ployclonal and monoclonal antibodies?

Question

what are polyclonal and monoclonal antibodies and what are they used for?

Answer 1

Polyclonal

Polyclonal antibodies are antibodies that are derived from several different t B-cell lines. The selections of antibody molecules bind to different parts of the antigen, with different binding affinities. Within a polyclonal sample, some of the antibodies will be specific for the antigen with which the animal was immunised. The rest of the antibodies have been obtained from meetings with other foreign antigens that the animal has been exposed to through its life time.

The production of polyclonal antibodies begins with the immunisation of an animal, usually a rabbit. Once the rabbit has been immunised, it is restrained in a special cage and its ear is prepared for removing a blood sample from the animal. A razor blade is used to cut the vein on the rabbit’s ear. The blood is then collected in glass tubes so the blood can clot, as this will be more efficient and more serum can be obtained with minimal hemolysis. When the blood clots a wooden applicator is used to rim the edges of the clot, this step is important, as it results in getting the maximum amount of serum from the blood. The antibodies are then purified directly from the serum.

There are some advantages for using polyclonal antibodies, however there are also
disadvantages. Some advantages of using polyclonal antibodies are:


Advantages

* After as little as 2-3 months after the initial immunisation of the animal, multiple
subclass and high affinity polyclonal antibodies can be isolated.

* Polyclonal antibodies are relatively inexpensive to produce.

* From one immunised animal, large quantities of polyclonal antibodies can be
produced. (up to 10mg/ml)

* Polyclonal antibodies provide an overall look at an immune response, due to them
containing an entire antigen specific population


Some disadvantages from using polyclonal antibodies are:


Disadvantages

* To obtain the correct specificity, the antibodies have to be highly purified

* The amount of antibodies that can be obtained are limited to the life span of the
immunised animal

* Polyclonal antisera recognises many antigenic determinants, making it difficult to
study individual parts of the complex antigens.

* As a result of changes in antibody affinity, specificity, and subclass, different
bleedings have to be characterised individually


Monoclonal


Unlike polyclonal, producing monoclonal antibodies is a much more complex process. Monoclonal antibodies are produce from one clone of cells rather than many different clones like polyclonal antibodies. This results in the antibody molecules being exactly the same and they bind to the same antigenic site with identical binding affinities. To produce monoclonal antibodies, clones of a single hybrid cell are formed in a laboratory. This is achieved by fusing a B cell with a tumour cell.

The process involves repeatedly immunising an inbred mouse with an antigen. After several immunisations the animal’s spleen is removed. The spleen is then removed as it is produces the B-cells. Due to the spleen cells not being able to be cultured, the cells are combined with myeloma cells. The combination results in the production hybridoma cells. Hybridoma cells that produce antibodies that are not specific for the antigen are easily screened out with an ELISA, making it easier to find the antibodies specific to the antigen. Once a selected, a single hybridoma line is injected into a healthy mouse. The injection causes a tumour to grow inside the mouse. This is due to hybridoma cells and myeloma cells being able to produce tumours. As the tumour grows it produces a fluid which is full of monoclonal antibodies. This fluid is known as ascites. Monoclonal antibodies are produced due to the hybridoma cell being produced from a single B-cell.

Some advantages of monoclonal antibodies are:

Advantages


* Antibodies with low–affinity binding can be selected during screening procedures,
which is of benefit. This is due to the antibodies being designed for
immunoaffinity chromatography

* Since immortal cell lines can theoretically be developed, large amounts of
antibodies can be produced.

* Due to their immortal nature, hybridoma cells can be frozen, and then thawed for
use.

* To study one particular domain of a specific part of an antigen, only one specific
antibody is required.



Some disadvantages of the monoclonal antibodies:

Disadvantages

* Monoclonal antibodies do not bind easily to the antigens as they have a lower
affinity than polyclonal antibodies.

* Producing monoclonal antibodies is both time consuming and expensive.

* The antigenic determinant site can be shared with a selection of different antigens
which are not related to the antigen required for study.

* Hybridoma cells lines are known to be unstable. This instability may be caused by
the loss of chromosomes or possible contamination of the tissue culture.

When choosing whether to use polyclonal or monoclonal antibodies, it really depends on the experimental situation. As mentioned before, both approaches offer certain advantages as well as disadvantages. When it comes to the amount of antibodies that can be obtained from a sample, monoclonal antibodies have the upper hand. This is due to the amount of polyclonal antibodies that can be obtained, are limited to the life span of the immunised animal. However, monoclonal antibodies have an immortal nature. This means the hybridoma cells can be frozen and stored, then thawed and recultured in vitro which in turn provides a constant and renewable source of antibodies for study purposes, without having to go through the time consuming and expensive process again. In view of this, polyclonal antibodies are relatively inexpensive to produce and can be isolated after as little as 2-3 months after the animals initial immunisation. When it comes to producing both polyclonal and monoclonal antibodies, many ethical issues are raised. In producing monoclonal antibodies two mice are needed for the procedure, and as mice are used in abundance in science they are more than likely not to survive the procedure. Whereas in making polyclonal antibodies, one rabbit is used and survives the procedure. However this does limit the amounts of antibodies that can be obtained to the life span of the immunised animal.

Answer 2

You can expose antigens to different populations of B Cells, and they will produce different antibodies to the same antigen, because they recognize different epitopes (=different regions on antigen). This collection of Ab will be polyclonal: different specifity, different affinity (avidity), different Ig class even.

Now, monoclonal Ab would be a collection of Abs made from the same line of B Cells. They would all recognize the same epitope on an Ag, they would all be of the same Ig class, etc. Polyclonal are made from any B Cells.

Monoclonal Ab's are good for quantitative analyses and ELISAs to detect how much Ag is present in a sample, because specificity is important.

Polyclonal Abs may have a better clinical use, because they can recognize a wider variety of epitopes.
Polyclonal Ab's

Answer 3

using antibodies (or any immunoserum) is continually very risky because of the phenomenon of rejection. you're injected element of a immune gadget, which will see you as overseas body, purely as your human being immune gadget will see it as overseas... Follows an really undesirable bout of battling which does fairly some damage, it truly is that if it does no longer finally end up killing you, nastily and fairly quick. it really is why remedies of this type are quite somewhat nerver tried. there is also the question of low bioavailability of peptides, which has a tendency to get degraded, and by no ability purely in the time of passage by the tummy. save in ideas also that each and every one recombinant peptide drugs are quite severe priced to produce. For this a bacterial gadget should be designed for mass production (to make prices a minimum of a touch attainable), and some proteins are litterally no longer attainable to produce wisely in bacteria. nevertheless some organizations have tried such issues, yet so a techniques fulfillment has been very modest compared to the funding needed to develop the medication.

Answer 4

They are an essential part of the immune system

Answer 5

they both fought in the war of the roses