Chemokines expression during Leptospira interrogans serovar Copenhageni infection in resistant BALB/c and susceptible C3H/HeJ mice

The role of innate immune responses in protection against leptospirosis remains unclear. We examined the expression of the chemokines CCL2/JE (MCP-1), CCL3/MIP-1 alpha (MIP-1 alpha) and CXCL1/KC (IL-8) regarding resistance and susceptibility to leptospirosis in experimental mice models BALB/c and C3H/HeJ, respectively. A virulent strain of Leptospira interrogans serovar Copenhageni was used in this study. Twenty-five animals of each mouse strain of C3H/HeJ and BALB/c, were infected intraperitoneally with 106 cells. Five un-infected animals of each strain were kept as control. Mortality of C3H/HeJ mouse was observed while BALB/c mice were asymptomatic. The presence of leptospire DNA in tissues of infected animals was demonstrated by PCR. Chemokines were measured in serum, spleen, liver, kidney and lung of both strains of animals using immunoenzymatic assay (ELISA). Elevations in the levels of chemokines MCP-1 and IL-8 occurred in all organs and sera of C3H/HeJ and BALB/c infected mice. The levels of MIP-1 alpha were lower when compared to MCP-1 and IL-8 in all analyzed organs, with a slight increase in liver and kidney. Our results indicate that the expression of inflammatory mediators can vary greatly, depending on the tissue and mouse strains. It is possible that the resistance to Leptospira can be partially correlated to the increase of MIP-1 alpha observed in BALB/c mice, while an increasing and a sustained expression of MCP-1 and IL-8 in the lungs of C3H/HeJ mice can be correlated to the severity and progression of leptospirosis. (C) 2009 Elsevier Ltd. All rights reserved.

Atypical epidermal alterations in chronic Leishmania mexicana mexicana lesions fo C3H mice

C3H mice chronically infected with Leishmania m. mexicana, and in some groups treated with BCG or levamisole, presented atypical epidermal alterations, including pseudoepitheliomatous hyperplasia, hyperkeratosis and dysplasia. These alterations increased in frequency and intensity during the course of infection, but were not related to lesion size or tissue parasite load. Age matched normal, BCG and levamisole treated control mice, examined simultaneously, did not show epidermal modifications. In infected mice the dermis and hypodermis presented an inflammatory infiltrate of histiocytes, lymphocytes and plasma cells, accompanied at times by neutrophils and eosinophils, which did not vary with duration of infection.

Caracterização biológica de clones das cepas Y, CL e MR de Trypanosoma cruzi em camundongos C3H isogênicos

Dez clones isolados das cepas Y, CL e MR foram caracterizados segundo infectividade das culturas, curvas de parasitemia, polimorfismo e mortalidade em camundongos C3H isogênicos. Entra os clones das cepas Y e CL foram encontradas diferenças intragrupos bastante significativas. Os clones da cepa MR apresentaram maior homogeneidade. Estes resultados indicam que as cepas do T. cruzi podem apresentar diferentes graus de heterogeneidade. Também sugerem que as condições utilizadas para a manutenção de cepas de T. cruzi podem resultar em vantagens seletivas para algumas subpopulações, podendo uma cepa ser o resultado da interação destas subpopulações (clones) selecionadas após alguns anos de manutenção em laboratório.

Trypanosoma cruzi infection in offspring born to chagasic C3H/He mice

This study reports the effects of Trypanosoma cruzi infection induced in C3H/He male and female mice born to chagasic mice. An experimental model was established infecting female C3H/He mice with a low virulent T. cruzi clone. In this model, mating, fertilization, pregnancy evolution and delivery was carried out successfully. The offspring was infected at four, six and eigth weeks of age. The results showed that the offspring born to chagasic mothers present decreased resistance to acquired T. cruzi infection. This decreased resistance was expressed by higher levels of parasitaemia and higher mortality rates in offspring born to chagasic mothers than in controls. Age and sex were shown to be important factors of this phenomenon. The results suggest that maternal immune system products can modulate the immune response of the offspring.

