RESUMEN
The prevention of breeding in animals using GnRH analogues has been the object of research over many years. Recently, a new drug delivery formulation was developed which enabled the development of products that could be commercialised for veterinary use. The formulation has now been approved in certain countries for use in male dogs, and applications are being expanded to cover repeat usage, extended duration, use in females, other indications and other animal species. With respect to repeat usage, dogs have been re-implanted for four consecutive doses and monitored until they returned to normal steroidogenesis. All dogs returned to normal steroidogenesis following cessation of treatment. In females, it was previously shown that implanted bitches with progesterone < 5 ng/mL at the time of implantation had an induced estrus. In a new study at Chulalongkorn University, implanting female pups at around 4 mo prevented this occurrence, whereas implantation at 7 mo did not.
Asunto(s)
Anticonceptivos/farmacología , Perros/fisiología , Estro/efectos de los fármacos , Pamoato de Triptorelina/análogos & derivados , Animales , Implantes de Medicamentos , Estro/fisiología , Femenino , Masculino , Reproducción/efectos de los fármacos , Testosterona/sangre , Pamoato de Triptorelina/farmacologíaRESUMEN
Continuous low-dose administration of a GnRH analogue postpones oestrus in bitches and suppresses reproductive function in dogs. A new drug delivery formulation that could enhance the practicality of this approach for the control of reproduction has been developed. The objective of the present study was to determine whether this method of delivery could, by sustained release of the GnRH analogue deslorelin, act as a reversible anti-fertility agent in domestic male and female dogs for periods exceeding 1 year. Several long-term studies were performed, which monitored reproductive function in 30 dogs and 52 bitches. Suppression of reproductive function in male dogs was dose-related. Spermatogenesis was suppressed for more than a year in 14 of 16 dogs that received doses of > 0.25 mg deslorelin kg-1. In females, postponement of oestrus for periods of up to 27 months was observed, but there was no relationship between the stage of the oestrous cycle at the start of treatment and the duration of efficacy. Treatment-induced effects on fertility were reversible in both sexes. In summary, sustained release deslorelin implants were shown to elicit reversible long-term reproductive control in male and female domestic dogs.
Asunto(s)
Anticoncepción/veterinaria , Anticonceptivos/administración & dosificación , Perros , Hormona Liberadora de Gonadotropina/análogos & derivados , Hormona Liberadora de Gonadotropina/administración & dosificación , Animales , Anticonceptivos Femeninos/administración & dosificación , Anticonceptivos Masculinos/administración & dosificación , Relación Dosis-Respuesta a Droga , Implantes de Medicamentos , Estro/efectos de los fármacos , Femenino , Masculino , Espermatogénesis/efectos de los fármacos , Pamoato de Triptorelina/análogos & derivadosRESUMEN
The capacity of activated T cells to alter their cytokine expression profiles after migration into an effector site has not previously been defined. We addressed this issue by paired daughter analysis of a type 1-polarized CD8(+) effector T cell population freshly isolated from lung parenchyma of influenza virus-infected mice. Single T cells were activated to divide in vitro; individual daughter cells were then micromanipulated into secondary cultures with and without added IL-4 to assess their potential to express type 2 cytokine genes. The resultant subclones were analyzed for type 1 and 2 cytokine mRNAs at day 6-7. When the most activated (CD44(high)CD11a(high)) CD8(+) subpopulation from infected lung was compared with naive or resting (CD44(low)CD11a(low)) CD8(+) cells from infected lung and from normal lymph nodes (LNs), both clonogenicity and plasticity of the cytokine response were highest in the LN population and lowest in the activated lung population, correlating inversely with effector function. Multipotential cells were nevertheless detected among clonogenic CD44(high)CD11a(high) lung cells at 30-50% of the frequency in normal LNs. The data indicate that activated CD8(+) T cells can retain the ability to proliferate and express new cytokine genes in response to local stimuli after recruitment to an effector site.