Thymus Extract Research Articles

Steroid economising effects of a serous calf thymus extract in two patients with systemic juvenile chronic arthritis (M.Still)

Steroid economising effects of a serous calf thymus extract in two patients with systemic juvenile chronic arthritis (M.Still)

Effect of thymic extract thymostimulin (TP-1 R) on immune response of mice with prolonged Immunosuppression induced by the cytotoxic drug- CCNU

Effect of thymic extract thymostimulin (TP-1 R) on immune response of mice with prolonged Immunosuppression induced by the cytotoxic drug- CCNU

T-dependent immunity in aged humans. I. Evaluation of T-cell subpopulations before and after short term administration of a thymic extract.

T lymphocytes, T lymphocyte subpopulations and delayed hypersensitivity reactions to recall antigens were studied in 20 aged subjects clinically unaffected by disorders of the immune system. T-cells evaluated by the sheep rosette test and absolute T-cell number were within normal range. T-cell subsets were studied by the high affinity rosetting test and by the sheep rosette test after pre-incubation with theophylline; such methods have been shown by others to discriminate between T-cells with helper or suppressor activity. We did not observe an imbalance of such subpopulations. Skin reactivity to recall antigens (Candida and SK-SD) was depressed in several cases. Since a decline in serum levels of thymic hormones has been reported in the ageing and it is suggested that this could account for the T-dependent immunity defect, we treated these patients with a bovine thymic extract (thymostimulin, TP-1) 1 mg/kg/day for three consecutive days. Immunological tests were performed again after this therapy but no modifications were observed. We may conclude that the aged subjects studied in this paper present normal relative and absolute number of T-cells and T subpopulations, whereas the function of T-cells, as assessed by skin reactivity to recall antigens is often depressed. Short term therapy with TP-1 at the above mentioned dosage was ineffective in modifying the parameters analysed.

In vitro differentiation of human marrow T cell precursors by thymic factors in severe combined immunodeficiency.

Marrow cells from 16 patients with severe combined immunodeficiency diseases (SCID) were examined for the presence of T cell precursors which could be induced to express surface markers and functions of T lymphocytes after exposure in vitro to thymic extracts or peptides of thymic origin (thymopoietin and thymopoietin32-36 (TP-5). Marrow cells from 14 patients studied before transplantation revealed three patterns of response. In five patients, inducible T cell precursors were not detected. In six patients, precursors were detected which could be induced to express a human T lymphocyte antigen (HTLA) but acquired little or no ability to rosette with sheep erythrocytes (SRBCs). Induction of HTLA-positive and E rosette-positive lymphocytes was normal in only two patients, both of whom were engrafted with maternal lymphocytes as an apparent result of an intrauterine infusion. Induction of mixed leukocyte reaction (MLR) responses following exposure to thymic hormones was also observed in one of these two patients. In no case could significant responses to mitogens be elicited. Following transplantation, marrow cells from fully engrafted, immunologically reconstituted patients could be induced to bear HTLA, to form E rosettes, and to respond to mitogens and allogeneic cells following exposure to thymic extracts, thymopoietin, or TP-5. Thus, most patients with SCID manifest differentiative abnormalities intrinsic to lymphoid precursors which are corrected following engraftment of functioning allogeneic lymphoid precursors from normal donors.

Immunological detection of a conserved structure for terminal deoxynucleotidyltransferase.

The polypeptide structure of terminal transferase in crude extracts of thymus or cultured cells was examined by electrophoresis on polyacrylamide gels in the presence of sodium dodecyl sulfate, electrophoretic transfer of separated peptides to nitrocellulose, specific labeling with rabbit anti-calf thymus terminal transferase, and visualization with an immunoperoxidase reaction. The major form of terminal transferase detected in crude extracts or enzyme fractions after phosphocellulose chromatography is a single 58,000- to 60,000-dalton peptide for calf thymus, rat thymus, mouse thymus, chicken thymus, cat thymus, human lymphoblastoid cells, and mouse lymphoblastoid cells. Since the anti-calf thymus terminal transferase antibody was prepared against a homogeneous calf thymus enzyme consisting of two polypeptide chains in a hydrodynamic structure of Mr = 32,000, these results suggest that the homogeneous calf thymus enzyme preparation is a proteolytically degraded form of the 58,000-dalton peptide. Terminal transferase peptides from human, bovine, rat, chicken, cat, and mouse are immunologically related and have similar conserved polypeptide structure.

