RESUMO
We studied the effects of tactivin and splenic polypeptides on learning and memory of thymectomized animals. In 3-week rats, thymectomy blocked active avoidance conditioning. Injections of tactivin (0.5 mg/kg) during 1 month after surgery restored learning capacity; splenic polypeptides were ineffective.
Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Memória/efeitos dos fármacos , Nootrópicos/farmacologia , Peptídeos/farmacologia , Timectomia , Extratos do Timo/farmacologia , Timo/química , Animais , Aprendizagem da Esquiva/fisiologia , Condicionamento Clássico/fisiologia , Memória/fisiologia , Nootrópicos/isolamento & purificação , Especificidade de Órgãos , Peptídeos/isolamento & purificação , Ratos , Ratos Wistar , Baço/química , Extratos do Timo/isolamento & purificação , Timo/fisiologia , Timo/cirurgiaRESUMO
High-performance liquid chromatography (HPLC) was used to evaluate the purity and batch-to-batch consistency of four commercially available thymic extracts and thymopentin, the synthetic pentapeptide corresponding to the biologically active region of the thymic hormone thymopoietin. The thymus extracts were all extremely heterogeneous, differing one from the other. Additionally, they showed high batch-to-batch variation. In contrast, thymopentin was homogeneous and this homogeneity was consistent in different batches.
Assuntos
Fragmentos de Peptídeos/análise , Timopoietinas/análise , Extratos do Timo/isolamento & purificação , Hormônios do Timo/análise , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , Hormônios/análise , Fator Tímico Circulante/isolamento & purificação , Timopentina , Timopoietinas/isolamento & purificação , Timosina/isolamento & purificaçãoRESUMO
The expression of antigen Thy-1 was studied in bone marrow cells of CBA line mice under the effect of thymus extracts. Extracts of the calf thymus--thymosine (fraction 5) and the preparation free of the Comsa factor were obtained by a combination of the Goldstein and Comsa extraction methods. The both extracts stimulate the expression of antigen Thy-1 in bone marrow cells. Incorporation of [14 C]sodium acetate into fragments containing antigen Thy-1 and absorbed by the column with anti-Thy-1-antibodies remains unchanged after stimulation. It is supposed that antigen Thy-1 ability to stimulate expression in bone marrow precursors of T-cells is not due to the synthesis of the antigen and is a property of one of the thymus factors with molecular mass of about 5000.
Assuntos
Antígenos de Superfície/imunologia , Medula Óssea/imunologia , Timosina/imunologia , Extratos do Timo/imunologia , Hormônios do Timo/imunologia , Animais , Bovinos , Células Cultivadas , Testes Imunológicos de Citotoxicidade , Camundongos , Camundongos Endogâmicos CBA , Coelhos , Antígenos Thy-1 , Extratos do Timo/isolamento & purificaçãoRESUMO
A thymic extract (TE) was prepared from supernatant of mice thymic epithelial cultures according to the purification of thymosin. TE and thymosin stimulated, in vitro, the immune response of mouse against deep red blood cells.
Assuntos
Formação de Anticorpos/efeitos dos fármacos , Timosina/farmacologia , Extratos do Timo/farmacologia , Hormônios do Timo/farmacologia , Animais , Eritrócitos/imunologia , Técnica de Placa Hemolítica , Masculino , Camundongos , Ovinos/imunologia , Timosina/isolamento & purificação , Extratos do Timo/isolamento & purificaçãoRESUMO
The results presented here point to the possibility that calf thymus extracts contain, in addition to the thymic hormone (THF), a second component: thymic plasma recirculating factor (TPRF). THF, which is involved in the process of T cell maturation and has been characterized as a protein of m.w. 3000 eluted in the void volume of a G-10 Sephadex column (G-10-I), caused an increased level of intracellular cAMP in umbilical cord blood lymphocytes (UCBL). This is in agreement with our previous observation that THF plays a major role in the differentiation of T cells. The second active material, TPRF, also isolated from thymic extract, is of a molecular size below 500 and was eluted in a G-10 Sephadex column at the fourth protein peak; it seems to circulate in the blood. Previously, we had observed in impaired response of UCBL to PHA and Con A stimulation in the presence of dialyzed human plasma (DHP). Our present results indicate that this impaired response is restored exclusively by TPRF. A factor with TPRF-like activity was also isolated from the plasma of normal donors; yet it was not detected in the plasma of thymectomized patients suffering from myasthenia gravis (MG). This suggests that TPRF from plasma is thymus dependent. TPRF does not affect the level of intracellular cAMP in UCBL.
