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Lymphocyte T-Cell Immunomodulator (LTCI, Lymphocyte T-Cell Immunomodulator) is an immune regulating polypeptide manufactured and distributed by T-Cyte Therapeutics . Lymphocyte T-Cell Immunomodulator is a potent regulator of CD-4 lymphocyte production and function. It has been shown to increase lymphocyte numbers and Interleukin-2 (IL-2) production in animals.
Prior to 1960 the thymus gland, which lies in the cervical thoracic area, was thought to be of little importance. In adult animals the thymus is almost non-existent because it atrophies as animals reach adulthood. It was observed, however, that when pre-adolescent animals are thymectomized they experience a variety of maladies including increased incidence of infection, failure to grow, neuromuscular disorders, cancer, etc., collectively known as “wasting disease”. The greater susceptibility to infection was shown to be directly attributable to a dramatic decrease in peripheral blood lymphocytes in thymectomized animals.
By 1964 it had been demonstrated that regulatory factors extracted from the thymus gland could prevent many of the manifestations of wasting disease. This suggested that the thymus produces substances important in the development of immunity. It was not until 1971 that it was discovered that thymus-derived lymphocytes (T-cells) were important regulators of bone-marrow-derived antibody-producing lymphocytes (B-cells). After the discovery that the thymus was producing profound regulatory factors, several groups of scientists began trying to extract and purify this factor from thymus glands in much the same manner that insulin was prepared from the pancreas for therapeutic use in diabetes. The difficulty was that the thymus is a very small gland and produces very small quantities of the factor. Thus, purification techniques did not allow appropriate pure fractions to be produced in sufficient quantities.
In veterinary medicine, wasting syndrome is also recognized and is thought to be associated with infectious canine hepatitis virus infection, feline infectious peritonitis virus infection, and feline leukemia virus infections. In cases of feline infectious peritonitis, necrotizing lesions in the thymus is often a consequence of early stages of the disease. Additionally, the thymus is a preferred tissue for viral replication of feline immunodeficiency virus, which results in lesions and dysfunction.
In 1983 scientists succeeded in cloning epithelial cell lines from the thymus of various species and began to biochemically and biologically characterize these thymus derived regulatory factors. A protein with a molecular weight of about 50,000 daltons was subsequently described and shown to augment the immune responses of both immature and mature T-cells. This protein came to be known as Lymphocyte T-Cell Immunomodulator (LTCI).
Normally a proportion of immature thymus-derived lymphocytes differentiate into mature CD-4+ T-cells which produce a number of cytokines, including interleukin-2 (IL-2) and gamma interferon. CD-4 cells coordinate the overall immune response and help activate CD-8 T-lymphocytes, which attack viruses and tumor cells. CD-8+ T-lymphocytes are often called “effector” or “cytotoxic” T-cells, because they respond to intracellular pathogens and cancer cells. Under viral attack CD-4+ T-cells fail to mature, fail to produce IL-2 and gamma interferon, and consequently fail to coordinate CD-8 responses to viruses. Because LTCI increases the production of CD-4+ T-cells, this immunosuppression can be overcome by treatment.
Because of its action on CD4+ T-cells, LTCI also promotes hematopoiesis. It is hypothesized that CD4+ T-cells may regulate the production of all blood cell types in the bone marrow, including red blood cells, platelets, and granulocytes. A deficiency in CD-4+ T-cells thus could lead to the anemia observed in immune compromised subjects including cancer patients undergoing chemotherapy, or viral or other chemically induced conditions.
In summary, the primary action of LTCI is directed toward the mature T lymphocyte production and activation, resulting in increased production of IL-2 and interferon in physiological amounts and ratios. These cytokines stimulate a cascade of events that enhance or potentiate both cell mediated immunity as well as antibody-mediated responses.
Lymphocyte T-Cell Immunomodulator is a single chain polypeptide. It is a strongly cationic glycoprotein, and is purified with cation exchange resin. Purification of protein from bovine-derived stromal cell supernatants produces a substantially homogeneous factor, free of extraneous materials. The bovine protein is homologous with other mammalian species and is a homogeneous 50 kDa glycoprotein with an isoelectric point of 6.5. The protein is prepared in a lyophilized 1 microgram dose. Reconstitution in sterile diluent produces a solution for subcutaneous injection.
