Antibodies and monoclonal antibodies
Introduced| English | Meaning |
|---|---|
| antibody/ˈæntɪbɒdi/ | A protein produced by immune cells that binds to a particular antigen and helps the immune system respond to it. |
| antigen-binding site/ˈæntɪdʒen ˈbaɪndɪŋ saɪt/ | The region of an antibody that specifically binds a complementary part of an antigen. |
| variable region/ˈveərɪəbl ˈriːdʒn/ | The part of an antibody whose amino-acid sequence differs among antibodies and helps determine antigen-binding specificity. |
| monoclonal antibody/ˈmɒnəʊklɒnl ˈæntɪbɒdi/ | An antibody from a single cell clone, with molecules sharing the same specificity for an antigenic site. |
| hybridoma/ˌhaɪbrɪˈdəʊmə/ | A cell produced by fusing an antibody-producing B cell with a tumour cell so it can multiply and produce a specific antibody. |
Custom-made weapons
- An antibody 抗体 is a Y-shaped protein made by plasma cells.
- Each one fits one antigen exactly — like a lock and key.
- We can even mass-produce a single type for medicine.
Monoclonal antibodies are:
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Monoclonal = "one clone" — all identical, so they all bind the same target.
Antibody structure and action
- The two tips of the Y are the antigen-binding sites 抗原结合位点.
- Each site has a variable region 可变区 — a special shape that fits one antigen only.
- Antibodies help by: sticking to antigens, clumping pathogens together, marking them for phagocytes, and blocking toxins.
A Y-shaped antibody with two antigen-binding sites
Inside an antibody
Tap each part. The variable tips bind one specific antigen; the constant stem is the same in every antibody.
The variable region of an antibody:
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The two tips of the Y are variable regions — each shaped to bind one specific antigen.
Select all the ways antibodies help destroy pathogens.
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Antibodies agglutinate pathogens, mark them for phagocytes and neutralise toxins — they do not build cell walls.
Match each term to its meaning.
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The variable tip is specific; the constant stem calls phagocytes; agglutination clumps; monoclonal = all identical.
Monoclonal antibodies
- A monoclonal antibody 单克隆抗体 is a single, identical type of antibody, made by the hybridoma 杂交瘤 method:
- an animal is given an antigen, so it makes B-lymphocytes that produce the wanted antibody.
- those B-lymphocytes are fused with tumour cells (which divide endlessly).
- the fused hybridoma both makes the antibody and divides without stopping.
Making monoclonal antibodies with a hybridoma
A hybridoma is made by:
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The B-lymphocyte supplies the wanted antibody; the tumour cell makes it divide endlessly — together a hybridoma.
A B-lymphocyte fused with a tumour cell, so it both makes antibody and divides endlessly, is a ______.
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The hybridoma is cloned to mass-produce one (monoclonal) antibody.
What they're used for
- diagnosis — detecting a specific molecule (e.g. a pregnancy test).
- treatment — carrying drugs to specific target cells, such as cancer cells.
Monoclonal antibodies are used in:
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They detect specific molecules for diagnosis, and can carry drugs to specific target cells for treatment.
You've got it
- an antibody is Y-shaped; the tips are variable regions that bind one antigen
- antibodies clump, mark, and block toxins so pathogens are dealt with
- monoclonal = one identical antibody, made by a hybridoma (B-lymphocyte + tumour cell)
- used in diagnosis (pregnancy test) and treatment (target drugs to cancer cells)
Write from one epitope
- A preparation of antibodies comes from a single clone of B cells.
- Each antibody has the same variable region.
What do these monoclonal antibodies bind?
One clone produces one specificity.
What do monoclonal antibodies bind?
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A single clone has a single specificity.