Lyt-2 and lyt-3 antigens are on two different polypeptide subunits linked by disulfide bonds. Relationship of subunits to T cell cytolytic activity.

Lyt-2 and Lyt-3 antigens are carried on separate disulfide-bonded subunits of the same cell surface macromolecules. These are present on thymocytes in a variety of multimeric forms consisting of disulfide-bonded dimers, tetramers, and hexamers of pairwise combinations of three subunits (30,000, 34,000, and 38,000 Mr). From reduced and alkylated Nonidet-P40 thymus extracts, a monoclonal anti-Lyt-3 precipitates only the 30,000 Mr subunit, but not the 30,000 Mr subunit. Almost all of the Lyt-2 and Lyt-3 subunits on the cell are covalently linked by disulfide bonds. However, small amounts of free Lyt-3 subunit was seen in some experiments. Similarly, small amounts of Lyt-2-3- material, consisting of dimers of the 38,000 and 34,000 Mr subunits were identified. Each of the three subunits migrated with a basic charge (pI greater than 8) on two-dimensional gels. Cytotoxic effector cells that are blocked by anti-Lyt-2 and anti-3 can be treated with trypsin and other arginine-specific proteases to remove these antigens. At low concentrations of these proteases, Lyt-3 antigens are selectively removed. After selective removal of Lyt-3 antigens, cytotoxic effector cells are still active and blocking of activity by anti-Lyt-3 is significantly reduced, whereas blocking of activity by anti-Lyt-2 is significantly increased. Neither Lyt-2 nor Lyt-3 is allelically excluded on thymocytes or T cells. These results suggested that the Lyt-2, Lyt-3 macromolecules are associated with but do not serve as the T cell antigen receptor.

Stimulatory effect on DNA synthesis of thymus and spleen extract from leukemic AKR mice

A 30,000-50,000 molecular weight (MW) extract of thymus and spleen from 11 age groups of untreated AKR mice, 1-210 days old, was tested for in vitro effect on thymidine incorporation into normal AKR lymph node cells, normal spleen cells, and leukemic thymocytes. Extracts from mice up to 5 months of age mostly had slightly inhibitory effect but concomitant with emergence of thymus leukemia in the 6-month-old mice, the extract acquired a strongly mitogenic effect on normal lymph node cells. Seven-month-old, non-leukemic animals again yielded extracts with inhibitory effect.

Inhibition of lymphocyte production via thymic factors.

A protein fraction capable of inhibiting both in vitro and in vivo lymphocyte DNA synthesis was purified, starting from a particle-free crude water extract of calf thymus and using selective precipitations with ethanol and ammonium sulphate. The semipurified T4-P2 fraction showed a preferential inhibitory activity in rat thymocyte DNA synthesis, and to a lesser extent in bone marrow and newborn rat liver cells. Non-hemopoietic cell types proved to be insensitive to T4-P2. In addition similar mouse tissue extracts (P2 fractions from testes, kidney, liver, and lung) had no effect on the spontaneous thymocyte proliferation indicating the tissue specific presence of the bioactive factor. PHA-induced T-lymphocyte proliferation was transitorily inhibited at the late G1 and S phase of the mitotic cell cycle. Also, this fraction proved to be active in decreasing the3H-thymidine incorporation into the thymus and spleen DNA time dependently after a single in vivo administration.

