Oxytalan fibres in the periodontal ligament of equine molar cheek teeth

The distribution and arrangement of oxytalan fibres were examined in periodontal specimens of cheek teeth from seven horses. Oxidation prior to aldehyde fuchsin exposition permitted a selective staining of the oxytalan fibres, which are a distinct component of the elastic fibre system. On three horizontal levels of the periodontium--(a) subgingival, (b) middle third and (c) apical--two oxytalan fibre groups were shown histologically: 'blood vessel-related' and 'independent' oxytalan fibres. In levels a and b, both groups were arranged in a typical occluso-apical alignment along the reserve crown. Single oxytalan fibres deviated from their general course in order to attach to the cementum. In these cemental entheses the oxytalan fibres ran parallel to collagen fibre bundles. The interpretation of such morphological features emphasized the oxytalan fibres' capacity to improve the stability of periodontal blood vessel walls during masticatory movements. Level c, especially in regions next to the persisting epithelial root sheath, is the site of oxytalan fibre generation. This is a prerequisite for the facilitation of periodontal regeneration and reorganization during dental growth and eruption.     

Mitigating an undesirable immune response of inherent susceptibility to cutaneous leishmaniosis in a mouse model: the role of the pathoantigenic HISA70 DNA vaccine

ABSTRACT: Leishmania major is the major cause of cutaneous leishmaniosis (CL) outside of the Americas. In the present study we have cloned six Leishmania genes (H2A, H2B, H3, H4, A2 and HSP70) into the eukaryotic expression vector pCMVbeta-m2a, resulting in pCMV-HISA70m2A, which encodes all six pathoantigenic proteins as a single polyprotein. This expression plasmid has been evaluated as a novel vaccine candidate in the BALB/c mouse model of CL. The DNA vaccine shifted the immune response normally induced by L. major infection away from a Th2-specific pathway to one of basal susceptibility. Immunization with pCMV-HISA70m2A dramatically reduced footpad lesions and lymph node parasite burdens relative to infected control mice. Complete absence of visceral parasite burden was observed in all 12 immunized animals but not in any of the 24 control mice. Moreover, vaccinated mice produced large amounts of IFN-gamma, IL-17 and NO at 7 weeks post-infection (pi), and they showed lower arginase activity at the site of infection, lower IL-4 production and a weaker humoral immune response than infected control mice. Taken together, these results demonstrate the ability of the HISA70 vaccine to shift the murine immune response to L. major infection away from an undesirable, Th2-specific pathway to a less susceptible-like pathway involving Th1 and Th17 cytokine profiles.     

Duration of strain 2308 infection and immunogenicity of Brucella abortus lipopolysaccharide in five strains of mice

A study was conducted to compare immunogenicity of a Brucella abortus lipopolysaccharide (LPS) and the duration of infection in 5 strains of mice. Mice of strains CBA/NJ, BALB/c, CD-1, C3H/HeN, and C3H/HeJ were allotted into 2 large groups (vaccinated with proteinase K-treated LPS or nonvaccinated) and 6 subgroups based on the intervals between challenge exposure to B abortus strain 2308 and the week the response data were obtained. Criteria used in comparing responses between the various strains of mice as well as between vaccinated and nonvaccinated mice were splenomegaly, colony-forming units (CFU) from spleens, and antibody titers. Responses were evaluated at 1, 2, 3, 5, 8, and 12 weeks after challenge exposure. Results indicated that all strains of mice became infected and maintained infection throughout the 12-week period, the percentages of mice infected were significantly (P less than 0.05) less in vaccinated mice for the first 5 weeks after challenge exposure, and there were no direct correlations between increased immunoglobulins (IgM and IgG titers) and reduction in CFU. Vaccinated mice of strains BALB/c, CD-1, C3H/HeN, and C3H/HeJ had increased titers when challenge exposed and also had significantly (P less than 0.05) smaller spleens and lower CFU. Vaccinated CBA/NJ mice did not have marked antibody titers. The overall results indicated that vaccination with LPS offers some initial protection against B abortus strain 2308 infection, but this protection disappears gradually and in various degrees in the 5 strains of mice studied.     

