摘要:

SummaryThe influence of variations in protocol on the induction and early stages of maintenance of allograft tolerance in neonatal rats was studied. Allogeneic bone marrow cells, the anti‐recipient activity of which was specifically reduced because of their origin from immunologically tolerant donors, possessed diminished tolerogenic capacity. This was commonly manifested by development of an unreactive state in only one of the two parameters of reactivity‐allograft rejection and graft‐versus‐host reactivity‐that were monitored. A similar deviation from the occurrence of unreactivity in both forms that characterizes tolerant rats was observed in animals which had been inoculated with syngeneic thymus cells at the time of induction of tolerance. Attempts to demonstrate a requirement for an extended period of exposure of young rats to semi‐allogeneic bone marrow cells before specific unreactivity on the part of host cells became irreversible were unsuccessful.

ISSN:0004-945X    

DOI:10.1038/icb.1986.1

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryA technique for assessing the number, distribution and volume of the lymphoid aggregates (LA) in the guinea pig large bowel is described. Aggregates could be visualised macroscopically after immersion of the bowel in 10% acetic acid and their number and distribution recorded by tracing on plastic sheets. Serial sections through a sample of 13 LA showed that they were ellipsoidal and this was confirmed by mathematical comparison with hypothetical ellipsoids. In practice, only the length and width of each LA could be measured but, using the sample of 13 LA, it was established that regression analysis enabled the volumes of all except the smallest LA to be predicted accurately from the knowledge of length and width alone.

ISSN:0004-945X    

DOI:10.1038/icb.1986.2

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryPrior treatment (priming) with a weakly immunogenic dose of Type III pneumococcal polysaccharide (SIII) results in the development of an antigen‐specific state of unresponsiveness termed low‐dose paralysis which is believed to be mediated by suppressor T cells. The present findings show that the passive administration of functionally distinct non‐complement‐fixing (NCF) IgM anti‐SIII antibodies either in monoclonal form or from protein‐A absorbed immune serum could significantly suppress the direct plaque‐forming cell (PFC) response to an immunogenic dose of SIII administered concurrently. The degree of suppression was comparable with that induced by low–dose paralysis. Low‐dose paralysis was consistently induced in athymic (nude) mice 4 days, but not 3 days, after priming with a low dose of SIII, and was associated with the delayed appearance of NCF‐IgM anti‐SIII in the serum of athymic mice. In contrast, low‐dose paralysis was readily induced in normal BALB/c mice 3 days after priming when NCF‐IgM anti‐SIII antibodies were present. Comparable inhibiton of the direct anti‐SIII PFC response was observed when Concanavalin A (Con A) or NCF‐IgM anti‐SIII serum was administered with SIII antigen. That Con A and NCF‐IgM anti‐SIII together did not produce additive suppression was attributed to the adsorption of NCF‐IgM anti‐SIII antibodies to Con A. Complement‐dependent single radial haemolysis mediated by CF hybrid IgM/A or CF‐IgM anti‐SIII serum was blocked by monoclonal NCF‐IgM or IgA anti‐SIII antibodies and indicated that each of the antibodies was specific for the same SIII‐determinant. Evidence is presented to show that low‐dose paralysis in the CF‐IgM response to SIII is not mediated by suppressor T cells but can be attributed to highly avid NCF‐IgM anti‐SIII antibodies, formed preferentially to low doses of SIII, being able to reduce the immunogenicity of SIII administered subsequently.We propose that low‐dose paralysis to SIII is the result of an immunobiological function of highly avid NCF‐IgM anti‐SIII antibodies which not only confer resistance against capsulated pneumococci but preferentially bind soluble SIII‐antigen to reduce its immunogenicity and thereby protect specific CF‐IgM positive B cells from being rendered tolerant by direct contact with higher doses of SIII antigen.

ISSN:0004-945X    

DOI:10.1038/icb.1986.3

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryThyroid and thymus tissue autografts were used to examine the suitability of different transplant sites in the pig for endocrine tissue transplantation. The omental pouch, gall bladder fossa and renal subcapsular space showed optimal implantation, preservation and vascularisation of graft tissue. Marked dissemination of graft tissue was observed at intramuscular sites and graft viability at subcutaneous sites in the ear was poor. The omental pouch represents a potentially suitable site for pancreatic islet tissue transplantation studies in the pig.

ISSN:0004-945X    

DOI:10.1038/icb.1986.4

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryIt has been shown that the interaction ofDirofilaria immitismicrofilariae (Mf) opsonized with sera from infected but amicrofilaraemic dogs (occult dogs) stimulated the respiratory burst and degranulation of neutrophils as measured by chemiluminescence and iodination. Sera from normal and microfilaraemic dogs gave either low level or non‐significant reactions. Since the sera required were also those required for neutrophil–mediated cytotoxicity toD. immitisMfin vitro, the results suggested that the products of oxygen reduction as well as the myeloperoxidase system could be involved in the killing of Mf by neutrophils. However, whether these pathways have a major role to play in neutrophil–mediated cytotoxicity to Mf is uncertain, as various chemical and enzymatic inhibitors of the products of the respiratory burst were unable to prevent or reduce cytotoxicity. Azide, which is a known inhibitor of the iodination reaction, also failed to reduce cytotoxicity.

