Serum thymic hormone activity with systemic lupus erythematosus

Immunoregulators in the nervous system

The nervous system, through the production of neuroregulators (neurotransmitters, neuromodulators and neuropeptides) can regulate specific immune system functions, while the immune system, through the production of immunoregulators (immunomodulators and immunopeptides) can regulate specific nervous system functions. This indicates a reciprocal communication between the nervous and immune systems. The presence of immunoregulators in the brain and cerebrospinal fluid is the result of local synthesis--by intrinsic and blood-derived macrophages, activated T-lymphocytes that cross the blood-brain barrier, endothelial cells of the cerebrovasculature, microglia, astrocytes, and neuronal components--and/or uptake from the peripheral blood through the blood-brain barrier (in specific cases) and circumventricular organs. Acute and chronic pathological processes (infection, inflammation, immunological reactions, malignancy, necrosis) stimulate the synthesis and release of immunoregulators in various cell systems. These immunoregulators have pivotal roles in the coordination of the host defense mechanisms and repair, and induce a series of immunological, endocrinological, metabolical and neurological responses. This review summarizes studies concerning immunoregulators--such as interleukins, tumor necrosis factor, interferons, transforming growth factors, thymic peptides, tuftsin, platelet activating factor, neuro-immunoregulators--in the nervous system. It also describes the monitoring of immunoregulators by the central nervous system (CNS) as part of the regulatory factors that induce neurological manifestations (e.g., fever, somnolence, appetite suppression, neuroendocrine alterations) frequently accompanying acute and chronic pathological processes.

Thymopoietin to thymopentin: experimental studies

Thymopoietin is a polypeptide hormone of the thymus consisting of 49 amino acids. The pentapeptide thymopentin (TP-5) Arg-Lys-Asp-Val-Tyr, corresponding to amino acids 32-36 of thymopoietin, appears to represent the active site of thymopoietin in that it has all the biological activities of the native hormone. Thymopoietin is secreted by epithelial cells of the thymus and is pleiotropic in action, affecting neuromuscular transmission, induction of early T cell differentiation and immune regulation. The immuno-regulatory actions of thymopentin on peripheral T cells are mediated by intracellular cyclic GMP elevations in contrast to the intracellular cyclic AMP elevations induced in precursor T cells that trigger their further differentiation to T cells. Thymopoietin and thymopentin have the biological characteristics of being immunonormalizing in a number of animal model systems of immune dysbalance. These include immune dysbalances induced by thymectomy or the thymic involution associated with aging or by other procedures in thymus-intact animals. The normalizing action of thymopentin, whether the immune dysbalance be in the direction of hyper- or hyporesponsiveness, points to its potential utility in human diseases characterized by immune dysbalance.

The influence of thymic humoral factor on systemic lupus erythematosus lymphocyte function

The influence of thymic humoral factor, THF, on systemic lupus erythematosus, SLE, lymphocyte function was investigated. Increasing numbers of SLE T-cells, rosetted at 4 degrees C or 37 degrees C, were cultured with allogeneic normal B-cells and the change in IgM synthesis was assessed. Lymphocytes of some SLE patients showed improved suppression with THF when rosetted at 37 degrees C. Normal control lymphocytes did not show a net change in suppression with THF. The subgroup of SLE patients that showed improved suppression with THF in vitro might be a more appropriate group for in vivo therapeutic trials with thymic hormone, TH, than SLE patients in general.

Thymic peptide hormones: basic properties and clinical applications in cancer

The manuscript will provide an in-depth and critical review of the nomenclature, biochemistry, biological properties, and a summary of published and on-going clinical trials with all reported thymic preparations, including both partially purified thymic factors (e.g., thymosin fraction 5, thymostimulin) as well as purified and synthesized thymic peptides (e.g., thymosin alpha 1, thymulin). Particular emphasis will be placed on which thymic peptides should be categorized as true hormones. In addition, the comparative biochemistry and biological activity in animals will be summarized and contrasted for all the currently available thymic factors. The effects, in vitro of thymic factors, on peripheral blood lymphocytes isolated from normal donors and patients with primary immunodeficiency disorders, autoimmune disorders, and neoplastic disorders will also be reviewed. Finally, a detailed critical summary of the clinical trials performed with each of the thymic preparations will be presented with an emphasis on treatment of patients with cancer.

Immunoassay for bovine serum thymopoietin: discrimination from splenin by monoclonal antibodies

A polyclonal rabbit anti-bovine thymopoietin antiserum was used to develop a radioimmunoassay and sandwich enzyme-linked immunosorbent (ELISA) assay for the thymic hormone thymopoietin. Both assays showed slightly less sensitivity for the closely related splenic hormone splenin (SP) than thymopoietin (TP) and markedly less sensitivity for the human as compared with the bovine polypeptides. A number of murine monoclonal antibodies specific for bovine thymopoietin were generated; they were unreactive with bovine splenin and were also unreactive with human thymopoietin and splenin. A sandwich ELISA using these monoclonal anti-TP antibodies together with polyclonal rabbit anti-TP was specific for bovine thymopoietin and measured 300-500 ng/ml thymopoietin in bovine serum. Similar approaches are being pursued to develop an immunoassay for thymopoietin in human serum.