Comparison of gastritis and gastric epithelial proliferation in Helicobacter heilmannii-infected nude and BALB/c mice

Gastric mucosal hypertrophy/nodular hyperplasia occurs as a consequence of Helicobacter infection in mice and humans. The pathogenesis of this hyperplastic response is not understood. To determine the role of host cellular immunity in gastric mucosal hypertrophy/hyperplasia, 6-8-week-old female euthymic BALB/c (n = 30) or NIH athymic nude (n = 40) mice were inoculated with H. heilmannii. Equal numbers of uninoculated mice of each strain served as controls. Mice from each group were euthanatized at 0.5, 6, 12, and 18 months postinoculation (PI). Lymphoplasmacytic gastritis and lymphoid follicle development were less severe in nude mice than in euthymic mice at <6 months PI. The prevalence of gastritis at 0.5, 6, 12, and 18 months PI was 0%, 17%, 67%, and 88%, respectively, in infected nude mice and 33%, 83%, 71%, and 100%, respectively, in infected BALB/c mice. CD4+ T cells in infected nude mice were evident at > or =6 months PI but were less numerous than in infected BALB/c mice at comparable time intervals. However, numbers of CD4+ T cells increased substantially throughout the experiment in infected BALB/c mice. The prevalence of nodular mucosal hyperplasia at 0.5, 6, 12, and 18 months PI was 0%, 0%, 33%, and 20%, respectively, in infected nude mice and 0%, 33%, 80%, and 80%, respectively, in infected BALB/c mice. Nodular hyperplasia occurred in association with the appearance of chronic lymphoplasmacytic inflammation and CD4+ T cells at 12 and 18 months PI in nude mice. H. heilmannii-associated gastritis and mucosal remodeling is reduced in immunodeficient mouse strains lacking normal CD4+ T cell numbers as compared with the response in immunocompetent mice. Additionally, CD4 immunocompetence is an integral aspect of the mucosal hypertrophy/nodular hyperplasia in experimental H. heilmannii-associated disease of mice.     

Mechanisms of immunity to Leishmania major infection in mice: the contribution of DNA vaccines coding for two novel sets of histones (H2A-H2B or H3-H4)

The immune phenotype conferred by two different sets of histone genes (H2A-H2B or H3-H4) was assessed. BALB/c mice vaccinated with pcDNA3H2AH2B succumbed to progressive cutaneous leishmaniosis (CL), whereas vaccination with pcDNA3H3H4 resulted in partial resistance to Leishmania major challenge associated with the development of mixed T helper 1 (Th1)/Th2-type response and a reduction in parasite-specific Treg cells number at the site of infection. Therefore, the presence of histones H3 and H4 may be considered essential in the development of vaccine strategies against CL based on the Leishmania histones.     

Histopathological studies of visceralized Leishmania (Leishmania) amazonensis in mice experimentally infected

