Immunology and Infection Lecture: Use of Antibodies in Diagnostics and Research – ELISAs

These flashcards cover key concepts regarding immunology, antibodies, diagnostics, and ELISAs based on the lecture notes.

What holds the heavy (H) and light (L) chains of an antibody together?

Interchain disulphide bonds and reversible bonding.

What is the purpose of the hinge region in antibodies?

It provides flexibility between the two Fab arms.

What are immunoglobulins?

Glycoproteins that possess carbohydrate groups which enhance solubility and modulate biological functions.

What are the two types of light chains in antibodies?

Kappa (κ) and Lambda (λ) chains.

How many distinct classes of antibody (isotypes) are there?

Five distinct classes based on the constant region of the heavy chain.

What are the classes of antibodies?

IgA, IgD, IgE, IgG, and IgM.

What are hypervariable regions in antibodies?

Regions that show the greatest amount of variability in the variable regions of both light and heavy chains.

What are complementarity determining regions (CDRs)?

The hypervariable regions that participate in binding to an antigen.

What is the difference between polyclonal and monoclonal antibodies?

Polyclonal antibodies are a mixture from different B cells recognizing different epitopes; monoclonal antibodies are identical antibodies produced from a single B cell.

Which cells are fused to create hybridomas for monoclonal antibody production?

Normal activated B cells are fused with myeloma cells (cancerous plasma cells).

What is Trastuzumab?

An immunobased therapy for breast cancer targeting the HER2 protein.

What is the role of sodium dodecyl sulfate (SDS) in SDS-PAGE?

It denatures protein antigens in the mixture.

What does ELISA stand for?

Enzyme-Linked Immunosorbent Assay.

What is the basis of ELISA?

It uses antibodies covalently bound to enzymes to detect the presence of antibodies or antigens.

What is measured in an indirect ELISA?

Antibodies.

What is the key step in a Sandwich ELISA?

Adding the antigen to be measured after coating the well with antibodies.

What is the purpose of a Competitive ELISA?

To measure antigen levels in a pre-incubation solution.

What is the significance of the negative control in ELISA?

To ensure specificity and reliability of the assay's results.

What does the antigen-binding region of an antibody consist of?

The Fab region, which includes both the light and heavy chains.

What does 'scaffold' refer to in the context of antibodies?

Framework regions providing structure to the immunoglobulin fold.

What enhances the biological functions of immunoglobulins?

Carbohydrate groups attached to them.

What are the five heavy chain isotypes?

Gamma (γ), mu (μ), alpha (α), epsilon (ε), and delta (δ).

How are CDRs related to antibody specificity?

CDRs directly participate in binding to a specific antigen, allowing for specificity.

What defines the specificity of monoclonal antibodies?

They recognize a single epitope on an antigen.

What is the significance of the standard curve in an ELISA?

It is used to determine the concentration of a protein in a sample.

Describe the steps of an indirect ELISA.

1. Coat well with antigen. 2. Add specific antibody. 3. Add enzyme-conjugated secondary antibody. 4. Add substrate and measure color change.

Why are polyclonal antibodies useful?

They can recognize multiple epitopes and form larger antigen-antibody complexes.

What is the role of the variable regions in antibodies?

To provide diversity and specific binding capabilities to different antigens.

In what situation would you prefer monoclonal antibodies over polyclonal antibodies?

When a specific antigen recognition is required, such as in clinical diagnostics.

What does the term 'isotype' refer to regarding antibodies?

Different classes of antibody based on the constant region of the heavy chain.

How can you measure color change in an ELISA?

By adding a substrate that reacts with the enzyme linked to the antibodies.