Natural Schistosoma mansoni infection in Nectomys squamipes: histopathological and morphometric analysis in comparison to experimentally infected N. squamipes and C3H/He mice

Histopathologic and morphometric (area, perimeter, major and minor diameters) analysis of hepatic granulomas isolated from twelve naturally infected Nectomys squamipes were compared to four experimentally infected ones and six C3H/He mice. Liver paraffin sections were stained for cells and extracellular matrix. Both groups of N. squamipes presented peculiar granulomas consisting predominantly of large macrophages, full of schistosome pigment, characterizing an exudative-macrophage granuloma type, smaller than the equivalent granuloma type in mouse. Naturally infected animals exhibited granulomas in different stages of development, including large number of involutional types. Morphometric analysis showed that all measurements were smaller in naturally infected animals than in other groups. The results demonstrated that both N. squamipes groups reproduced, with small variations, the hepatic granuloma aspects already described in cricetidium (Calomys callosus), showing a genetic tendency to set up strong macrophage responses and small granulomas. Unexpectedly, natural infection did not engender distinguished histopathological characteristics distinct from those derived from experimental single infection, showing changes predominantly secondary to the duration of infection. It appears that the variability of the inocula (and the number of infections?) interfere more with the quantity than with the quality of the pathological changes, denoting some morpho-functional determinism in the response to schistosomal infection dependent on the animal species.

A comparative parasitologic study on Biomphalaria glabrata snail and C3H/He mice infected with human and murine isolates of Schistosoma mansoni derived from Sumidouro, Rio de Janeiro, Brazil

Experiments were carried out to analyze the biological characteristics of two sympatric isolates of Schistosoma mansoni derived from humans and murines in a low endemic transmission area (Sumidouro county, state of Rio de Janeiro, Brazil). Sympatric reared-laboratory Biomphalaria glabrata and C3H/He mice were used as experimental hosts. Parameters assessed comprised: precercarial period, infectivity and mortality (snails), prepatent period, infectivity (percentage of cercariae maturation into adult worm) and intestinal egg count (mice). The murine isolate showed a shorter precercarial period and higher infectivity than human isolate (p < 0.05). This biological heterogenicity did not correspond to the vertebrate data because any biological parameter presented significant difference (p > 0.05). These data suggest that both isolates are local sub-populations, providing support for the hypotheses that in a same biotope mixed populations or sub-populations circulate among their main host (human beings) and/or rodent as an anfixenous infection.

Presence of the Gpr179(nob5) allele in a C3H-derived transgenic mouse

PURPOSE To identify the mutation responsible for an abnormal electroretinogram (ERG) in a transgenic mouse line (tg21) overexpressing erythropoietin (Epo). The tg21 line was generated on a mixed (C3H; C57BL/6) background and lacked the b-wave component of the ERG. This no-b-wave (nob) ERG is seen in other mouse models with depolarizing bipolar cell (DBC) dysfunction and in patients with the complete form of congenital stationary night blindness (cCSNB). We determined the basis for the nob ERG phenotype and screened C3H mice for the mutation to evaluate whether this finding is important for the vision research community. METHODS ERGs were used to examine retinal function. The retinal structure of the transgenic mice was investigated using histology and immunohistochemistry. Inverse PCR was performed to identify the insertion site of the Epo transgene in the mouse genome. Affected mice were backcrossed to follow the inheritance pattern of the nob ERG phenotype. Quantitative real-time PCR (qRT PCR), Sanger sequencing, and immunohistochemistry were used to identify the mutation causing the defect. Additional C3H sublines were screened for the detected mutation. RESULTS Retinal histology and blood vessel structure were not disturbed, and no loss of DBCs was observed in the tg21 nob mice. The mutation causing the nob ERG phenotype is inherited independently of the tg21 transgene. The qRT PCR experiments revealed that the nob ERG phenotype reflected a mutation in Gpr179, a gene involved in DBC signal transduction. PCR analysis confirmed the presence of the Gpr179(nob5) insertional mutation in intron 1 of Gpr179. Screening for mutations in other C3H-derived lines revealed that C3H.Pde6b(+) mice carry the Gpr179 (nob5) allele whereas C3H/HeH mice do not. CONCLUSIONS We identified the presence of the Gpr179(nob5) mutation causing DBC dysfunction in a C3H-derived transgenic mouse line. The nob phenotype is not related to the presence of the transgene. The Gpr179(nob5) allele can be added to the list of background alleles that impact retinal function in commonly used mouse lines. By providing primers to distinguish between Gpr179 mutant and wild-type alleles, this study allows investigators to monitor for the presence of the Gpr179(nob5) mutation in other mouse lines derived from C3H.