BALB/c, C57BL/6, and DBA/2 mice were subcutaneously infected in the left footpad by injecting 10(4) Leishmania (Leishmania) amazonensis amastigotes. Mice were sacrificed 20, 30, 40, 60 and 90 days post-infection. Fragments of liver, kidney, spleen, skin, and draining lymph node were collected for histological examination. Light microscopy showed that at 20 days after infection BALB/c mice presented discrete inflammatory infiltrates in the skin made up of eosinophils, lymphocytes, and rare parasitized macrophages. Ninety days post-infection, the dermis showed necrotic tissue, large numbers of mononuclear cells and vacuolated macrophages filled with amastigotes. Forty days post-infection, the draining lymph nodes showed hyperplastic germinal centers, increase of high endothelial venules and apoptosis in germinal center cells. After the first 3 months post-infection, the involvement of spleen, kidney and liver was discreet, being characterized by multifocal inflammatory infiltrates. Eight months after infection, the animals presented metastatic lesions in the contralateral footpad and nose. In deep dermis, there was remarkable proliferation of fibroblasts associated with collagen fibers. The liver showed multifocal granulomas and mononuclear infiltrate around the blood vessels, but no parasites were observed, except in one animal. In some mice there were immature cells of the hematopoietic lineage. Both BALB/c and C57BL/6 mice presented osteonecrosis, which is characterized by pycnotic osteocytes and empty lacunae at the point of inoculation and subsequently, replacement of this tissue by fibrous connective tissue and colonization of the bone marrow. A diffuse inflammatory process composed of mononuclear cells and rare parasites were seen in the kidneys. In one mouse, bone marrow cells were observed in the renal medulla along with where free amastigotes. DBA/2 mice developed a mild infection and they did not visceralize. In conclusion, our data demonstrates that in susceptible mice L. (L.) amazonensis, a causative agent of tegumentary leishmaniasis, causes pathological changes similar to those produced by Leishmania (L.) infantum in both humans and canids.     

Infections in immunocompetent and immune-deficient mice with promastigotes of a North American isolate of Leishmania infantum

Leishmania infantum, an etiologic agent of zoonotic visceral leishmaniasis, is widespread among foxhounds in the United States. Experimental infections with a North American isolate of L. infantum were evaluated using two inoculation routes in immunocompetent and immunosuppressed mouse strains. Groups of 2-5 interferon gamma gene knockout (IFN-gamma-KO) (BALB/c-Ifng), inducible nitric oxide synthase (NOS) gene knockout (iNOS-KO) (C57BL/6), B-cell-deficient (microMT) (C57BL/6), and BALB/c mice were intravenously (i.v.) or subcutaneously (s.c.) inoculated with various doses of promastigotes of the LIVT-1 strain of L. infantum. None of the mice developed clinical signs of leishmaniasis during the 8-9 weeks of the study. Promastigotes were cultured from spleens of all i.v.-infected mice by 3 days post culture. Spleens from s.c.-infected mice inoculated with greater than 1 x 10(6) parasites became culture positive 3-24 days post culture, but promastigotes were not cultured from mice infected with 1 x 10(5) or 5 x 10(5) LIVT-1 promastigotes. Histological lesions were prominent in the livers of i.v.-infected mice but were mild to nonexistent in s.c. infection. Serological responses were low and transient determined by indirect fluorescent antibody testing in all groups. These results indicate that the i.v. route of infection is superior to the s.c. route in a mouse model of North American leishmaniasis and that mice lacking INF-gamma, iNOS or mice that are B-cell-deficient are not more susceptible to acute infection.     

Interleukin-6 is produced during both murine and avian Eimeria infections

The production of interleukin-6 (IL-6) during Eimeria infection was investigated in an attempt to gain a better understanding of the role of this multi-functional cytokine in resistance to this parasite. IL-6 production was measured in both chickens, in which the disease is of economic importance, and the better-characterised murine model system.Systemic and local IL-6 production in mice during E. vermiformis infection was investigated, in the relatively resistant BALB/c strain, and the relatively susceptible C57 BL/6 strain, using a murine IL-6 ELISA and the 7TD1 assay. Enhanced systemic production of IL-6 in serum was seen in infected BALB/c mice when compared to C57 BL/6 mice. This difference was also reflected in the draining lymph node of the site of infection, assessed by testing supernatants from stimulated mesenteric lymph node cells taken from infected mice at different times post-infection.Production of chicken IL-6-like factor activity was investigated using a murine IL-6 7TD1 bioassay. The presence of substantial quantities of IL-6-like factor activity was detected in serum taken from some chickens infected with E. tenella during the course of primary infection and, in a separate experiment, during the first few hours post-infection, a time when the pro-inflammatory capacity of IL-6 would influence the developing immune response. These results suggest that IL-6 is also important in the induction of immune effector responses to Eimeria infections in the chicken.     

