Studies of the thymus in Chagas' disease: III. Colonization of the thymus and other lymphoid organs of adult and newborn mice by Trypanosoma cruzi

Among newborn and adult euthymic and athymic mice infected intraperitoneally with 10(2) or 10(4) trypomastigotes, neonates and adult athymic animals exhibited greater susceptibility with heavier colonization of central and peripheral lymphoid organs. Contiguity was also found to be a significant factor in colonization: after similar inocula, the parasitic load in the thymus was comparable in adults and neonates when the former were infected by subcutaneous injection in the anterior neck. In the nude athymic mice, the Y (reticulotropic) strain and the CL (myotropic) strain exhibited similar invasiveness, suggesting that the host immune response modulated the tissular tropism of these strains seen in the heterozygous littermates (Nu/+). The bone marrow was heavily infected; parasites were found in chondrocytes and cells of the mononucleate phagocytic system. Ultrastructural studies of infected thymus specimens showed that the corticomedullary architecture was unaltered and that both macrophages and epithelial cells were infected: both these cell types were infected in vitro.     

Uptake of intravenously administered soluble immune complexes by type I alveolar cells and macrophages in mice

Mice (C57BL/6, n = 5) were given a single intravenous injection of soluble bovine serum albumin (BSA)-rabbit anti-BSA immune-complexes (IC) prepared at five-fold antigen excess. The mice were sacrificed 15 and 30 min, and 1, 2, 4 and 12 h after injection. Granular immunofluorescence for BSA and rabbit IgG, in a pattern consistent with IC aggregation, was observed in the alveolar walls and in the cytoplasm of alveolar cells. Moderate immunofluorescence was observed 15 min after IC injection and maximal immunofluorescence was observed at 30-60 min which decreased rapidly 2 h after IC administration. Only a trace amount of immunofluorescence was observed at 4 h and none was seen at 12 h. Light microscopic immunoperoxidase staining showed localization of IC in the interstitium of the alveolar septa and in type I alveolar cells and alveolar macrophages. By immunoelectronmicroscopy, the uptake of IC in the cytoplasm of type I alveolar cells and alveolar macrophages was confirmed.     

Modulation of B cell maturation and migration to the thymus of SJL mice. B cell migration to the thymus.

The direct linkage of the B cell maturation process and infiltration of the thymus with mature B cells was studied in SJL mice. Phenotypically and functionally, B cells in the thymus of old SJL mice are mature B cells; IgM+, IgD+, Ly-1-, and evince a high proliferative response to lipopolysaccharide and a low one to dextran sulphate. Memory B cells can be found in the thymus of mice immunized with T-dependent or T-independent antigens. Chronic depletion and B cell maturation arrest induced by fractionated total lymphoid irradiation or by neonatal splenectomy eliminate B cells from the thymus and block their migration from the periphery to the thymus. When examined in adoptive transfer experiments, thymus B cells were found to possess a normal migration pattern and homing receptors; their migration pattern did not differ from that of lymph node or splenic B cells. It is evident, therefore, that the large number of normal functioning B cells in the thymus of SJL mice reflects a massive infiltration of the thymus by mature B cells from the periphery due to thymus dysfunction rather than to an abnormal in situ differentiation of intrathymic B cell precursors.     