Assuntos
Concanavalina A/farmacologia , Sangue Fetal/imunologia , Ativação Linfocitária , Fito-Hemaglutininas/farmacologia , Hormônios do Timo/farmacologia , AMP Cíclico/metabolismo , Diálise , Feminino , Humanos , Extratos do Timo/isolamento & purificação , Extratos do Timo/farmacologiaRESUMO
A factor that decreases rosette formation between guinea pig T-cells and rabbit red blood cells (RRBC) was extracted from the thymus of the guinea pig. The active factor could be extracted from the spleen as well as the thymus, but not from the liver or kidney. The active factor of the thymic extract was found in the precipitates produced by 80% saturated ammonium sulfate and it was separated from the water-soluble fraction of the precipitates. The molecular weight of the partially purified substance was estimated to range between 10,000 and 30,000 by filtration through a diaflow membrane. From the studies on physicochemical characterization, it might be a heat-resistant basic peptide probably bound to a ribonucleotide moiety. This factor reduced rosette formation between RRBC and guinea pig T-cells, but did not reduce erythrocyte-antibody-complement rosette formation. This factor also inhibited mitogen (concanavalin A, phytohemagglutinin-P)- induced DNA synthesis of guinea pig lymphocytes and antigen-induced DNA synthesis of sensitized guinea pig lymphocytes.
Assuntos
Formação de Roseta , Extratos do Timo/isolamento & purificação , Animais , Linfócitos B/imunologia , Sobrevivência Celular , Fenômenos Químicos , Precipitação Química , Química , Concanavalina A/farmacologia , DNA/biossíntese , Desoxirribonucleases/farmacologia , Feminino , Filtração , Cobaias , Temperatura Alta , Linfonodos/imunologia , Peptídeo Hidrolases/farmacologia , Fito-Hemaglutininas/farmacologia , Coelhos , Linfócitos T/imunologiaAssuntos
Tecido Linfoide/imunologia , Extratos do Timo/isolamento & purificação , Aminoácidos/análise , Animais , Bovinos , Cromatografia em Gel , Diálise , Reação Enxerto-Hospedeiro , Imunidade Celular , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Peso Molecular , Peptídeos/isolamento & purificação , Baço/imunologia , Extratos do Timo/análise , Extratos do Timo/imunologia , UltracentrifugaçãoRESUMO
We have shown previously that THF induces immunocompetence in lymphoid cells through the control of cellular cAMP levels and DNA synthesis. By the use of a one-way MLC assay it was now shown that the exposure of spleen cells to THF is accompanied by an increase, in the proliferative response of the responding cells. These effects are mediated by regulation of cellular levels of cAMP during the course of the MLC response. Thus, substances which modify cellular levels of cAMP such as DBcAMP, theophylline, and imidazole change the reactivity of cells exposed to THF in the MLC assay. It was also found here that cellular cAMP levels are critical in controlling the reactivity of normal spleen cells in the absence of THF. It is suggested that THF increases the number of competent cells in the spleen cell population capable of responding to antigenic stimulation in the MLC assay.
Assuntos
AMP Cíclico/biossíntese , Imunidade Celular , Baço/imunologia , Extratos do Timo , Animais , Reações Antígeno-Anticorpo , Bucladesina/metabolismo , Separação Celular , DNA/metabolismo , Imidazóis/metabolismo , Teste de Cultura Mista de Linfócitos , Masculino , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Mitomicinas/metabolismo , Baço/metabolismo , Teofilina/metabolismo , Timidina/metabolismo , Extratos do Timo/isolamento & purificação , TrítioRESUMO
Two kinds of active protein fraction, TP1 and TP2, were isolated from bovine thymus extracts. Both these fractions showed a single band in polyacrylamide gel disc electrophoresis. Though these two fractions showed a difference in potency, they both lowered serum calcium in rabbits and increased lymphocytes in mice. Molecular weight determination by SDS polyacrylamide gel electrophoresis gave the values of 68,000 for TP1 and 57,000 for TP2. Amino acid composition of TP1 did not show marked characteristics but was clearly different from that of bovine serum albumin. Isoelectric focusing showed the isoelectric point at pH 5.65 for TP1 and pH 5.4 for TP2. Dose-response relation in serum calcium-lowering activity was examined with a sample purified from the extracts, and a linear dependence of the response to log dose was recognized over a moderate range of doses. The time-course measurement of the hypocalcemic activity showed that the action of TP1 is somewhat different from that of calcitonin.