MOUSE MAMMARY TUMOR VIRUS EPITOPES EXPRESSED ON TUMOR SPECIFIC TRANSPLANTATION ANTIGENS OF CHEMICALLY INDUCED C3H/HEJ SARCOMAS (TSTA, FIBROSARCOMA, CARCINOGENESIS, MMTV, METHYLCHOLANTHRONE)

This dissertation addressed the hypothesis that the unique tumor specific transplantation antigens (TSTA) of chemically induced sarcomas express epitopes encoded by endogenous viral genes. TSTA from two 3-methylcholanthrene-induced, C3H/HeJ fibrosarcomas (MCA-F and MCA-D) were serologically assessed for viral epitopes in an enzyme-linked immunospecific assay (ELISA) and by immunoaffinity chromatography. Initial evidence with an anti-TSTA antiserum suggested that TSTA were associated with mouse mammary tumor virus (MMTV) peptides, but not peptides from murine leukemia virus (MuLV). TSTA extracted from MCA-F, was assessed with specific anti viral antibodies at three levels of purification for its association with MuLV peptides (gp 70 and p 15E) and MMTV peptides (gp52, gp36 and p27). The results demonstrate that purified preparations enriched for TSTA activity are devoid of MuLV epitopes, but enriched for a subset of MMTV epitopes. Immunoaffinity supports constructed with anti-MMTV antibodies retained TSTA from partially purified MCA-F or MCA-D extracts. Immunoaffinity chromatography with antibodies against individual MMTV peptides demonstrated that the MCA-F TSTA was specifically retained by anti-gp36 and anti-p27 supports, but not by anti-gp52 supports nor a support made with bovine serum albumin. Analysis of the affinity purified TSTA preparations by HPGPC and SDS-PAGE revealed only a few components. Application of the anti-gp36 and anti-p27 retained materials to HPGPC and subsequent in vivo analysis demonstrated that the TSTA migrated in a low and a high molecular weight region. These results suggest that TSTA specificity in C3H/HeJ mice, results from MMTV recombinant proteins. ^

Variable phenotypic expressivity in inbred retinal degeneration mouse lines: A comparative study of C3H/HeOu and FVB/N rd1 mice

PURPOSE Recent advances in optogenetics and gene therapy have led to promising new treatment strategies for blindness caused by retinal photoreceptor loss. Preclinical studies often rely on the retinal degeneration 1 (rd1 or Pde6b(rd1)) retinitis pigmentosa (RP) mouse model. The rd1 founder mutation is present in more than 100 actively used mouse lines. Since secondary genetic traits are well-known to modify the phenotypic progression of photoreceptor degeneration in animal models and human patients with RP, negligence of the genetic background in the rd1 mouse model is unwarranted. Moreover, the success of various potential therapies, including optogenetic gene therapy and prosthetic implants, depends on the progress of retinal degeneration, which might differ between rd1 mice. To examine the prospect of phenotypic expressivity in the rd1 mouse model, we compared the progress of retinal degeneration in two common rd1 lines, C3H/HeOu and FVB/N. METHODS We followed retinal degeneration over 24 weeks in FVB/N, C3H/HeOu, and congenic Pde6b(+) seeing mouse lines, using a range of experimental techniques including extracellular recordings from retinal ganglion cells, PCR quantification of cone opsin and Pde6b transcripts, in vivo flash electroretinogram (ERG), and behavioral optokinetic reflex (OKR) recordings. RESULTS We demonstrated a substantial difference in the speed of retinal degeneration and accompanying loss of visual function between the two rd1 lines. Photoreceptor degeneration and loss of vision were faster with an earlier onset in the FVB/N mice compared to C3H/HeOu mice, whereas the performance of the Pde6b(+) mice did not differ significantly in any of the tests. By postnatal week 4, the FVB/N mice expressed significantly less cone opsin and Pde6b mRNA and had neither ERG nor OKR responses. At 12 weeks of age, the retinal ganglion cells of the FVB/N mice had lost all light responses. In contrast, 4-week-old C3H/HeOu mice still had ERG and OKR responses, and we still recorded light responses from C3H/HeOu retinal ganglion cells until the age of 24 weeks. These results show that genetic background plays an important role in the rd1 mouse pathology. CONCLUSIONS Analogous to human RP, the mouse genetic background strongly influences the rd1 phenotype. Thus, different rd1 mouse lines may follow different timelines of retinal degeneration, making exact knowledge of genetic background imperative in all studies that use rd1 models.

Differential stress response and susceptibility to oxidative injury in alveolar macrophages from C57BL/6J and C3H/HeJ mice following oxidant exposure

Studies have demonstrated a variable response to ozone among individuals and animal species and strains. For instance, C57BL/6J mice have a greater inflammatory response to ozone exposure than C3H/HeJ mice. In these studies, I utilized these strain differences in an effort to derive a mechanistic explanation to the variable strain sensitivity to ozone exposure. Therefore, alveolar macrophages (AM) from C57BL/6J and C3H/HeJ mice were exposed in vitro to hydrogen peroxide ($\rm H\sb2O\sb2$), heat and acetyl ceramide or in vivo to ozone. Necrosis and DNA fragmentation in macrophages from the two murine strains were determined to assess cytotoxicity following these treatments. In addition, synthesis and expression of the stress proteins, stress protein 72 (SP72) and heme oxygenase (HO-1), were examined following treatments. The in vitro experiments were conducted to eliminate the possibility of in vivo confounders (i.e., differences in breathing rates in the two strains) and thus directly implicate some inherent difference between cells from the two murine strains. $\rm H\sb2O\sb2$ and heat caused greater cytotoxicity in AM from C57BL/6J than C3H/HeJ mice and DNA fragmentation was a particularly sensitive indicator of cell injury. Similarly, AM from C57BL/6J mice were more sensitive to ozone exposure than cells from C3H/HeJ mice. Exposure to either 1 or 0.4 ppm ozone caused greater cytotoxicity in macrophages from C57BL/6J mice compared to macrophages from C3H/HeJ mice. The increased sensitivity of AM to injury was associated with decreased synthesis and expression of stress proteins. AM from C57BL/6J mice synthesized and expressed significantly less stress proteins in response to heat and ozone than AM from C3H/HeJ mice. Heat treatment resulted in greater synthesis and expression of SP72. In addition, macrophages from C57BL/6J mice expressed lower amounts of HO-1 than macrophages from C3H/HeJ mice following 0.4 ppm ozone exposure. Therefore, AM from C57BL/6J mice are more susceptible to oxidative injury than AM from C3H/HeJ mice which might be due to differential expression of stress proteins in these cells. ^

Tumors induced in C3H/HeJ mice by coal tar neutral subfractions /

Mode of access: Internet.

Is serum amyloid A an endogenous TLR4 agonist?