EV71型手足口病乳鼠动物模型的建立及免疫、内分泌及病理特征研究

目的建立EV71型手足口病乳鼠动物模型并进行免疫、致病特性研究。方法将临床分离的EV71病毒株经蚀斑纯化,3T3细胞适应,乳鼠驯化,最终获得1株能致死7日龄乳鼠的EV71毒株,命名为BJ09/07(GenBank Accession NO.JQ319054,EV71-BJ)。EV71-BJ感染7日龄ICR乳鼠后,观测临床疾病得分、体质量变化、死亡率并测定病毒载量、免疫分子、内分泌水平、组织病理损伤等病毒、免疫、内分泌、病理指标。结果 EV71-BJ毒株感染7日龄ICR乳鼠,其病毒毒力为150 LD50/ml,感染后不同时期肌肉病毒载量均高于脑中,至第4天达到高峰,后不断下降。至感染后第6天发病达高峰时做病理检测,相对于脑组织,肌肉中有更严重的淋巴细胞浸润,引起更严重的炎性分子升高。肌肉研磨液和血清中MCP-1、IFN-γ、IL-6和TNF-α显著升高,而肾上腺素和皮质醇未见明显变化。结论初步建立了EV71型手足口病乳鼠动物模型,为药物筛选、疫苗研发及免疫机理研究奠定了基础。     

Propagation of the Kakegawa strain of bovine coronavirus in suckling mice,rats and hamsters

Summary The Kakegawa strain of bovine coronavirus was easily propagated in suckling mice. Infected animals died with nervous symptoms, and serial passage was readily accomplished by intracerebral inoculation with brain emulsions. The 3rd passage viral material from infected mice evoked the same disease in suckling mice, rats and hamsters inoculated by the intracerebral or by the subcutaneous route. Viruses recovered from mice, rats and hamsters could be clearly differentiated from mouse hepatitis virus strain 2 by the neutralization test.With 1 Figure     

Involution and regeneration of the thymus in mice,induced by bacterial endotoxin and studied by quantitative histology and electron microscopy

Lipopolysaccharide from S. typhosa, injected intraperitoneally into Swiss albino mice, produced acute thymic involution—maximal at 48 hours after injection, followed by regeneration that was complete within 5 to 7 days. Using tissues fixed and embedded for electron microscopy, cell counts were made with the light microscope and cytological details were examined in electron micrographs. The cellular events of involution and regeneration were similar to those produced by injection of adrenal glucocorticoids, but it remains to be determined whether or not endotoxin acts on the thymus by inciting adrenal cortical secretion. Involution appeared to be the result of both the death of small lymphocytes and reduced lymphopoiesis in the thymus. Within 48 hours, macrophages had cleared away the cellular debris and medullary epithelial cells showed signs of hypertrophy and increased putative secretory activity. Subsequently, large lymphocytes proliferated at an accelerated rate in the subcapsular cortex, the cortex grew in width by the accumulation of small lymphocytes, and regeneration ceased when the thymus had reached its former size. These observations provide circumstantial evidence for the hypothesis that in regeneration, medullary epithelial cells increase their production of a lymphopoietic hormone which stimulates mitotic proliferaton of cortical lymphocytes.     

Effects of injury to mice by microwave (2400 mHz) irradiation and subsequent recovery

Threshold values of power density (PD) and exposure at which the mortality did not exceed 0.1% were determined in experiments on 2200 mice. The rate of formation of the pathological changes and of repair reactions was found to be close to an exponential function of PD. The functional relations established describe the adaptive powers of mice to microwave irradiation quantitatively.Institute of Biophysics, Academy of Sciences of the USSR, Moscow (Presented by Academician of the Academy of Medical Sciences of the USSR N. N. Zhukov-Verezhnikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 7, pp. 55–57, July, 1979.     

Hypertrophy of the thymus and restoration of immune functions in mice and rats by gonadectomy

Hypertrophy of the thymus was observed in aging C57BL/6 mice, ranging in age from 4 to 20 months, which had been gonadectomized 2 months before the sacrifice, and the magnitude of thymic regeneration was more pronounced in male than in female. However, enhancement of anti-SRBC antibody response was observed only in female, but not in male mice regardless of age. Gonadectomy brought about not only thymic hypertrophy but also an increase in T cells and B cells in the spleen. An increase in T cell subpopulations was proportional in female mice, but disproportional in male. The disproportional increase of T cell subpopulations could account for the failure to enhance the anti-SRBC antibody response in male mice. Gonadectomy also resulted in the thymic hypertrophy in male and female young Wistar rats, but not in those which had been previously hypophysectomized.     