Immunologic, histopathologic, and bacteriologic responses of five strains of mice to Brucella abortus strain 2308

A study was conducted to establish baseline data on Brucella abortus infection induced in 5 strains of mice (CBA/NJ, BALB/c, CD-1, C3H/HeN, and C3H/HeJ). The strains were compared on the basis of immunologic, histopathologic, and bacteriologic responses. There were 4 treatment groups for each strain of mice: (1) vaccinated with homologous lipopolysaccharide and challenge exposed to B abortus strain 2308; (2) not vaccinated but challenge exposed; (3) vaccinated and not challenge exposed; and (4) not vaccinated and not challenge exposed. Results indicated that mice can be used for comparative studies on the pathogenesis and immunogenesis of B abortus infections; strains of mice may vary in their responses to Brucella infection, regardless of their vaccination status. Bacteriologic and immunologic responses in mouse strains BALB/c, CD-1, C3H/HeN, and C3H/HeJ, but not those of CBA/NJ, were extrapolative among strains.     

蜥蜴利什曼原虫在小鼠体内的分布及增殖研究

通过腹腔途径用体内含有荧光蛋白的蜥蜴利什曼原虫感染BALB/c小鼠,感染后采其脏器做冰冻切片,荧光染料染色后用荧光显微镜观察,并经PCR鉴定,结果显示蜥蜴利什曼原虫感染小鼠后,主要分布于心脏、肝脏、脾脏、肺脏、肾脏。另外,成功建立了利什曼原虫荧光定量PCR检测方法,并采用该方法检测感染蜥蜴利什曼原虫后BALB/c小鼠体内利什曼原虫的增殖情况,结果显示,感染13 d内,BALB/c小鼠体内蜥蜴利什曼原虫呈波浪状增殖。这一结果为研究蜥蜴利什曼原虫感染人和动物的致病机理和免疫方法及疫苗研制等方面提供了基础理论依据。     

KM和BALB/c小鼠痘病毒感染的诊断

20只外购的KM和BALB/c小鼠发生了酷似鼠脱脚病的典型症状，取病鼠的肝、脾、肾、淋巴结和脑作组织学检查，发现其病理变化呈痘病毒感染的特征性改变，组织镁浆液接种传代的BHK细胞，可发生明显的CPE变化，经电镜超薄切征及负染检查发现大量的痘病毒颗粒，粒子的中心为DNA核酸和蛋白质组成的拟核，在衣壳的外面有囊膜包裹，对鸡红细胞均呈阳性凝集反应（HA为1：16），用小鼠痘病毒ELISA试剂盒检测病鼠血清呈阳性反应，用病毒悬液免疫接种KM和BALB／C小鼠后，发现前者感染性强，发病快，症状典型，以急性为主，并迅速出现死亡。后者对鼠痘抵抗力强，一般呈陷性感染，特征性症状出现较缓慢，但后者一旦施加实验因素动物则出现症状，也可迅速死亡。实验证明，该群小鼠患的传染病病原为鼠痘病毒。     

The local immune response of mice after Helicobacter suis infection: strain differences and distinction with Helicobacter pylori

Helicobacter (H.) suis colonizes the stomach of pigs and is the most prevalent gastric non-H. pylori Helicobacter species in humans. Limited information is available on host immune responses after infection with this agent and it is unknown if variation in virulence exists between different H. suis strains. Therefore, BALB/c and C57BL/6 mice were used to compare colonization ability and gene expression of various inflammatory cytokines, as determined by real-time PCR, after experimental infection with 9 different H. suis strains. All strains were able to persist in the stomach of mice, but the number of colonizing bacteria at 59 days post inoculation was higher in stomachs of C57BL/6 mice compared to BALB/c mice. All H. suis strains caused an upregulation of interleukin (IL)-17, which was more pronounced in BALB/c mice. This upregulation was inversely correlated with the number of colonizing bacteria. Most strains also caused an upregulation of regulatory IL-10, positively correlating with colonization in BALB/c mice. Only in C57BL/6 mice, upregulation of IL-1β was observed. Increased levels of IFN-γ mRNA were never detected, whereas most H. suis strains caused an upregulation of the Th2 signature cytokine IL-4, mainly in BALB/c mice. In conclusion, the genetic background of the murine strain has a clear impact on the colonization ability of different H. suis strains and the immune response they evoke. A predominant Th17 response was observed, accompanied by a mild Th2 response, which is different from the Th17/Th1 response evoked by H. pylori infection.     

