheumatoid arthritis.
Used in combination with methotrexate, if disease not adequately responding to other treatments.
Used alone, if methotrexate is not appropriate.
Also useful in severe, progressive rheumatoid arthritis cases that have not been previously treated with methotrexate.
Treatment for axial spondyloarthritis, including ankylosing spondylitis, or axial spondyloarthritis without X-ray evidence, with objective inflammation.
Useful in psoriatic arthritis, in conjunction with methotrexate when not well controlled by other DMARDs, and alone if methotrexate is not appropriate.
Does not contain fragment crystallisable (Fc) region so does not fix complement or cause antibody-dependent cell-mediated cytotoxicity in vitro.

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Description

Test your knowledge on phage display and phagemid vectors. This quiz covers the functions of proteins on phages, the design and use of phagemid vectors, and the mechanism of protein expression. Dive deep into the techniques and advantages of using phage display in molecular biology.