ISSN:0004-945X    

DOI:10.1038/icb.1986.5

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryLactate dehydrogenase, E.C.1.1.1.27 (LDH) from the simian malarial parasite,Plasmodium knowlesi, and from normal rhesus monkey erythrocytes has been purified using Blue Sepharose affinity chromatography, and the properties of the purified enzyme from these two sources have been compared.The enzyme from the host and parasite were different in their kinetic properties, viz., substrate and pH optima, thermostability and isoenzymic behaviour. Partially purified LDH of the erythrocytes resolved into three isomeric bands on polyacrylamide gel electrophoresis, whereas the parasite LDH moved as a single enzyme band of different mobility from the host LDH. The molecular mass of the parasite enzyme was estimated as 117,500 daltons.

ISSN:0004-945X    

DOI:10.1038/icb.1986.6

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryThe role of macrophages in immunosuppression which develops duringPlasmodium bergheiinfection in mice has been studied. The transfer of activated macrophages (or their extracts) from the infected mice with low parasitaemia (<10%) to uninfected mice enhanced their humoral response to sheep red blood cells (SRBC) as indicated by the number of splenic IgM and IgG plaque–forming cells (PFC). In contrast, when macrophages obtained during higher parasitaemia (16%) were used, significant inhibition was observed. These findings indicate that duringPlasmodium bergheiinfection in mice macrophages may play a dual role.

ISSN:0004-945X    

DOI:10.1038/icb.1986.7

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryWe analysed the breathing patter n of anaesthetised rabbits during unloaded breathing when breathing was accelerated by inspired CO2and when they breathed against positive or negative pressures before and during block of pulmonary stretch receptors by SO2, and after bilateral vagotomy. Before block moderate steps of inflation or deflation (0·5 kPa) produced relatively larger changes in duration of expiration than in duration of inspiration, indicating the relative sensitivities of the two phases. With stretch receptors, blocked inflation or deflation shortened expiration, demonstrating the influence of rapidly adapting receptors on that phase of breathing. If pulmonary stretch receptors were the major determinants of the duration of inspiration, we would have expected inspiratory duration in the stretch receptor blocked and vagotomised states to be almost identical. They were not, inspiratory duration being less in the blocked than in the vagotomised state. Possibly vagal afferent activity other than that of stretch receptors shortens inspiratory duration. However, we have found that rapidly adapting receptor activity (and any unmyelinated fibre activity provoked by rapid inflation or deflation of the lungs) never directly shortened inspiration. We therefore propose a mechanism whereby rapidly adapting receptors may indirectly affect duration of inspiration.

ISSN:0004-945X    

DOI:10.1038/icb.1986.8

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryThe effect of administration of carnitine on the severity of myocardial infarction in rats induced by isoproterenol was studied by following histopathological and biochemical parameters. Carnitine afforded partial protection against myocardial infarction. Serum aspartate amino transferase (GOT) and creative phospho kinase (CPK) values, serum, heart and aortic lipids, serum protein‐bound hexose and sialic acid and glyco‐saminoglycans in the heart were lower in the carnitine‐treated rats. Histopathological examination showed very little necrosis in the carnitine‐treated rats when compared to the extensive necrosis in the untreated controls.

ISSN:0004-945X    

DOI:10.1038/icb.1986.9

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryFemale guinea pigs, inoculated intravaginally with a herpes simplex virus‐type 2 (HSV‐2) strain M1, developed typical symptoms of a primary and recurrent genital herpes infection. Sera from HSV‐2 infected guinea pigs taken during the primary or recurrent stages of the genital infection contained complement (C)‐fixing antibody which reacted with an apparent type specificity to an early 4 h HSV‐2 infected cell extract (AG‐4) when compared to a 4 h HSV‐1 infected cell extract. This C‐fixing anti‐AG‐4 activity was shown to be associated with the IgG2 subclass and directed primarily against HSV‐2 infected cell polypeptide (ICP)6 and ICP8. Furthermore, C‐fixing anti‐AG‐4 levels remained constant after the primary infection and during recurrences for over 6 months. Thus, while the anti‐AG‐4 response in guinea pigs was of the IgG type, it varied from that found previously in human genital HSV‐2 sufferers which was of the IgM type. Also, while an IgG anti‐AG‐4 response in human genital HSV‐2 sufferers is associated with a reduction in the number of recurrences, this reduction is not apparent in the guinea pig model.

ISSN:0004-945X    

DOI:10.1038/icb.1986.10

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY