Hi there, I'm Mrs. Kemp, and welcome to today's lesson all about monoclonal antibodies.

This is from the unit Medicines and New Treatments for Disease.

So let's get started then.

Let's have a look at our outcome, and this is, "I can explain how monoclonal antibodies are produced and describe some ways in which they are used." Today, we're going to be using lots of new key terms, and here they are on the board for you.

But rest assured that I will go over each one of these as we move through the slide deck.

If you would like to stop and pause and have a read of them, please do that now.

We've got three learning cycles for today: antibodies, monoclonal antibodies, and uses of monoclonal antibodies.

So let's start with just a recap of antibodies.

So the human body is made up of cells.

Some pathogens are also made of cells.

For example, bacteria and fungi.

Here, we can see a body cell there on the left and a pathogen on the right.

On their surface, they have those molecules that are known as antigens.

Antigens are made of proteins, and they have a specific shape.

Lymphocytes are a type of white blood cell, and they're able to recognise the antigens on the cell's surface.

It's a bit like a form of identification, and it's because they have that specific shape.

You can see there that the lymphocyte would not recognise its own body cells.

However, it can recognise the pathogen because of the antigen on its surface.

Lymphocytes usually respond to antigens or that are on pathogens.

Sometimes, mistakes can happen, and they can recognise body cells and that's when you lead to sort of autoimmune diseases.

Different pathogens then, like I said, do have different antigens on their surface.

Let's have a look at three examples here.

We can see that each one of those pathogens has got a different shaped antigen.

And lymphocytes will recognise a pathogen by the shape of that antigen, and they will only recognise one type of pathogen.

There's our lymphocyte there, our white blood cell.

So each lymphocyte will only respond to one specific antigen.

So lymphocyte A will respond to pathogen A, but will not respond to pathogen B, because the antigen on its surface is not the correct shape.

Similarly then, lymphocyte B will be able to recognise pathogen A but will not be able to recognise pathogen B.

This means that each lymphocyte will only respond to one specific pathogen.

That's really important, because that's how it becomes important to build up immunities to specific types of pathogens.

So lymphocytes can then produce antibodies which are complimentary, so they fit together.

Be very careful not to say same shape.

They are complimentary.

If they were the same shape, they wouldn't fit together.

Complimentary means that they fit in together.

Each lymphocyte only produces one specific type of antibody, and the antigens and antibodies are typically both proteins.

And we can see there those antibodies are able to fit together with those antigens.

Which of the antibodies would bind to this pathogen, do you think? A, B, or C? I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, did you realise that it's B? Excellent, well done.

Okay, onto our first task of the day then, and you can record your results on your worksheet if you get that out.

So first of all, I'd like you to draw three diagrams. The first diagram is a pathogen with an antigen on its surface.

The second is a lymphocyte producing an antibody.

The third, an antibody binding to an antigen on the surface of a pathogen.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, let's have a look at some drawings that you could have made then.

The first one here is our pathogen with that antigen on its surface.

The next one shows a lymphocyte that has the antibodies being produced, and then we have the antibody fixing onto the antigen of that pathogen.

Just be very careful with the part of the antibody that fits onto the antigen, as sometimes, people can make mistakes with this.

Okay, onto our second learning cycle.

This one is monoclonal antibodies.

So monoclonal antibodies, let's break that word down to start off with.

The 'clonal' part means that an identical copy has been made, and 'mono' means one thing.

So a monoclonal antibody is an identical copy of one thing, that one thing being a single clone of a lymphocyte.

A lymphocyte, remember, is a special type of white blood cell that can produce antibodies.

Scientists has actually discovered a way to produce monoclonal antibodies in a laboratory scenario.

They are used for diagnosis, so finding out if somebody has a disease or a condition, a treatment, and also, laboratory testing.

So let's find out how to do that then.

So in order to make a monoclonal antibody, first of all, you need a living that has an immune system.

They often use mice.

Mice are very small and they're easy to keep, and they grow to adulthood very quickly.

An antigen is first injected into the mouse, and this will cause an immune response to the mouse.

The lymphocytes in the mouse's immune system then produce specific antibodies against the injected antigen.

The scientists then need to find the cells that produce the lymphocyte, and they get these from the spleen of the mouse.

And they do this for a very small operation.

The lymphocytes do not divide easily, and so it's quite difficult to then produce more of them in the lab.

So they have to undergo another process in order to make them replicate easily in a lab.

So what they use are tumour cells.

Tumour cells will divide really rapidly.

And what they do is they fuse together the lymphocyte and the tumour cells.

The myeloma cells, they're called, in order to form a hybridoma cell.

This is a hybrid of the tumour cell and the lymphocyte cell together.

The hybridoma cells then continue to divide, making many identical copies so they will reproduce much more quickly.

The cloned hybridoma cells are grown in culture, so in a broth that contains all of the nutrients that they need, and continue to make the antibody.