Relationship between the response to complete freund adjuvant, phytohemagglutinin, and subsequent tumor growth in mice.

Groups of inbred C3H mice selected on the basis of strong or weak PPD reactions after sensitization with complete Freund adjuvant had significantly different reactions to PHA. The growth rate of a methylcholanthrene-induced tumor, previously shown to elicit a cell-mediated immune response, was significantly different in these two groups of mice. The basis for the marked variation observed between members of an inbred mouse strain in response to CFA is not understood but may bear an important potential relationship to tumor growth.     

Effect of increased growth rate during the suckling period on subsequent body weight and muscle weight to body weight ratio

The effect of increased growth rate during the suckling period on subsequent body growth rate and muscle weight to body weight (MW/BW) ratio was examined in inbred and outbred male and female mice. Growth rate during the suckling period was increased by reducing litter size to 4 pups within six hours of birth. Body weight, MW/BW ratio, and dry weight to wet weight (DW/WW) ratio for the soleus, tibialis anterior, extensor digitorum longus, biceps brachii, and heart muscles were measured at 4, 8, 16, and 24 weeks of age. The results indicate that increasing growth rate during the suckling period results in an increased body weight at 24 weeks of age in outbred male and female mice; whereas, in inbred male and female mice body weight is greater at 4 weeks of age but by 8 weeks of age the mice raised in normal litters have "caught up" with those raised in small litters. MW/BW ratio is increased in several muscles during the suckling period but returns to normal during the post weaning period.     

Characterization of intermediate T-cell receptor cells expanding in the liver, thymus and other organs in autoimmune lpr mice: parallel analysis with their normal counterparts.

Autoimmune MRL-lpr/lpr (lpr) mice were previously demonstrated to have an abnormal proliferation of intermediate T-cell receptor (TCR) cells of extrathymic origin in the liver. Despite this situation, thymectomy in lpr mice resulted in amelioration of autoimmune disease. To understand the underlying mechanism, we investigated associated T-cell differentiation in the thymus and other organs of these mice. When the disease was evoked, T cells with extrathymic properties, i.e. intermediate TCR-alpha beta cells expressing double-negative (DN) CD4-8- phenotype and interleukin-2 (IL-2) receptor beta-chain, became prominent not only in the liver, but also in the thymus. Such thymic T cells mainly resided in the medulla. A small-scale localization of such T cells was seen in the thymic medulla even in normal control mice. There was a heterogeneity among intermediate TCR cells in terms of the composition of DN cells and the expression of CD2 and B220 antigens, depending on the organs and the sites in the same organ. Intermediate TCR cells in the liver, thymus and autoimmune target organs (e.g. kidney) contained a high proportion of the active form (CD2+B220-), while intermediate TCR cells accumulating in peripheral organs, the spleen and lymph nodes, were mainly of the inactive form (CD2-B220+). The active form had an ability to proliferate in response to IL-2 and SEB, whereas the inactive form did not. The present results suggest that the proliferation of intermediate TCR cells occur at multiple sites; this may explain the effect of thymectomy, namely, the retarded onset of disease, in lpr mice.     

Uptake and disposal of BSA-coated latex particles by the rat mesangium: reaction with subsequently administered heterologous antiserum