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Citocinas/inmunología , Activación de Linfocitos/inmunología , Animales , Células Clonales , Citocinas/genética , Femenino , Receptores de Hialuranos/inmunología , Interferón gamma/genética , Interleucina-10/inmunología , Interleucina-4/inmunología , Interleucina-4/farmacología , Pulmón/inmunología , Pulmón/virología , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/virología , Antígeno-1 Asociado a Función de Linfocito/inmunología , Ratones , Ratones Endogámicos BALB C , Infecciones por Orthomyxoviridae/inmunología , Fenotipo , ARN Mensajero/metabolismoRESUMEN
RT-PCR was used to examine the expression of IFN-gamma, IL-2, IL-4, IL-5, IL-6 and IL-10 mRNAs by single murine CD4+ T cells activated either in a strongly type 1-polarized mixed lymphocyte reaction (MLR) or in the type 2-polarized response to immunization with keyhole limpet hemocyanin (KLH) in alum. The frequencies of expression of each cytokine differed markedly between the two responses, consistent with their polarization at the population level. However, most cells expressed only none to three of the six cytokines assayed, few displayed the canonical type 1 profile and none in either response expressed a full type 2 or type 0 profile. A significant fraction of cells co-expressed IFN-gamma with IL-4 and/or other type 2 cytokines at frequencies that suggested that most of these genes were independently regulated. Collectively, these single-cell expression patterns indicate that polarization at the population level can mask substantial intercellular heterogeneity, and show directly that multiple type 1 and 2 cytokines can be expressed simultaneously in an individual T cell.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Citocinas/genética , Citocinas/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Animales , Diferenciación Celular , Hemocianinas/inmunología , Prueba de Cultivo Mixto de Linfocitos , Ratones , Ratones Endogámicos C57BL , Células TH1/inmunología , Células Th2/inmunologíaRESUMEN
By virtue of their strong bias towards production of interferon-gamma (IFN-gamma), CD8+ T cells have the potential to promote the development of type 1 immune responses. We have previously shown that the CD4+ T-cell response to immunization with the protein antigen keyhole limpet haemocyanin (KLH) has a mixed interleukin-4 (IL-4)/IFN-gamma production profile. Here we show that this immunization regimen also stimulates accumulation in the draining lymph nodes of CD8+ T cells, which preferentially contain IFN-gamma mRNA ex vivo and secrete IFN-gamma protein in vitro. This provides a model to test whether CD8+ cell-derived IFN-gamma participates in the normal control of the immune response to a non-viable exogenous antigen. To investigate regulation of the anti-KLH response by the CD8+ population or IFN-gamma produced by this or other cell types, mice were administered depleting antibodies. Depletion of CD8+ cells had no effect on the frequency of clonogenic KLH-specific CD4+ T cells, the IL-4/IFN-gamma profiles of their progeny, or the isotype profiles of the serum antibody response to KLH. In contrast, IFN-gamma neutralization diminished cell accumulation in the lymph nodes and reduced both the frequency of KLH-specific CD4+ T cells that gave rise to IFN-gamma-producing clones and serum titres of KLH-specific IgG2a and IgG3. Therefore, despite the potential for cross-regulation, the CD4+ T-cell response to this immunogen is independent of the IFN-gamma-skewed CD8+ response.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Hemocianinas/farmacología , Interferón gamma/metabolismo , Activación de Linfocitos , Animales , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos/metabolismo , Ensayo de Inmunoadsorción Enzimática , Epítopos , Femenino , Interleucina-4/metabolismo , Depleción Linfocítica , Ratones , Ratones Endogámicos C57BL , Modelos Inmunológicos , Factores de TiempoRESUMEN