Serum amyloid A (SAA), a classical acute-phase protein, is produced predominantly by hepatocytes in response to injury, infection, and inflammation. It has been shown that SAA primes leukocytes and induces the expression and release of proinflammatory cytokines. Here, we report that SAA induces NO production by murine peritoneal macrophages. Using specific inhibitors, we showed that NO production was dependent on inducible NO synthase thorough the activation of ERK1/2 and p38 MAPKs. Moreover, SAA activity was decreased after proteolysis but not with polymyxin B, a lipid A antagonist. Finally, we found that NO production was dependent on functional TLR4, a receptor complex associated with innate immunity. Macrophages from C3H/HeJ and C57BL/10ScCr mice lacking a functional TLR4 did not respond to SAA stimulation. In conclusion, our study makes a novel observation that SAA might be an endogenous agonist for the TLR4 complex on macrophages. The contribution of this finding in amplifying innate immunity during the inflammatory process is discussed.

Comparative analysis of dendritic cell density and total number in commonly transplanted organs: morphometric estimation in normal mice

Dendritic cells (DC) are considered to be the major cell type responsible for induction of primary immune responses. While they have been shown to play a critical role in eliciting allosensitization via the direct pathway, there is evidence that maturational and/or activational heterogeneity between DC in different donor organs may be crucial to allograft outcome. Despite such an important perceived role for DC, no accurate estimates of their number in commonly transplanted organs have been reported. Therefore, leukocytes and DC were visualized and enumerated in cryostat sections of normal mouse (C57BL/10, B10.BR, C3H) liver, heart, kidney and pancreas by immunohistochemistry (CD45 and MHC class II staining, respectively). Total immunopositive cell number and MHC class II+ cell density (C57BL/10 mice only) were estimated using established morphometric techniques - the fractionator and disector principles, respectively. Liver contained considerably more leukocytes (similar to 5-20 x 10(6)) and DC (similar to 1-3 x 10(6)) than the other organs examined (pancreas: similar to 0.6 x 10(6) and similar to 0.35 x 10(6): heart: similar to 0.8 x 10(6) and similar to 0.4 x 10(6); kidney similar to 1.2 x 10(6) and 0.65 x 10(6), respectively). In liver, DC comprised a lower proportion of all leukocytes (similar to 15-25%) than in the other parenchymal organs examined (similar to 40-60%). Comparatively, DC density in C57BL/10 mice was heart > kidney > pancreas much greater than liver (similar to 6.6 x 10(6), 5 x 10(6), 4.5 x 10(6) and 1.1 x 10(6) cells/cm(3), respectively). When compared to previously published data on allograft survival, the results indicate that the absolute number of MHC class II+ DC present in a donor organ is a poor predictor of graft outcome. Survival of solid organ allografts is more closely related to the density of the donor DC network within the graft. (C) 2000 Elsevier Science B.V. All rights reserved.

Closely related Symbiodinium spp. differ in relative dominance in coral reef host communities across environmental, latitudinal and biogeographic gradients

The diversity and community structures of symbiotic dinoflagellates are described from reef invertebrates in southern and central provinces of the Great Barrier Reef (GBR), Australia, and Zamami Island, Okinawa, Japan. The symbiont assemblages from region to region were dominated by Clade C Symbiodinium spp. and consisted of numerous host-specific and/or rare types (specialists), and several types common to many hosts (generalists). Prevalence in the host community among certain host-generalist symbionts differed between inshore and offshore environments, across latitudinal (central versus southern GBR) gradients, and over wide geographic ranges (GBR versus Okinawa). One particular symbiont (C3h) from the GBR had a dramatic shift in dominance. Its prevalence ranged from being extremely rare, or absent on high-latitude reefs to dominating the scleractinian diversity on a mid-latitude inshore reef. These changes occurred among coral fauna whose larvae must acquire symbionts from environmental sources (horizontal symbiont acquisition). Such differences did not occur among 'vertical transmitters' such as Porites spp., Montipora spp. and pocilloporids (corals that directly transmit symbionts to their offspring) or among those hosts displaying 'horizontal acquisition', but that associate with specific symbionts. Most host-specialized types were found to be characteristic of a particular geographic region (i.e. Okinawa versus Central GBR versus Southern GBR). The mode of symbiont acquisition may play an important role in how symbiont composition may shift in west Pacific host communities in response to climate change. There is no indication that recent episodes of mass bleaching have provoked changes in host-symbiont combinations from the central GBR.