Heligmosomoides polygyrus and Trypanosoma congolense infections in mice: effect of immunisation by abbreviated larval infection.

Concurrent African trypanosome and gastrointestinal helminth infections are prevalent in sub-humid savannah where they are endemic. However, acquired resistance in animals varies with their responder status and exposure. As a guide to study in the definitive hosts, the effects of Trypanosoma congolense infection on the development and maintenance of homologous Heligmosomoides polygyrus resistance were investigated in outbred TO mice. These mice were immunised by abbreviation of larval infection. Immune or naive mice were either infected with 500 infective larvae (L3) of H. polygyrus and/or 10(4) bloodstream forms of T. congolense or were not infected. The outcome of infection was monitored by routine parasitological and immunological techniques for 30 days after the day of the T. congolense infection. Significantly more immune mice concurrently infected with both parasites survived than did immune mice in which H. polygyrus was superimposed on a 10-day-old T. congolense infection. Although all the mice in this latter group died before the end of the experiment, larval immunisation prolonged their survival, relative to similarly treated naive mice. The antibody titres to H. polygyrus in the sera of immune mice challenged with H. polygyrus alone were significantly higher than those of immune mice concurrently infected with both parasites but the levels of protection obtained were comparable. It is concluded that T. congolense may not completely block the strong acquired resistance induced by abbreviated H. polygyrus larval infection in TO mice but is capable of interfering with protective responses, especially if the trypanosome infection occurs prior to H. polygyrus challenge infection.     

C5a/C5aR信号在微小隐孢子虫感染中的免疫调节作用研究

旨在探究C5a/C5aR信号在微小隐孢子虫感染过程中对宿主CD4⁺ T细胞免疫反应的调控作用。本研究以微小隐孢子虫（Cryptosporidium parvum）为研究对象,以BALB/c乳鼠和C5aR抑制BALB/c乳鼠为感染模型,应用实时荧光定量PCR和免疫组织化学技术检测了C.parvum感染前后乳鼠回肠组织中C5aR的表达变化,利用实时荧光定量PCR检测了隐孢子虫HSP70基因和CD4⁺ T细胞亚群（Th1、Th2、Th17细胞和Treg细胞）主效应细胞因子（IFN-γ、IL-4、IL-17和TGF-β）的转录变化,并通过病理组织切片观察乳鼠回肠黏膜的损伤情况。结果显示：与对照组乳鼠相比,C.parvum感染可以引起乳鼠回肠组织中C5aR的mRNA和蛋白表达水平显著上调（P<0.05）,以及IFN-γ表达水平显著上调（P<0.05）;与C.parvum感染组乳鼠相比,C5aR抑制剂处理可引起C.parvum感染乳鼠回肠组织中Th1细胞、Th2细胞和Treg细胞的主效应细胞因子IFN-γ、IL-4和TGF-β显著下调表达（P<0.05）,以及Th17细胞主效应细胞因子IL-17显著上调表达（P<0.05）。病理学观察发现,抑制C5aR能显著改善C.parvum感染引起的乳鼠回肠组织的绒毛直径和黏膜厚度变化（P<0.05）,但不能改善绒毛长度、绒毛长度与隐窝深度比值。隐孢子虫HSP70基因的mRNA水平检测发现,抑制C5aR能显著影响C.parvum在回肠组织中的增殖（P<0.05）。C5a/C5aR信号可能通过动态调节CD4⁺ T细胞亚群主效应细胞因子的表达来参与宿主与隐孢子虫相互作用的过程,为深入理解隐孢子虫与宿主的互作机制提供了参考。     

