Use of Monoclonal Antibodies Against Autoimmune Diseases By: Kelly Sambuchi ISAT 351 Spring 1999

Outline n Terminology n Introduction n What is Autoimmune Disease? n Use of Monoclonal Antibodies n Case Studies n Summary n Conclusion

Terminology n Hybrids: The fusion of two cell membranes and two dissimilar nuclei n Monoclonal Antibodies: Developed as a hybrid, cell that will bind to a specific site and produce antibodies in larger quantities n Immune System: System that defends against foreign agents that infect the body

Terminology (cont.) n Autoimmune Disease: Result of a malfunctioning immune system that has in effect “lost control” of its necessary responses.

Introduction n Why monoclonal antibodies? n For many years scientists had been creating cell hybrids for scientific research. These cell hybrids were functional for research purposes, maintaining some properties of each parent cell, however they would loose some chromosomes in production. n In 1975 two scientists Kohler and Milstein discovered monoclonal antibodies

The Discovery n Kohler and Milstein attempted to fuse together antibody producing mouse spleen cells with mouse myeloma cells n They discovered with this fusion they had created a cell which “secreted antibodies of the specificity dictated by the parent spleen cell, but in the quantity characteristic of a myeloma cell (Hurrell)”

Autoimmune Disease n In a normal immune system two cells play vital roles in the response to invading agents n The first cell is the B lymphocyte cell n The second cell is the T lymphocyte cell

The B Lymphocyte Cell In A Normal Immune System n When a foreign substance is identified in the body B cells produce antibodies which will attack the foreign molecule forming antigen aggregates n Both the antibodies and antigen aggregates are taken in by the phagocytic cells and fused with lysosomes to be digested

The B Lymphocyte Cell In A Malfunctioning Immune System n The B cell will produce autoantibodies, which react with the individuals own tissue rather than the foreign substance n These autoantibodies will deposit within the tissue, which in turn produces an inflammatory response in the tissue resulting in tissue damage

The T Lymphocyte Cell In A Normal Immune System n Similar to B cells, T cells are activated by the presence of a foreign substance n A foreign substance is recognized by the receptor found on the surface of the T cells n T cells undergo thymic education, where they are programmed to activate when they encounter a particular foreign substance

T Lymphocyte Cells In A Malfunctioning Immune System n Thymic education can be thought of as a screening processes, T cells that exit the thymus have been properly programmed and can be thought of as “good” T cells n Occasionally “bad” T cells exit the thymus n These T cells have a high affinity for self molecules

T Lymphocyte Cells In A Malfunctioning Immune System n T cells with a high affinity to self molecules will react with an individuals own tissue –Expressing a CD4 Receptor targeted to Major Histocompatibility Complex II n When “bad” T cells are activated they signal the B cell to produce the autoantibodies which in turn attack healthy tissue, resulting in autoimmune disease

A Second Method To The Development of a Malfunctioning Immune System n In the event that no “bad” T cells exit the thymus, autoimmune disease can still occur n This occurs when T cells in a tolerant state become activated by the stimulus of a large infection, such as a life threatening illness n If T cells do not return to a tolerant state after the infection clears, they will still be targeted to the now healthy tissue

The Use of Monoclonal Antibodies Against Autoimmune Diseases n A monoclonal antibody is produced through the fusion of a B cell with an antigen and a cell with a B cell tumor n Thus, creating a “missile” cell that will hone in on a specific “target” n What does this mean for Autoimmunity?

The Use of Monoclonal Antibodies Against Autoimmune Diseases n If a monoclonal antibody where to be “targeted” to bind to the CD4 receptor of “bad” T cells it could bind to the receptor blocking it n By blocking the receptor the monoclonal antibody has prevented the receptor from further binding to the MHC-II site, preventing activation n Without activation it would be unable to clone itself, and would enter a state of tolerance

Case Studies n Throughout the last several decades many treatments have been attempted to alleviate the symptoms of Autoimmune Disease with little success –Corticosteroid Drugs –Ionizing Radiation –Surgical Excision

Case Study 1 n Rheumatoid Arthritis –Double-blind, Placebo Clinical Trial n Patients Received –Placebo or Chimeric Monoclonal Antibody known as cA2 n Dosages –5, 10 or 20 mg/kg n Analysis –NOS 2 Protein and NOS Enzyme Activity

Results of Case Study 1 n The analysis concluded that there were significant changes in the NOS activity of patients who received the chimeric monoclonal antibody, resulting in decreased joint tenderness, a common effect of Rheumatoid Arthritis

Case Study 2 n Rheumatoid Arthritis –Double-blind, Placebo random selection n Patients Received –Non-depleting Monoclonal Antibody (Mab) –Placebo n Dosages –450 mg (Mab) n Analysis –Production of mitogen-stimulated peripheral blood T cells

Results of Case Study 2 n The results clearly showed an immediate decrease in CD4 reactive protein levels by those individuals who originally received the anti-CD4 Mab, as well as clinical benefits.

Summary n The continued efforts of scientists and research laboratories around the world, as well as the funding of nonprofit organization such as the AARDA will hopefully eventually determine a cure as well as improved diagnostics against Autoimmunity. The monoclonal antibody is a new concept in the world of science, having been discovered in The increased awareness of the monoclonal antibodies and its numerous possible applications will only continue in this field of biotechnology.

In Conclusion n The studies performed using monoclonal antibodies against Autoimmune Disease have shown remarkable results. In the various case studies presented in this paper all showed improvement in the patients receiving the various treatments and little to no change in the placebo groups. Studies such as these, which prove the increased possibilities of monoclonal antibodies, can only help to further study this area of science. It is only when studies prove effective that research continues, thus the field of biotechnology exploring monoclonal antibodies and their uses continues.

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