These are known as monoclonal antibodies.

Okay, onto our next check then.

Who correctly describes how monoclonal antibodies are made? First of all, we've got Aisha.

"Monoclonal antibodies are made by injecting a person with an antigen from a mouse." Lucas: "Lymphocytes are injected into the mouse's spleen to make monoclonal antibodies." Sofia: "Mouse lymphocytes are fused with tumour cells and cloned to make the antibodies." I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, did you realise that it was Sofia? They take the mouse lymphocytes, and they get those from the spleen, don't they? And they are fused with the tumour cells and clone to make the antibodies.

Excellent.

Really well done.

So because we're using mice, then it is really important to make ethical considerations.

We need to consider whether or not the use of the monoclonal antibodies outweighs the use of the animals in their production.

So it is something that scientists will need to make sure that the benefits outweigh the risks.

Okay, let's go onto another check then.

Can you match the key term to the correct definition? Number one, hybridoma; number two, lymphocyte; number three, monoclonal antibody; number four, myeloma cell.

Can you match those then with (a) produced from a single clone of a lymphocyte, (b) lymphocyte and tumour cell used together, (c) a tumour or type of tumour cell, or (d) white blood cell capable of producing antibodies? I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, did you match hybridoma with (b) lymphocyte and tumour cell fused together? Lymphocyte goes with (d) white blood cell capable of producing antibodies.

Number three, monoclonal antibody with produced from a single clone of a lymphocyte.

Number four, myeloma cell, a type of tumour cell.

Excellent, well done.

Let's use those key terms then in order to remember how we make monoclonal antibodies.

So you can get your worksheet out again in order to record your answers on there.

Describe how mice can be used to make monoclonal antibodies.

Use the following key terms in your answer.

Antigen, lymphocyte cells, tumour cells, hybridoma cells.

You might find the images on the right hand side of the slide useful.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, let's have a look at what we could have included then.

So first of all, a mouse is injected with an antigen.

The mouse is an immune response to the antigen.

Lymphocyte cells are removed from the mouse's spleen and fused with the tumour cells.

The new cells are called hybridoma cells.

These are grown and divide in culture, making many clones of themselves.

The clones make monoclonal antibodies against the antigen.

I hope you've got all those points down, but if you need to add some more to your answer, please do that now.

Okay, onto our final learning cycle of today, uses of monoclonal antibodies.

So monoclonal antibodies can be used in tests to detect specific molecules.

Let's have a look at some examples.

First of all, detecting pathogens to diagnose disease.

What we can do here is we can take a little test strip and we can add a monoclonal antibody to it, so it's actually attached to the test strip.

They then bind to the antigen on a specific pathogen in a sample of saliva or blood.

So we would need to pass across that test strip some saliva, or you would need to pass across some blood.

And if the pathogen is in there, it would stick to that monoclonal antibody.

A positive result would show that the specific pathogen is present.

Often, they have two lines.

And one, the first line will show us that actually, it's working.

The second line will show us whether or not it's positive or negative.

So for this example, if you had two lines that appear on your test strip, that would mean that you were positive for that particular disease.

Okay, second example then this is detecting pregnancy, so this is detecting a condition.

Pregnant women actually produce a short hormone called HCG, and we can find it in their urine.

Monoclonal antibodies have been made so that they are able to bind with that hormone.

Remember, hormones can be made of proteins.

These monoclonal antibodies are attached to a pregnancy stick.

Okay, so just like we saw for the pathogen, we are attaching that monoclonal antibody to the test strip again.

But this time, what you're doing is you are passing across it urine.

And if that hormone is in the urine, it will bind to the antibody that is on the test strip.

This then causes a colour change, which shows that it's positive or negative, and we can see in the image there that again, we've got that first line appears that tells us that the test is working.

And then we've got the second line that appears, and that's showing us that that is a positive result and that person is pregnant.

Example number three then, detecting and locating molecules in cells and tissues.

So monoclonal antibodies can be made that bind with those specific molecules.

The monoclonal antibodies can then be labelled with a fluorescent dye, and we can see them in the image that we have our monoclonal antibody and then we have that fluorescent dye that is attached.

When the antibodies bind to target molecules, the dye indicates that the cell with that molecule on their surface are present.

This can be used to locate cells such as cancer cells or blood clots.

So the doctor would inject the patient with these monoclonal antibodies.

They would travel around in the blood, find that target tissue by the specific antigens on surface, and then this would give the doctor a better idea of where to find the problem and potentially remove that problem if possible.

Okay, true or false: monoclonal antibody tests can only detect pathogens.

Is that true or is that false? Can you give a reason why? I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, did you realise that that was false? And a reason why, monoclonal antibodies can be made to detect antigens on pathogens or molecules such as a hormone in pregnant women's urine, or specific molecules on cells.

Excellent, well done.

So monoclonal antibodies can also be used to treat diseases.

