Learn: Unit 9 · In vitro antigen–antibody reactions

What are antibodies?

Antigen-specific immunoglobulins used to detect microorganisms or toxins.

What two main approaches does the lecture contrast?

In vitro antigen-antibody reactions and indirect diagnosis.

Which animals are examples of those used for antibody production?

Rats and rabbits.

What are polyclonal antibodies?

Antibodies from multiple B-cell clones recognizing different epitopes on one antigen.

In the rabbit diagram, what activates B cells?

Antigens.

In the rabbit diagram, what cells are formed alongside plasma cells?

Memory B cells.

What do plasma cells secrete in the rabbit diagram?

Antibodies.

What is collected from the animal in the rabbit antibody production diagram?

Antiserum.

What are monoclonal antibodies?

Antibodies that come from a single clone.

In the hybridoma method, what cells are fused together?

Antibody-producing spleen B cells and immortal myeloma cells.

After fusion in the hybridoma method, what is done with the hybrid cells?

They are selected, grown, and individual clones are screened.

Where is the chosen hybridoma grown for production?

In tissue culture.

What are the main disadvantages of the hybridoma method?

It is costly and time-consuming.

What labels are used on antibodies in histology to identify microorganisms?

Gold or fluorochromes.

How does direct staining work in histology?

A labeled primary antibody binds directly to the antigen.

How does indirect staining work in histology?

An unlabeled primary binds the antigen and a labeled secondary binds the primary.

What is precipitation in this context?

Soluble antigens binding specific antibodies at suitable pH and temperature to form an insoluble precipitate.

What is agglutination?

The clumping of antigen-bearing cells or microorganisms by specific antibodies.

How does immunomagnetic separation work?

Antibodies and magnetic particles label selected cells, and a magnet retains them.

What do commercial kits utilize for detection?

Antigen-antibody reactions.

What is indirect diagnosis?

A method that detects specific antibodies produced by the patient, such as by ELISA.

What are two advantages of these reactions mentioned in the lecture?

High sensitivity and specificity.

How can a blood sample be used as an advantage?

To assess localized infections.

How can antibody concentration and isotype be used after infection clears?

To help infer the stage of infection and identify prior exposure.

How do IgM and IgG timing compare during the primary response?

IgM rises earlier than IgG.

How does the secondary immune response compare to the primary response?

It is faster and stronger.

What is a limitation regarding positive results after an infection?

A positive result can persist after the infection has cleared.

Why is it difficult to interpret results involving normal flora?

There is difficulty attributing illness to normal flora due to cross-reactions.

What limitation is caused by low antibody levels in immunocompromised patients?

Infection is harder to detect, and there is a lack of a microbial isolate for an antibiogram.