Mesangial uptake and disposal of antigen-coated latex particles and the ability of subsequently injected antibody to maintain complexed antigen in the rat mesangium has been investigated. Carboxylate-modified latex particles, coated with bovine albumin (BSA) were injected i.v. to 36 Wistar rats. Twenty-two rats (group 1) were not treated further. Fourteen rats (group 2) received rabbit anti-BSA antiserum i.v. and i.p. 24 h later. Control groups were injected with uncoated, unmodified latex particles or soluble BSA with and without subsequent antibody administration. Latex was present in the mesangial matrix of rats in group 1 at 1 h in association with a diffuse mesangial distribution of BSA. At 24 h, BSA staining was markedly reduced and extracellular latex was no longer observed. Intracellular latex aggregates were present in experimental and control groups at 24 h-14 days in cytoplasmic vacuoles of hypertrophic mesangium which showed minor infiltration by macrophage-like cells. Progressive removal of latex aggregates coincided with declining mesangial reactivity. Rapid disappearance of antigen apparently results from local degradation of tracer in the mesangium. Antibody administration preserves BSA in the mesangium due to immune complex formation and is associated with retention of ingested latex by mesangial cells. However, efficient disposal of glomerular immune deposits by the mesangium appears to minimize infiltration by monocytes and prevents aggravation of glomerular inflammation.     

Inhibition by the protein kinase inhibitors, isoquinolinesulfonamides, of fluid accumulation induced by Escherichia coli heat-stable enterotoxin, 8-bromo-cGMP and 8-bromo-cAMP in suckling mice

The effects of isoquinolinesulfonamides, which inhibit protein kinase, on fluid accumulations induced by heat-stable enterotoxin of enterotoxigenic Escherichia coli (STh), 8-bromo-cGMP and 8-bromo-cAMP in suckling mice were studied. Both N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide (H-8) and N-(2-aminoethyl)-5-isoquinolinesulfonamide (H-9) inhibited the fluid accumulation induced by STh. Fluid accumulation induced by four mouse units of STh (four-fold the minimum effective dose, 10 ng) was completely inhibited by 0.4 mumol of H-8 or H-9. H-8 and H-9 also inhibited fluid accumulation induced by 8-bromo-cGMP. On the other hand, H-8 and H-9 only partially inhibited fluid accumulation in suckling mice induced by 8-bromo-cAMP, probably because their affinities to cAMP-dependent protein kinase were lower than their affinities to cGMP-dependent protein kinase. From these results, it is concluded that the activation of cGMP-dependent protein kinase by increase in cGMP by ST or by 8-bromo-cGMP, and very probably the activation of cAMP-dependent protein kinase by increase in cAMP by cholera enterotoxin and heat-labile enterotoxin of enterotoxigenic E. coli and by 8-bromo-cAMP are necessary steps in signal transduction following increases in concentrations of cGMP and cAMP in intestinal brush border cells.     

Immunosuppression with busulphan: the effect on spleen, marrow and thymus cells of mice

The immunosuppressive activity of busulphan, an anti-tumor agent, was studied using cell-transfer experiments. Spleen cells from busulphan-treated donors were many times less active than normal cells, while normal cells could restore competence to busulphan-treated mice. It was concluded that the drug acts directly upon immunocompetent cells, but has no effect upon the environment in which they work. Further experiments showed that spleen from busulphan-treated donors did not show synergy with normal marrow or thymus cells, and that neither marrow nor thymus cells from these donors show synergy with the reciprocal normal cell. It was concluded that busulphan affects both thymus-dependent (T) and thymus-independent (B) cells. However, marrow alone restored competence to busulphan-treated recipients which, therefore, must contain an excess of T cells. This may be because mice normally contain an excess of T cells, or because there is a subpopulation of T cells outside the thymus and spleen, unaffected by busulphan.     

Pathology of rotavirus infection in suckling mice: A study by conventional histology, immunofluorescence, ultrathin sections, and scanning electron microscopy

Pathologic changes induced in the small intestine of suckling mice by rotavirus infection were studied by conventional histology, immunofluorescence, scanning electron microscopy, and electron microscopy of ultrathin sections. Infection could be detected within 24 hours in a few mice, but after 2 days it was well established. Swollen, often vacuolated infected cells were found on the sides and tips of villi from which they rapidly became detached; microvilli showed variable irregularity. Immature enterocytes from crypts replaced lost infected cells. By the tenth day very few infected cells could still be found. Both tubular structures and spherical particles occurred in the infected cells. Only tubular structures were found in nuclei.