So for example, they might be used in the treatment of cancer.

Now, cancer patients, the tumour cells can have antigens that healthy body cells do not.

So it is a way of indicating the fact that these cells are different from other cells in the body.

If we have a look then at our healthy cells and then we have those tumour cells that are growing within that tissue mass, and on their surface, they have those different types of antigens.

The monoclonal antibodies will be produced then for these specific antigens, and so then they would be able to bind to the antigens on the tumour cells when injected into the body.

The treatment of cancer then using monoclonal antibodies can then deliver specific types of treatment to those tumour cells specifically.

And because often, and the treatment for cancer can be quite toxic, and it can cause problems for other bodily tissues, then actually, if we can take a substance directly to that tissue mass, then we're going to see more positive results.

So the monoclonal antibodies can be attached to the radioactive substances that help to reduce the size of the tumour, or the monoclonal antibody can be attached to toxic drugs or substances that stop the tumour cells dividing.

So they will then specifically go and attach to those tumour cells instead of other body cells.

Treatments that use monoclonal antibodies usually have 'mab' at the end of them in their name.

So we can see that they've got the M from the monoclonal and the A and the B from antibodies.

Traditional cancer treatments target cells that divide rapidly such as tumour cells, but there are also many healthy cells in the body that divide rapidly, including bone and skin cells.

Therefore, traditional types of cancer treatment can damage healthy bones.

So often, people will associate cancer treatments with people losing their hair, and that's also because the hair follicle actually grows very quickly and divides rapidly.

Therefore, the treatments that are provided for cancer will have an effect on the growth of hair, and that's why unfortunately, people often lose their hair.

Monoclonal antibodies were originally thought to be a magic bullet is what they called them in order to treat cancer, and people were really excited about them when they first came out.

They thought that they would deliver treatment specifically for the tumour cells, just as we've discussed.

And also, that they would leave healthy body cells alone.

Therefore, meaning that only those specific sites are going to be treated with either the radioactive or the toxic chemicals.

Unfortunately, they haven't worked quite as well as the scientists thought.

And they have caused some really serious side effects in people.

Because they are coming from the immune system of another organism like a mouse, sometimes, people's bodies are rejecting them as well.

For these reasons then, monoclonal antibody treatments have not been as widely used as originally hoped, and they are no longer thought to be the magic bullet that everyone was hoping for.

Okay, onto another check, how can we use monoclonal antibodies in cancer treatment? A, to target body cells around the tumour? B, to deliver radioactive substances to tumour cells? Or C, to deliver toxic drugs to tumour cells? I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, did you realise that it was B and C? So to deliver radioactive substances to tumour cells, and also C, to deliver toxic drugs to tumour cells.

Excellent, well done.

Onto our final task of the day then.

So number one, can you describe and explain the use of monoclonal antibodies in the detection of pregnancy? Number two, state one ethical concerns surrounding the use of monoclonal antibodies.

Number three, explain why monoclonal antibodies were originally described as a potential magic bullet but have not yet become widely used.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, so let's have a look at number one then.

Pregnant women produce the hormone HCG in their urine.

A pregnancy test has monoclonal antibodies attached to a test strip.

The monoclonal antibodies are specific to the HCG hormone.

If the urine contains HCG, it will bind to the monoclonal antibodies causing a colour change on the test strip to show a positive result.

Question number two, state one ethical concern surrounding the use of monoclonal antibodies.

Use of living animals such as mice in the production of monoclonal antibodies, that is an ethical consideration we need to make.

Number three, explain why monoclonal antibodies have been described as a potential magic bullet but have not yet become widely used.

So monoclonal antibodies can be made that target antigens found on tumour cells but not on healthy body cells.

These monoclonal antibodies can be used to deliver treatments such as radioactive substances and toxic drugs to tumour cells.

They were thought to be a magic bullet, because they would deliver treatments specifically to tumour cells and not to healthy body cells, and therefore, cause less damage.

However, monoclonal antibody treatments have caused more side effects than expected, so they are not yet widely used.

If you need to add any more to your answer, please do that now.

So we have come to the end of our lesson, and I've really enjoyed it, but I do just want to go through those key learning points with you today.

Antigens are found on the surface of all cells.

Specific antibodies are produced by lymphocytes that are complimentary to the antigen.

Monoclonal antibodies are produced by combining an antibody producing lymphocyte cell and a tumour cell to produce a hybridoma.

Scientists grow the hybridoma in culture, where it divides to make many copies of this single clone, which make monoclonal antibodies.

Monoclonal antibodies can be used to detect pathogens, to diagnose disease, and to detect other specific molecules.

For example, hormones associated with pregnancy, and molecules associated with cancer and blood clots.

Monoclonal antibodies can also be used to treat some diseases such as cancer.

I hope you've managed to get everything down today, and it's been great learning with you.

Hope to see you again soon.

Thanks, bye.