Multiple species of ornithine decarboxylase in rat tissues: Effects of dexamethasone

Several species of ornithine decarboxylase were separated by chromatography of rat thymus and kidney extracts on DEAE-Sepharose CL-6B. One major and one minor species were absent from thymus of rats two hours after hormone treatment but otherwise, the elution profile was identical to thymus from control animals. The elution patterns of ODC activity in kidneys of rats treated 2.5 or 5 hours before sacrifice with dexamethasone differ from that of control kidney and from each other. Enzyme from kidneys early after hormone treatment is eluted earlier than enzyme from control tissue, while at 5 hours, the enzyme is eluted much later than in the control. This suggests that the hormone-induced activity is subsequently modified.

Childhood histiocytosis X: clinical aspects and therapeutic approaches.

Childhood histiocytosis X is a disorder of the monocyte-macrophage system with various clinical aspects and immunological abnormalities. The disease may be localized or disseminated, with an acute, subacute, or chronic course which can lead to death or many residual damages. Therapy depends on the extent of the disease and risk factors such as involvement of the lung, the liver, and the hematopoietic system. For localized lesions in the bone no therapy except surgical curettage is necessary. In radiotherapy a dose of 600 rad is usually adequate; the role of radiotherapy as opposed to treatment with surgical measures should be further investigated. For disseminated forms chemotherapy is the treatment of choice. Immunotherapy with thymic extract may be an alternative but must be studied further in the future. The response to specific therapy may be slow; modification or discontinuation depends on host tolerance and toxicity. Prospective controlled trials considering the natural history of the disease, immunological aspects and risk criteria are warranted.

Identification of the immunogenically active components of the Sm and RNP antigens.

The spectrum of cellular targets in the autoimmune diseases is both large and varied and includes among the nuclear components the so-called Sm and RNP antigens associated with systemic lupus erythematosus. The use of immunoaffinity chromatography with dual specificity for the Sm and RNP antigens has allowed for their substantial purification from rabbit thymus in parallel and in quantity. In lieu of a functional assay, the use of a counterimmunoelectrophoresis assay provided a sensitive and rapid means of monitoring the distribution of the two antigens during purification and ensured the isolation of complexes containing the components required for antigenicity. The resulting purified complex consisted of nine polypeptides having molecular weights of approximately 9000 to 44,000 and two small RNAs of similar size. However, limited proteolysis of the isolated complex suggested that most of these polypeptides were not actually required for antigenic activity. Unlike Sm in crude thymus extracts, purified Sm was RNase sensitive. Thus, one of the major diagnostic criteria used to distinguish Sm and RNP antigens in crude extracts was shown to be invalid for purified material, suggesting that both antigens from rabbit thymus are actually ribonucleoprotein complexes.

Thymic Hormones and the Immune System

The central role of the thymus gland in the development and maintenance of the immune system is recognized. Biochemically characterized thymic extracts differentiate murine prethymic cells to functional T-lymphocytes. Thymosin fraction V differentiates prethymocytes to thymocytes, and mature thymocytes to competent T-lymphocytes. Thymopoietin and thymic humoral factor differentiate thymocytes; they have relatively little effect on prethymocytes. Serum thymic factor also affects a cell already at the thymocyte stage. The relative importance of each factor in the differentiation of T-lymphocytes remains unknown. Most likely, they act sequentially to produce a competent circulating T cell. The site of cellular differentiation in man by thymic factors is less well defined than in the murine system. It is established that thymosin fraction V, thymic humoral factor, and thymopoietin differentiate a subpopulation of isolated peripheral blood null lymphocytes (T cell rosette negative, surface immunoglobulin negative) to form T cell rosettes. In some situations, T cell function as assessed by response to allogeneic cells or plant lectins is enhanced following incubation with the factors. Peripheral blood lymphocytes isolated from subpopulations of children with primary or secondary immunodeficiency, or from adults with autoimmune disease or malignancy, have been incubated with thymosin fraction V. Enhanced T cell rosette formation has occurred in a subgroup of these patients. Notably, children with severe combined immunodeficiency and without stem cells for thymic factors to differentiate have had no increase in T cell rosette formation. The most important potential contribution of thymic factor research will be its precise application to the treatment of human disease. As our understanding of the differentiation of the human T cell approaches our understanding of the murine system, a more careful approach to the pathogenesis of human disease should be possible. Monoclonal antibodies capable of identifying human thymocyte and lymphocyte surface antigens have become available. By (1) evaluating the effect or effects of factors on normal human lymphocyte differentiation; (2) understanding the biochemical mechanism or mechanisms through which thymic factor differentiation occurs; (3) identifying specific abnormalities in individual disease entities; and (4) correlating disease pathogenesis with specific thymic factor effect, a logical approach to replacement therapy should be possible.

