Immunology Exam 2

refers to the overall strength of binding between an antibody and its antigens, taking into account all of the binding interactions.

• Avidity

• Affinity

Answer explanation

Avidity refers to the overall strength of binding between an antibody and its antigens, taking into account all of the binding interactions. IgM, with its pentameric structure, has ten binding sites, allowing it to bind more antigens and form more stable complexes compared to IgG, which has only two binding sites. This makes IgM’s avidity higher than that of IgG

is the initial force of attraction that exists between a single Fab site on an antibody molecule and a single epitope or determinant site on the corresponding antigen.

• Avidity

• Affinity

Answer explanation

Affinity

Affinity is the initial force of attraction that exists between a single Fab site on an antibody molecule and a single epitope or determinant site on the corresponding antigen. As the epitope and binding site come into close proximity to each other, they are held together by weak bonds occurring over a short distance of approximately 1 × 10–7 mm.

The strength of attraction depends on the specificity of antibody for a particular antigen. One antibody molecule may initially attract numerous different antigens, but it is the epitope’s shape and the way it fits together with the binding sites on an antibody molecule that determine whether the bonding will be stable. Antibodies are also capable of reacting with antigens resembling the original antigen that induced antibody production, a phenomenon known as cross-reactivity. The more the cross-reacting antigen resembles the original antigen, the stronger the bond will be between the antigen and the binding site. However, if the epitope and the binding site have a perfect lock-and-key fit, as is the case with the original antigen, the affinity will be maximal. When the affinity is higher, the assay reaction is more sensitive because more antigen-antibody complexes will be formed and visualized more easily

If glacial acetic acid needs to be diluted with water to make a 10% solution, what does the glacial acetic acid represent? Type your answer in lowercase form

Tags

NGSS.HS-PS1-5

True or False: Prozone phenomenon a false-negative reaction may occur as a result of high antibody concentration

• True

• False

Which technique involves measurement of the turbidity or cloudiness of a solution?

• Nephelometry

• Immunoturbidimetry

• ELISA

• Flow Cytometry

Which technique measures the light scattered at a particular angle from the incident beam as it passes through a suspension?

• Nephelometry

• Immunoturbidimetry

• ELISA

• Flow Cytometry

Tags

NGSS.HS-PS4-3

NGSS.HS-PS4-5

Which technique measures the preciptin ring diameter to indicate the concentration of the antigen?

• Nephelometry

• Immunoturbidimetry

• RID

• IFE

• Ouchterlony double diffusion

This technique is used when both antigen and antibody diffuse out from wells in a gel, and patterns of precipitate lines form to indicate the relationship of antibodies.

• Nephelometry

• Immunoturbidimetry

• RID

• IFE

• Ouchterlony double diffusion

This technique involves electrophoresis of serum followed by direct application of reagent antisera to the gel

• Nephelometry

• Immunoturbidimetry

• RID

• IFE

• Ouchterlony double diffusion

True or False: In competitive immunoassays the more patient antigen present, the less labeled antigen is detected.

• True

• False