The regulation of CD4 expression on macrophages and its role in immune cell interactions remain obscure. In contrast with primary lymphocytes, primary macrophages express only low amounts of surface CD4, which is regulated differentially for example by adherence in vitro. We report that addition of LPS for 1-5 days to human blood monocyte tissue culture-derived macrophages (TCDM) down-regulates both surface CD4 expression and total cellular CD4 antigen content as measured by flow cytometry and Western blot analysis. TNF-alpha and IL-1 beta, proinflammatory cytokines which are both induced by LPS, also down-regulate surface and total CD4 expression in TCDM. This down-regulation of CD4 expression by LPS, TNF-alpha, and IL-1 beta occurs at the level of transcription. The decreased macrophage CD4 expression induced by LPS was blocked by MoAbs directed against human TNF-alpha and IL-1 beta, demonstrating that LPS acts on CD4 expression through induction of endogenous TNF-alpha and IL-1 beta. Conversely, neither LPS nor TNF-alpha and IL-1 beta were able to modulate surface CD4 expression on quiescent or phytohaemagglutinin (PHA)-activated lymphocytes. Of other cytokines and growth factors tested, Th2 cytokines (IL-4, IL-10, IL-13), chemokines (MCP-1, MIP-1 alpha, RANTES), and macrophage colony-stimulating factor did not alter CD4 expression in primary macrophages; granulocyte-monocyte colony-stimulating factor and the prototypal Th1 cytokine interferon-gamma (IFN-gamma) modulated surface CD4 expression only after prolonged treatment (5 days). Our results show that LPS, TNF-alpha and IL-1 beta selectively down-regulate CD4 expression in primary human macrophages, and that decreased CD4 expression induced by LPS results from endogenous secretion of TNF-alpha and IL-1 beta by the macrophages.
Asunto(s)
Adyuvantes Inmunológicos/farmacología , Antígenos CD4/metabolismo , Endotoxinas/farmacología , Mediadores de Inflamación/farmacología , Interleucina-1/farmacología , Lipopolisacáridos/farmacología , Macrófagos/metabolismo , Factor de Necrosis Tumoral alfa/farmacología , Células Cultivadas , Citocinas/farmacología , Regulación hacia Abajo , HumanosRESUMEN
Regulation of macrophage scavenger receptor (MSR) activity may be an important determinant of the extent of atherogenesis. The effect of macrophage-colony-stimulating factor (M-CSF) on this pathway was studied using a recently developed monoclonal antibody to murine MSR. M-CSF markedly and selectively increased MSR synthesis in murine macrophages: posttranslationally, the receptor appeared more stable and shifted to a predominantly surface distribution. Functionally, M-CSF enhanced modified lipoprotein uptake and increased divalent cation-independent adhesion in vitro. These results suggest a plausible mechanism whereby M-CSF production in the atheromatous plaque microenvironment could promote the recruitment and retention of mononuclear phagocytes and subsequent foam cell formation.
Asunto(s)
Factor Estimulante de Colonias de Macrófagos/fisiología , Receptores Inmunológicos/fisiología , Animales , Anticuerpos Monoclonales/inmunología , Secuencia de Bases , ADN , Humanos , Ratones , Ratones Endogámicos BALB C , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Procesamiento Proteico-Postraduccional , Receptores DepuradoresRESUMEN
Interleukin (IL)-13 is a newly described cytokine expressed by activated lymphocytes. We examined the effects of the murine recombinant cytokine on the phenotype and activation status of elicited peritoneal macrophages (M phi), concentrating on activities which are known to be modulated by interferon-gamma and IL-4. IL-13 markedly suppressed nitric oxide release and to a lesser extent secretion of the pro-inflammatory cytokine tumor necrosis factor-alpha. However, antimicrobial capacity was not completely jeopardized as the respiratory burst was unaffected, and indeed the enhanced expression of M phi mannose receptor and major histocompatibility class II, and regulation of sialoadhesin, the M phi sialic acid-specific receptor involved in hemopoietic and lymphoid interactions, suggest that these cells are not simply deactivated, but primed for an active role in immune and inflammatory responses. These activities closely mimic those of IL-4, but mediation of the effects by IL-4 was discounted by the use of a neutralizing monoclonal antibody. Thus, IL-13, like IL-4, is a cytokine which has complex effects on M phi behavior, inducing activities characteristic of both activation and deactivation.