The effect of a thymic extract on the response to PHA of normal lymphocytes.

Evidence is presented to show that a thymic extract is capable of altering the response of peripheral blood mononuclear cells to PHA. If the initial response is poor then this is increased towards a maximal value. If the response is maximal initially, it is depressed after incubation.

Enhancement of the immune system of chemotherapy-treated cancer patients by simultaneous treatment with thymic extract, TP-1

Thirty patients with incurable gastrointestinal cancer were treated in a randomized clinical trial, either with combination chemotherapy (5-fluorouracil, vincristine, and methyl-CCNU) or with the same chemotherapy and the thymic extract TP-1. T-lymphocyte counts slowly and steadily, increased in the TP-1-treated patients over a period of 4–5 months, in contrast to decreasing counts in the patients treated by chemotherapy only. The changes in both groups were significantly different from pretreatment counts (P<0.01). Skin tests for primary sensitization with DNCB were converted to positive or improved after TP-1 treatment (P<0.05 against control patients). In conclusion, TP-1 had a progressively accumulating effect on T-cell lymphopoiesis and activity (skin tests), which was strong enough to overcome chemotherapy-induced immunosuppression without any appreciable side effects.

The detection and identification of antibodies to saline extractable nuclear antigens by counterimmunoelectrophoresis

AbstractSera containing antibodies to the saline extractable nuclear antigens RNP, Sm, and Ha can be identified with counterimmunoelectrophoresis (CIE) by matching their precipitin reactions to those of reference sera. The CIE reaction of Sm is unusual in that two preciptin lines are formed, one of which shows partial immunologic identity with the reaction to RNP. Sera were identified with the reaction to RNP. Sera were identified by CIE which reacted with additional acidic antigens in rabbit thymus extract, some of which had the same enzyme sensitivity profiles as RNP and Ha but were immunologically not identical and could not be detected by hemagglutination with red cells coated with calf thymus nuclear extract. Although the incidence of reactivity to RNP, Sm, and Ha was similar to previous reports, review of the clinical manifestations of 128 patients with systemic lupus erythematosus (SLE) did not provide statistically significant confirmation of previously to reactivity and particular patterns of disease expression. With due attention paid to technical artifacts, CIE is a sensitive and specific method for identifying sera reactive with acidic nuclear antigens that has practical advantages over alternative methods.

Thymic lymphocytes bear a surface antigen which cross-reacts with acetylcholine receptor.

Acetylcholine receptor (AChR) is a major antigen in the neuromuscular disease myasthenia gravis and it is clear today that the basic defect in this disease is brought about by an autoimmune attack on acetylcholine receptors at the neuromuscular junctions. The involvement of the thymus and its role in myasthenia have been widely investigated but are still poorly understood. A high incidence of thymic abnormalities is observed in patients with myasthenia and thymectomy is beneficial in many cases. Immunological studies have demonstrated the presence of humoral as well as cellular immune responses towards thymic tissues in myasthenic patients. There were also some reports that animals immunized with thymic extracts develop a partial defect in neuromuscular transmission. In spite of all these observations, the nature and origin of the association between the thymus and the neuromuscular junction in myasthenia gravis are still not known. We have previously demonstrated an immunological cross-reactivity, both humoral and cellular, between a thymic component and AChR; such a cross-reactivity could provide a molecular explanation for the involvement of the thymus in myasthenia gravis. In this study, we demonstrate, by using immunofluorescence and radioimmunological techniques, that thymic lymphocytes bear a surface antigen which binds specifically to antibodies against nicotinic AChR and is thus defined as an 'AChR-like' antigen. A preliminary report of this study has been published.