H5N1亚型禽流感病毒低剂量感染小鼠发病模型的建立

为模拟哺乳动物感染H5亚型高致病性禽流感病毒(HPAIV)的发病进程,本研究采用对哺乳动物高度致病的H5N1亚型HPAIV株A/bar-headed goose/Qinghai/3/05 (BHG/3/05),以低剂量鼻腔接种小鼠,观察发病、存活、病毒复制及组织病理损伤情况.结果显示,100.4 EID50即能够100％感染小鼠,但发病表现缓慢,死亡延迟至8d以后,存活达60％;体内病毒复制可持续10 d以上,感染后前3d病毒的增殖限于呼吸道,随后扩散至脑、脾、肾等其他器官;组织病理学观察肺脏早期表现出渗出性炎症,第10d发展为典型的间质性肺炎.本研究结果为探讨人禽流感的病理发生机制提供了具有价值的模型.     

近交系小鼠RAPD标记的观察

采用随机扩增多态性DNA技术(RAPD),分析BALB/c、C57BL/6、DBA/2、C3H/He等4个近交系小鼠的基因多态性,探讨用RAPD作为遗传标记,对近交系小鼠进行遗传检测。结果表明,4种小鼠表现出了各自不同的多态性RAPD标记,证明RAPD可作为近交系小鼠的分子标记,在DNA水平区别4种近交系小鼠。     

The genetic basis of host resistance to Bacillus anthracis in inbred mice

Inbred mice of the C3H/He (resistant) and C57BL/6 (susceptible) strains and their hybrids were used in experiments to investigate the genetic regulation of host resistance to B. anthracis. The susceptibility of F1 mice to a standard spore suspension was similar to that of the resistant parent and not intermediate between values for the parent strains. There were no differences in mortality rate between F1 and reciprocal cross mice. Analysis of the results indicated that resistance of mice to B. anthracis is regulated by a single dominant gene.     

Cryptosporidium parvum: investigation of sporozoite excystation in vivo and the association of merozoites with intestinal mucus

Enteric cryptosporidiosis was studied in the small intestine of five-day-old sucking mice after infection with 10(6) Cryptosporidium parvum oocysts. It was shown that excystation and the majority of subsequent endogenous stages occurred predominantly in the ileum. During the first three days of infection the number of merozoites collected in ileal washings increased over 100-fold to approximately 10(6) merozoites per mouse on the third day. In contrast to control mice, wash fluid from infected mice contained numerous strands of dislodged mucus. Estimates of mucus in the ileal washings of infected mice were similar to those made in controls until day 4 after infection when they increased and remained high throughout the remainder of the experiment. This study describes a method whereby ileal mucus washings from C parvum infected infant mice could be used as a rich source of merozoites.     

Mechanisms of resistance and susceptibility to experimental visceral leishmaniosis: BALB/c mouse versus syrian hamster model

ABSTRACT: Several animal models have been established to study visceral leishmaniosis (VL), a worldwide vector-borne disease affecting humans and domestic animals that constitutes a serious public health problem. BALB/c mice and Syrian hamsters are the most widely used experimental models. In this paper, we summarize the advantages and disadvantages of these two experimental models and discuss the results obtained using these models in different studies of VL. Studies using the BALB/c mouse model have underscored differences between the liver and spleen in the course of VL, indicating that pathological evaluation of the visceral organs is essential for understanding the immune mechanisms induced by Leishmania infantum infection. The main goal of this review is to collate the relevant literature on Leishmania pathogenesis into a sequence of events, providing a schematic view of the main components of adaptive and innate immunity in the liver and spleen after experimental infection with L. infantum or L. donovani. This review also presents several viewpoints and reflections about some controversial aspects of Leishmania research, including the choice of experimental model, route of administration, inoculum size and the relevance of pathology (intimately linked to parasite persistence): a thorough understanding of which is essential for future VL research and the successful development of efficient control strategies for Leishmania spp.