摘要:

SummaryOptimal conditions were established for specific labelling of the surface proteins of mouse erythrocytes using lactoperoxidase‐catalyzed radioiodination. The levels of H2O2and I‐, and cell concentrations required for restriction of haemoglobin labelling to less than 5% of the total125I‐protein, were different for radioiodination employing direct H2O2addition or generation of H2O2with glucose oxidase plus glucose. Preparation of mouse erythrocyte ghosts by hypotonic lysis caused loss of some minor labelled proteins present on intact cells and shifts to lower molecular weights of others. It is therefore important to solubilize labelled cells directly in electrophoresis buffer to avoid artifactual degradation of labelled proteins. The extent of labelling internal cell proteins was measured by a procedure suitable for the comparison of a large number of samples: solubilized radioiodinated erythrocytes were electrophoresed on 14% acrylamide gels and the radioactivity determined in the haemoglobin band which migrates separately from other proteins. The major labelled protein on the mouse erythrocytes bad an apparent molecular weight of 92,000, and may be analogous to Band 3 of the human erythrocyte.

ISSN:0004-945X    

DOI:10.1038/icb.1979.37

出版商:Nature Publishing Group    

年代:1979

数据来源: WILEY

摘要:

SummaryMice chronically infected with 3 metazoan and 1 protozoan parasite contain in their circulation levels of IgG1which are increased over the levels in uninfected mice by at least 10×. In the case of infection with the larval cestode,Mesocestoides corti. the serum IgG1concentration can reach>50 mg/ml and, with a half‐life of<2 days, the number of cells engaged in IgG1production is approximately 2 × 108. The IgG1hypergammaglobulinaemia is not seen in infected hypothymic nude mice. Biosynthetic labelling studies with organ and tissue cultures established that in two of the chronic infections the organs principally involved in IgG1synthesis were those pathologically involved or those “in line” for antigen capture: i.e. liver and spleen in the case of M. corti which is located in the liver and the peritoneal cavity, and various intestinal lymph nodes in the case of the gut‐dwelling nematode,Nematospiroides dubius. This apparently exaggerated response to chronic parasitic infection is of interest simply because of the potential magnitude of the effect and the fact that it involves an Ig isotype with very poorly defined biological function.

ISSN:0004-945X    

DOI:10.1038/icb.1979.38

出版商:Nature Publishing Group    

年代:1979

数据来源: WILEY

摘要:

SummaryTbe IgG1molecules in the sera of IgG1hypergammaglobulinaemic mice chronically infected with the larval cestode,Mesocestoides corti, are a heterogeneous population. Although antibodies toM. cortiare present, the question of whether a minority or majority of the serum IgG1molecules has anti‐parasite reactivity remains open. The splenic PFC response to an intravenous injection of SRBC inM. corti‐infected mice does not consist of an unusually high proportion of IgG1anti‐SRBC PFC. Moreover, the adoptive anti‐DNP PFC response of spleen cells from M. corti‐infected mice to DNP‐M. cortiis not biased towards IgG1antibody production.Since IgG1hypergammaglobulinaemia is seen in mice with chronic, “high‐dose” infections, an attempt has been made to simulate chronic antigenic exposure with SRBC in uninfected mice. A split, high‐dose regime of SRBC injections leads to a high number and high proportion of IgG1anti‐SRBG PFC in the spleen in three strains of mice. The results suggest that the extraordinarily high levels of IgC1seen in the sera of mice chronically infected with the metazoan,M. cortiandNematospiroides dubius, reflect persistent, high‐dose, “strong”. T cell‐dependent stimulation of the B cell system.

ISSN:0004-945X    

DOI:10.1038/icb.1979.39

出版商:Nature Publishing Group    

年代:1979

数据来源: WILEY

摘要:

SummaryRadioactive human serum albumin (125I‐HSA) was injected into the hind foot pads of unimmunized mice, actively immunized mice and mice passively immunized with mouse or rabbit anti‐HSA serum. Eleven days later the unimmunized mice had cleared most of the125I‐HSA. In contrast, a high concentration of125I‐USA was retained in the feet and draining lymph nodes and, to a lesser extent, in the spleen of the actively or passively unimmunized mice. Although immune retention required specific antibody, it appeared to be independent of T‐cells or T‐cell factors, since passively immunized nude mice retained antigen as well as actively or passively immunized normal mice. Depletion of the complement system with cobra venom factor (CVF) increased antigen retention in the feet but decreased retention in the spleen. Treatment with CVF did not decrease antigen retention in lymph nodes of actively immunized mice. Such treatment did, however, decrease retention in lymph nodes of passively immunized mice although not to the same extent as in the spleen. Retention of antigen in the feet was not only complement‐independent but was also Fc independent, since F(ab′)2fragments of IgG could mediate immune retention. Antigen dose response studies indicated that immune retention in lymph nodes occurred optimally with minute amounts of antigen, whereas optimal retention in the feet required much higher concentrations of antigen. Foot pad injections of non‐radiolabelled USA eliminated 60% of the radioactivity retained in the foot pads of unimmunized mice. In contrast, non‐radioactive egg albumin (EA) had almost no effect on retained HSA. However, if the mice were immunized to both EA and HSA, an injection of EA would displace a significant amount of retained HSA. Complexes of one specificity can apparently displace some retained antigen of a differing specificity.

ISSN:0004-945X    

DOI:10.1038/icb.1979.40

出版商:Nature Publishing Group    

年代:1979

数据来源: WILEY

摘要:

SummaryFive previously reported New Zealand bovine enteroviruses are further characterised with regard to their biophysical and serological properties. Characteristics studied included heat stability, buoyant density, virus replication, plaque production and thin section electron microscopy. Serological tests indicated the isolates belonged to two different serogroups which showed only limited relationships with U.S. serotypes BES 1, 3 and 4. A correlation was noted between 2(α‐hydroxybenzyl) benzimidazole sensitivity, heat stability and the serogroup of the isolates.

ISSN:0004-945X    

DOI:10.1038/icb.1979.41

出版商:Nature Publishing Group    

年代:1979

数据来源: WILEY

摘要:

SummaryLymphocytes cytotoxic for mouse embryo fibroblasts (MEF) infected with murine cytomegalovirus (MCMV) were produced by in vitro culture of “memory” spleen cells with UV‐irradiated, MCMV‐infected, MEF. Cytotoxic lymphocytes were developed from spleen cells of mice 10 to 240 days after infection with MCMV, The cytotoxic cells carried the theta and Ly 2 antigens, and were H‐2 restricted in the recognition of infected target cells.

ISSN:0004-945X    

DOI:10.1038/icb.1979.42

出版商:Nature Publishing Group    

年代:1979

数据来源: WILEY

摘要:

SummaryA double immunofluorescence staining technique to locate concanavalin A (Con A) surface receptors and cytoplasmic actin in the same cell was applied to monolayer cultures of rat foetal fibroblasts during cell detachment induced by trypsin and during cell attachment to a glass substratum. Con A receptors were demonstrated by fluorescein‐isothiocyanate‐labelled Con A (FITC‐Con A) and actin by specific anti‐actin antibody (AAA) traced with rhodamine‐labelled goat anti‐human globulin (R‐AHG). Untreated, control cells had an elongated shape. Con A receptors restricted to cell margins and prominent actin filaments. After 2 min treatment with 0·001% trypsin the cells became angular with Con A receptors in clusters and actin in a diffuse or aggregate staining pattern. Progressive cell rounding followed and this was accompanied by the development of long, thin, arborized cell processes, studded with Con A receptors and containing fine actin filaments. Complete cell rounding preceded cell detachment. The sites of detached cells were marked by fine aggregates containing Con A receptors and actin.In cells attaching to a glass substratum, actin was present in a diffusely stained or aggregate pattern in round cells, in filaments restricted to cell margins in partially spread cells and in numerous filaments in fully spread cells. Con A receptors were present in clusters in round cells, in clusters or caps in partially spread cells and in cell margins in fully spread cells. Binding of FITC‐Con A to partially spread cells resulted in dissolution of the few, newly formed, actin filaments.We believe our observations are consistent with the idea that actin filaments, formed during cell attachment, contribute towards the maintenance of cell adhesion by helping in the preservation of cell shape and by anchorage of Con A receptors at points of cell attachment to the substratum.

ISSN:0004-945X    

DOI:10.1038/icb.1979.43

出版商:Nature Publishing Group    

年代:1979

数据来源: WILEY

ISSN:0004-945X    

DOI:10.1038/icb.1979.44

出版商:Nature Publishing Group    

年代:1979

数据来源: WILEY