Heterogeneity of precipitating antibodies in polymyositis and dermatomyositis. Characterization of the Jo-1 antibody system.

Precipitating antibodies occurring in 26 "pure" polymyositis (PM) patients and 22 "pure" dermatomyositis (DM) patients were studied by double immunodiffusion using calf thymus nuclear extract and whole calf thymus extract. Seventeen of 26 (65%) PM sera and 13 of 22 (59%) DM sera showed positive reactions, and 18, 10, and 2 sera exhibited 1, 2, and 3 precipitin lines, respectively. Common specificities were established by immunodiffusion for the 11 PM and 6 DM sera with strong precipitin lines. These were classed into three groups of shared specificity and six reactions specific for individual sera. These 9 calf thymus antigens were shown to be different from the known soluble tissue antigens Sm, nuclear RNP, Ro, and La. A 600-fold purification of the most frequently appearing system designated Jo-1 was achieved and its clinical specificity for patients with PM syndromes was established.

Immunorestoration of old mice by injection of thymus extract: Enhancement of T cell-T cell cooperation in the in vitro antibody response

The effect of injecting a thymus extract (TP-1 or Thy-5) into immunodeficient old mice on the in vitro antibody response of their spleen cells was investigated by techniques suitable for dissecting out T- and B-cell reactivities. The anti-TNP antibody response of HRBC-primed spleen cells from old mice uninjected or injected with TP-1 or Thy-5 was elicited in vitro by TNP-HRBC or TNP-Ficoll. Treatment with TP-1 or Thy-5 was found to induce only a slight increase in the anti-TNP antibody response to both immunogens. The helper activity of HRBC-primed spleen cells from untreated or treated old mice was titrated by adding graded numbers of these primed cells to cultures containing a constant number of normal spleen cells from young mice and the immunogen TNP-HRBC. Under these conditions it was found that both thymus extracts are very effective in restoring T cell-T cell cooperation in the generation of helper cell activity.

Critical reexamination of the thymus immunization model of myasthenia gravis.

Previous studies have described an experimental model of myasthenia gravis (MG) produced by immunizing animals with thymus extracts. In view of the hypothesis that the autoimmune process in MG may be initiated within the thymus itself, we have reexamined this model using presently available methods to evaluate its resemblance to MG. We immunized Lewis rats with extracts of rat thymus in Freund's adjuvant, as originally described by G. Goldstein. Five procedures were used to test for myasthenic characteristics: (1) repetitive nerve stimulation; (2) recording of miniature endplate potentials; (3) assays of anti-ACh receptor antibodies in serum; (4) determination of ACh receptors at neuromuscular junctions by [125I] alpha-bungarotoxin binding; and (5) evaluation of the histology of the thymus gland. Our results showed that the thymus-immunized animals did not demonstrate abnormalities in any of these parameters. We conclude that immunization of rats with thymus extracts, as described, failed to produce a myasthenia-like condition.

Immunotherapy of patients with chronic virus B hepatitis: I. Maturation of human T-lymphocytes under influence of calf thymic hormone

Well known thymic-dependent properties of T-lymphocytes, E-rosetting, and phytomitogenic responsiveness, were observed to be lowered in some patients with chronic virus-B hepatitis. On the assumption that these deficiencies may be due to lack of thymic influence, we decided to attempt their repair by administration of the thymus extract “TFX-Polfa” to the patients. The earliest effect of treatment observed was an increase in percentage of E-rosetting cells to a value within the normal range. Prolonged treatment resulted in the increase of lymphocyte response to stimulation with concanavalin A, and thereafter in significant increase in reactivity to phytohemagglutinin. It is suggested that these quantitative and qualitative improvements elicited by TFX in the peripheral blood lymphocyte pictures of the patients arise out of its ability to induce in vivo sequential processes of differentiation of thymus-dependent lymphocytes normally accomplished by the thymus.