What are Monoclonal Antibodies | Production of Monoclonal Antibodies

What are Monoclonal Antibodies | Production of Monoclonal Antibodies | Advantages and Disadvantages

Monoclonal Antibodies Definition:

  • Monoclonal Antibodies are the homogeneous Antibodies produced by a single clone of plasma cells.

  • Monoclonal Antibodies are the antibodies produced by the fusion of plasma cells and myeloma cells and those cells can produce different types of Antibodies.

What are Monoclonal Antibodies?

  • We know that in a healthy body, the immune system can make antibodies. 
  • Monoclonal antibodies are artificially created antibodies intended to assist the body's natural immune system.
  • Monoclonal Antibodies are the homogeneous antibodies produced by a single clone of plasma cells.
  • Monoclonal antibodies (mAb or moAb) are identical immunoglobulins, generated from a single B-cell clone.
  • The production of monoclonal antibodies was discovered by Georges Köhler and César Milstein in 1975.
  • Tumor cells that can divide in a short time are fused with mammalian plasma cells that produce a specific antibody which results in the formation of a hybridoma cell and that cell continuously produces antibodies.
  • Those antibodies are named monoclonal because they come from only 1 type of cell, which is the hybridoma cell.
  • Examples of some naked monoclonal antibodies include trastuzumab (Herceptin, Genentech) for the treatment of stomach and breast cancers that contain the HER-2 protein and alemtuzumab (Campath, Genzyme) for the treatment of chronic lymphocytic leukemia.
  • mAbs have a monovalent Affinity that targets a specific antigen.
  • mAbs A is used to treat a wide variety of diseases, including many types of cancer, AIDS, Covid-19, etc.

History of mAb Development
  • In 1964 Littlefield developed a technique to isolate hybrid cells from 2 parent cell lines using the HAT (hypoxanthine-aminopterin-thymidine) culture media. 
  • In 1975 Kohler and Milstein discovered the clonal selection theory by fusion of normal plasma cells with myeloma cells.
  • Based on the work of Kohler and Milstein in 1986, FDA approved the first monoclonal antibody Orthoclone OKT3® (muromonab-CD3).

Steps of monoclonal antibody production

  1. Immunize animals ( Antigen Injection)
  2. Isolate spleen cells (containing antibody-producing B cells)
  3. Fuse spleen cells with myeloma cells (e.g. using PEG - polyethylene glycol) 
  4. Allow unfused B cells to die.
  5. Add aminopterin to culture to kill unfused myeloma cells.
  6. Selection of hybridoma.
  7. Multiplication of hybridoma (Grow the chosen clone of cells in tissue culture indefinitely) 
  8. Harvest antibody from the culture

Production of Monoclonal Antibodies by Hybridoma Technology

  • The production of monoclonal antibodies (mAbs) is produced by introducing an antigen to a mouse. 
  • Then, Plasma cells from the spleen are removed and fused with myeloma cells.
  • The resulting cell is called a hybridoma. 
  • Hybridoma cells are continuously growing cell lines generated by the fusion of a myeloma cell and a normal cell that are capable of producing antibodies.
  • Each hybridoma cell will produce relatively large quantities of identical antibody molecules.
  • Then, the hybridomas cells are selected by incubation in a HAT medium which only allows the growth of cells possessing the functional HPGRT gene from the DNA of B lymphocytes. 
  • On a HAT medium, only plasma cells that have fused with the engineered myeloma cells will survive in culture while others die.
  • A step of cloning by dilution leads to the choice of cells producing the monoclonal antibody desired in sufficient quantity.
  • Positive clones are multiplied on a small or large scale as needed. 
  • Lastly harvest the monoclonal antibodies from the culture.

Applications of Monoclonal Antibodies:

  • mAb is used for the diagnosis of several diseases.
  • They are used to treat several types of cancers.
  • Monoclonal antibodies are widely used to treat many disorders such as multiple sclerosis, rheumatoid arthritis, and psoriasis.
  • Monoclonal Antibodies are used for Pregnancy detection. By detecting urinary levels of human chorionic gonadotropin hormone.
  • mAb is also used to treat many hormonal disorders such as thyroxine and thyroid-stimulating hormone disorders.
  • mAbs are used to treat AIDS, Covid-19, Cancers, Asthma, etc.
  • mAbs are used for the purification of drugs by techniques called affinity chromatography.
  • Monoclonal antibodies are used to treat autoimmune diseases.

Advantages of Monoclonal Antibodies:
  • Monoclonal antibodies are cheaper to develop than conventional drugs. 
  • Side effects can be treated and reduced by using mice-human hybrid cells or by using fractions of antibodies. 
  • They bind to specific antigens.
  • They treat a wide range of diseases.

Disadvantages of Monoclonal Antibodies
  • The production of Monoclonal Antibodies is a time-consuming process.
  • There is a chance of contamination in Hybridoma culture.
  • Requirements are very expensive and need considerable effort to produce.
  • Sometimes monoclonal antibodies may not recognize the original antigen.
  • The system is only well developed for limited animals and not for other animals. 
  • More than 99% of the cells do not survive during the fusion process.

FAQs about Monoclonal Antibodies:

1. Why they are called monoclonal antibodies?
Answer: These antibodies are called "monoclonal antibodies" because they are produced by the identical offspring of a single, cloned antibody-producing cell.

2. Who Invented Hybridoma Technique?
Answer: In 1975, Kohler and Milstein first fused lymphocytes to produce a cell line that was both immortal and a producer of specific antibodies. The two scientists were awarded the Nobel Prize for Medicine in 1984 for the development of this "hybridoma.

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