Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
1997-11-20
2002-08-20
Berch, Mark L. (Department: 1624)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
C544S277000
Reexamination Certificate
active
06436947
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to certain Trans cyclopentanyl purine analogs which are useful as immunosuppressants.
BACKGROUND OF THE INVENTION
Immunity is concerned with the recognition and disposal of foreign antigenic material which is present in the body. Typically the antigens are in the form of particulate matter (i.e., cells, bacteria, etc.) or large protein or polysaccharide molecules which are recognized by the immune system as being “non-self”, i.e., detectably different or foreign from the animals own constituents. Potential antigens can be a variety of substances, often proteins, which are most frequently located on the outer surfaces of cells. For example, potential antigens can be found on pollen grains, tissue grafts, animal parasites, viruses, and bacteria. Once the antigenic material is recognized as “non-self” by the immune system, natural (non-specific) and/or adaptive immune responses can be initiated and maintained by the action of specific immune cells, antibodies and the complement system. Under certain conditions, including in certain disease states, an animal's immune system will recognize its own constituents as “non-self” and initiate an immune response against “self” material.
An immune response can be carried out by the immune system by means of natural or adaptive mechanisms, each of which are composed of both cell-mediated and humoral elements. Natural mechanisms for immune response refer to those mechanisms involved in essentially non-specific immune reactions which involve the complement system and myeloid cells alone, such as macrophages, mast cells and polymorphonuclear leukocytes (PMN), in reacting to certain bacteria, viruses, tissue damage and other antigens. These natural mechanisms provide what is referred to as natural immunity. Adaptive mechanisms for immune response refer to those mechanisms which are mediated by lymphocytes (T and B cells) and antibodies which can respond selectively to thousands of different materials recognized as “non-self”. These adaptive mechanisms provide what is referred to as adaptive immunity and lead to a specific memory and a permanently altered pattern of response in adaptation to the animal's own environment. Adaptive immunity can be provided by the lymphocytes and antibodies alone or, more commonly, can be provided by the interaction of lymphocytes and antibodies with the complement system and myeloid cells of the natural mechanisms of immunity. The antibodies provide the humoral element of the adaptive immune response and the T-cells provide the cell-mediated element of the adaptive immune response.
Natural mechanisms of immune response involve phagocytosis by macrophages and PMN whereby foreign material or antigen is engulfed and disposed of by these cells. In addition, macrophages can kill some foreign cells through its cytotoxic effects. The complement system which is also involved in natural immunity is made up of various peptides and enzymes which can attach to foreign material or antigen and thereby promote phagocytosis by macrophages and PMN, or enable cell lysis or inflammatory effects to take place.
Adaptive mechanisms of immune response involve the actions against specific antigens of antibody secreted by B-lymphocytes (or B-cells) as well as the actions of various T-lymphocytes (or T-cells) on a specific antigen, on B-cells, on other T-cells and on macrophages.
Antibodies, which are responsible for the humoral aspect of adaptive immunity, are serum globulins secreted by B-cells with a wide range of specificity for different antigens. Antibodies are secreted in response to the recognition of specific antigens and provide a variety of protective responses. Antibodies can bind to and neutralize bacterial toxins and can bind to the surface of viruses, bacteria, or other cells recognized as “non-self” and thus promote phagocytosis by PMN and macrophages. In addition, antibodies can activate the complement system which further augments the immune response against the specific antigen.
Lymphocytes are small cells found in the blood which circulate from the blood, through the tissues, and back to the blood via the lymph system. There are two major subpopulations of lymphocytes called B-cells and T-cells. B-cells and T-cells are both derived from the same lymphoid stem cell with the B-cells differentiating in the bone marrow and the T-cells differentiating in the thymus. The lymphocytes possess certain restricted receptors which permit each cell to respond to a specific antigen. This provides the basis for the specificity of the adaptive immune response. In addition, lymphocytes have a relatively long lifespan and have the ability to proliferate clonally upon receiving the proper signal. This property provides the basis for the memory aspect of the adaptive immune response.
B-cells are the lymphocytes responsible for the humoral aspect of adaptive immunity. In response to recognition of a specific foreign antigen, a B-cell will secrete a specific antibody which binds to that specific antigen. The antibody neutralizes the antigen, in the case of toxins, or promotes phagocytosis, in the case of other antigens. Antibodies also are involved in the activation of the complement system which further escalates the immune response toward the invading antigen.
T-cells are the lymphocytes responsible for the cell-mediated aspect of adaptive immunity. There are three major types of T-cells, i.e., the Cytotoxic T-cells, Helper T-cells and the Suppressor T-cells. The Cytotoxic T-cells detects and destroys cells infected with a specific virus antigen. Helper T-cells have a variety of regulatory functions. Helper T-cells, upon identification of a specific antigen, can promote or enhance an antibody response to the antigen by the appropriate B-cell and it can promote or enhance phagocytosis of the antigen by macrophages. Suppressor T-cells have the effect of suppressing an immune response directed toward a particular antigen.
The cell-mediated immune response is controlled and monitored by the T-cells through a variety of regulatory messenger compounds secreted by the myeloid cells and the lymphocyte cells. Through the secretion of these regulatory messenger compounds, the T-cells can regulate the proliferation and activation of other immune cells such as B-cells, macrophages, PMN and other T-cells. For example, upon binding a foreign antigen, a macrophage or other antigen presenting cell can secrete interleukin-1 (IL-1) which activates the Helper T-cells. T-cells in turn secrete certain lymphokines, including interleukin-2 (IL-2) and &ggr;-interferon, each of which have a variety of regulatory effects in the cell-mediated immune response. Lymphokines are a large family of molecules produced by T-cells (and sometimes B-cells) including
IL-2, which promotes the clonal proliferation of T-cells;
MAF or macrophage activation factor, which increases many macrophage functions including phagocytosis, intracellular killing and secretion of various cytotoxic factors;
NAF or neutrophil activation factor, which increases many functions of the PMN including phagocytosis, oxygen radical production, bacterial killing, enhanced chemotaxis and enhanced cytokine production;
MIF or macrophage migration factor, which by restricting the movement of macrophages, concentrates them in the vicinity of the T-cell;
&ggr;-interferon, which is produced by the activated T-cell and is capable of producing a wide range of effects on many cells including inhibition of virus replication, induction of expression of class II histocompatibility molecules allowing these cells to become active in antigen binding and presentation, activation of macrophages, inhibition of cell growth, induction of differentiation of a number of myeloid cell lines.
Activated macrophages and PMNs, which provide an enhanced immune response as part of the cell-mediated adaptive immunity, are characterized as having increased production of reactive oxygen intermediates. This increased production of reactive oxygen intermediates, or respiratory burst,
Borcherding David R.
Cole Douglas L.
Edwards III Carl K.
Esser Ronald E.
Aventis Pharmaceuticals Inc.
Berch Mark L.
Darkes Paul R.
Payne T. Helen
LandOfFree
Trans cyclopentanyl purine analogs useful as immunosuppressants does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Trans cyclopentanyl purine analogs useful as immunosuppressants, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Trans cyclopentanyl purine analogs useful as immunosuppressants will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2916821