Asunto(s)
Interleucinas/farmacología , Lectinas Tipo C , Activación de Macrófagos/efectos de los fármacos , Lectinas de Unión a Manosa , Glicoproteínas de Membrana , Animales , Western Blotting , Células Cultivadas , Interferón gamma/farmacología , Interleucina-13 , Interleucina-4/farmacología , Macrófagos Peritoneales/efectos de los fármacos , Masculino , Receptor de Manosa , Ratones , Ratones Endogámicos BALB C , Óxido Nítrico/biosíntesis , Receptores de Superficie Celular/efectos de los fármacos , Receptores Inmunológicos/biosíntesis , Lectina 1 Similar a Ig de Unión al Ácido Siálico , Superóxidos/metabolismo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
The mechanisms by which cellular immunity maintains the asymptomatic state after human immunodeficiency virus type 1 (HIV-1) infection are poorly understood. CD4+ T lymphocytes play a complex role in regulating anti-HIV effector pathways, including activation of macrophages, which are themselves implicated in clinical latency and pathogenesis of symptomatic acquired immune deficiency syndrome. We have found that a newly identified T helper type 2 lymphokine, interleukin 13 (IL-13), inhibits HIV-1ADA and Ba-L replication in primary tissue culture-derived macrophages but not in peripheral blood lymphocytes. Viral production in cells was measured by viral protein (p24) and reverse transcriptase levels, while entry was assessed by proviral DNA analysis at timed intervals after infection. Inhibition by IL-13 was dose and time dependent and not mediated through altered viral entry, reverse transcription, or viral release. IL-13 is therefore a candidate cytokine for the suppression of HIV infection within monocytes and macrophages in vivo.
Asunto(s)
VIH-1/efectos de los fármacos , Interleucinas/farmacología , Macrófagos/microbiología , Secuencia de Bases , Células Cultivadas , ADN de Cadena Simple , VIH-1/fisiología , Humanos , Interleucina-13 , Datos de Secuencia Molecular , Proteínas Recombinantes/farmacología , Linfocitos T/microbiología , Replicación Viral/efectos de los fármacosRESUMEN
Brucella abortus injected into CBA mice replicated primarily in the spleen and liver, reaching a peak bacterial count in both organs about 7 days postinfection. The organism was eliminated from the liver but declined to a chronic phase in the spleen. The infection caused hepatosplenomegaly. An influx of macrophages into the two organs was monitored by quantitative Northern (RNA blot) analysis of the macrophage-specific marker lysozyme mRNA. Lysozyme mRNA was detectable in spleen and increased three- to fourfold during infection. In liver, lysozyme mRNA was initially undetectable, but at about the peak of infection it reached a level comparable to that in the spleen. Macrophage colony-stimulating factor 1 (CSF-1) has been reported to be elevated in the circulation of animals infected with B. abortus and is known to stimulate monocytopoiesis. To investigate the role of CSF-1 in pathogenesis, we studied the effect of further increasing the CSF-1 concentration by administration of recombinant human CSF-1. Since the infection is characterized by several distinct phases, recombinant human CSF-1 was administered at defined times relative to these phases. Pronounced effects were observed only when CSF-1 administration was begun during the developing acute phase. The consequences were decreased bacterial numbers in the spleen but an increase in the liver, reduced antibody generation, and increased hepatosplenomegaly. A feature of many chronic intracellular infections is immunosuppression. B. abortus caused a substantial diminution of responsiveness of spleen cells to T-cell mitogens, particularly concanavalin A. This action was mimicked by CSF-1 treatment of the animals prior to spleen cell isolation. The results suggest that CSF-1 plays a role in macrophage recruitment in brucellosis and that recruited macrophages contribute to the immunopathology and immunosuppression.