LTCI is manufactured and distributed exclusively by T-Cyte Therapeutics, Inc. LTCI has been conditionally approved by the United States Department of Agriculture (USDA) as an aid in the treatment of cats infected with feline leukemia virus (FeLV) and/or feline immunodeficiency virus (FIV), and the associated symptoms of lymphopenia, opportunistic infection, anemia, granulocytopenia, or thrombocytopenia. Practitioners have successfully used LTCI in a number of problematic disease conditions affecting cats, dogs and horses, including:
The results from an early clinical trial conducted on twenty-one thoroughbred racehorses (fifteen suffering from chronic Exercise Induced Pulmonary Hemorrhage, six of whom were diagnosed with various forms of Upper Respiratory Disease) were impressive when judged by the effectiveness of the LTCI protein versus other products on the market used to treat horses with the illness. Six were foals suffering from forms of this life-threatening pneumonia, thought to be Rhodococcus or hemolytic Streptococcus.
Following LTCI treatment, all but one of the horses returned to work or racing, with none of the tracheal hemorrhaging that had plagued them. The researchers were really happy that five of the six gravely ill foals made uneventful recoveries. Unfortunately, the foal that died was beyond hope from the outset and was lost within 24 hours.
Veterinarians and pet owners from around the country, actually from around the world, have been reporting significant positive responses to LTCI. The one dispiriting element is when the disease processes are allowed to progress too far before treatment, leaving no hope for improvement. While LTCI is labeled for use for FeLV and FIV, once veterinarians understand LTCI’s mode of action and safety, practitioners envision the off-label potentials in treating other, equally cruel diseases. No adverse event has ever been reported following the use of LTCI and it is postulated that LTCI could benefit EHV cases as well as outbreaks of Canine Influenza. The early trial results are promising and very intriguing. Hopefully, a further trial will prove the potential of LTCI as a major medical breakthrough in the field of immunotherapy, not only as has been shown for cats, but also to help control other inflammatory diseases in dogs, including arthritis, and EPM, endotoxemia, and laminitis in horses.
The manufacturer encourages questions regarding the use of LTCI. Veterinarians may order LTCI at www.TCyte.com or by phone (1-800-483-2104). Streamlined ordering enables practitioners to quickly receive the most advanced product for the care and treatment of FeLV and/or FIV, of great significance in cases of critically ill patients.
T-Cyte Therapeutics (www.TCyte.com) is dedicated to providing safe, effective, science-based products that enhance the health of animals, allowing owners to enjoy their longer-lived and healthier animals. In the worldwide medical community’s scramble to find a cure for the deadly HIV/AIDS pandemic, scientists used the Feline Leukemia Virus (FeLV) and Feline Immunodeficiency Virus (FIV) as research models for the human diseases. Advances in understanding the immune system were moving at break-neck speed. Even before this all-out race, Dr. Terry Beardsley, as a graduate researcher specializing in immunology at Baylor College of Medicine, had set out to discover a biological treatment pathway that emulated the body’s own natural defense processes, a discovery that could reverse the fatal effects of severe combined immune deficiency disease (SCID). This work resulted in a better understanding of bone marrow transplantation and the function of the thymus gland. While a faculty member at UCLA, Dr. Beardsley demonstrated that: retrovirus infection alters the structure of the thymus gland and its ability to produce mature, functional T-Cells; and retrovirus infection of thymic epithelial cells caused defective T-Cell development, leading to immune deficiency and/or leukemia. He ultimately proved that the destruction of thymic epithelium is a major contributor to failure of immune regeneration in AIDS. At the University of California, Dr. Beardsley refined this cellular theory and was the first scientist to clone thymic epithelial cells, successfully identifying and describing one of the immunoregulatory proteins involved in the process and the type of cells that produced it: Peptides extracted from thymus gland cells could control the immune system’s response to viral attack, culminating in a landmark publication of Dr. Beardsley’s research findings in The Proceedings of the National Academy of Science. With anti-HIV drug cocktails promising hope for HIV/AIDS patients, Beardsley studies had shown that his Lymphocyte T-cell Immunomodulator (LTCI) molecule could be used as a therapy for the treatment of immunocompromised cats. He formed T-Cyte Therapeutics, Inc. to develop LTCI and treat the devastating effects of FeLV and FIV viruses. Until LTCI was granted a conditional license by the USDA, there was no effective treatment of the disease or its symptoms; practitioners could only prescribe palliative care, isolation, and ultimately, euthanasia. LTCI is able to enhance the immune status of FeLV/FIV-infected cats, with a corresponding, significant improvement in clinical symptoms. The therapeutic effects appear to be long-lasting and without side effects.