Comparative studies between nude and scid mice on the growth and metastatic behavior of xenografted human tumors

The growth and metastatic behavior of three human tumor cell lines and a human colon carcinoma previously passagedin vivo were compared between nude mice and scid mice after xenotransplantation. The three human tumor lines included a bladder carcinoma (T24B), a melanoma (RPMI 7931) and alacZ gene-transduced breast cancer (MDA-MB-435 BAG). ThelacZ gene codes for -galactosidase, which can be stained blue with chromogenic substrate X-gal, thus allowing the highly sensitive detection and quantitative examination of human cancer metastasis in host mice. Adult (7–14 weeks) NMRI nude and C.B-17 SCID mice were inoculated with 0.5–5 × 10⁶ tumor cells s.c. Comparable take rate, latent period and growth rate of implanted tumors were observed in nude and scid mice for each of the cell lines tested. At the time of autopsy, which varied from 6 to 11 weeks after inoculation, a significantly higher incidence of spontaneous lung metastasis was discovered in scid mice (96%) than in age-matched nude mice (27%, totalP < 0.001).In vitro assays for NK cell-mediated cytotoxicity revealed no significant differences between the two strains of mice. Our results suggest that nude and scid mice are equally suitable for propagating human tumors. However, the metastatic capacity of human tumor cells appears to be better expressed in scid mice. Scid mice may therefore provide an advantageous model for the study of human tumor metastasis.     

快速老化系小鼠与昆明系小鼠AD相关指标的比较

目的： 观察6月龄的快速老化系SAM-P/8、SAM-R/1小鼠与昆明系小鼠的AD相关指标的变化。方法： 取健康（20±5）g 6月龄SAM-P/8小鼠、SAM-R/1小鼠和昆明系小鼠各14只，雌雄各半，随机分成：SAM-P/8小鼠（AD疾病模型小鼠）、SAM-R/1小鼠对照组和昆明系小鼠对照组，观察上述3组小鼠行为学、神经生化、超微结构、基因表达情况。结果： 6月龄SAM-P/8小鼠1-4d学习成绩、第5 d记忆成绩低于6月龄SMA-R小鼠和昆明系小鼠（P<0.05），真性胆碱酯酶活性则高于6月龄SMA-R/1小鼠和昆明系小鼠（P<0.05）；SAM-P/8小鼠海马神经元超微结构显示明显纤维化，而SAM-R/1小鼠和昆明系小鼠无明显纤维化；SAM-P/8小鼠脑神经细胞的凋亡相关基因表达有明显上调达2倍以上，而SAM-R/1小鼠和昆明系小鼠则未见这些基因有明显上调。SAM-R/1小鼠和昆明系小鼠比较，除基因表达略有差异之外，其它指标无明显差异。结论： 6月龄SAM-P/8小鼠在很多方面已经具备了AD自然发病模型典型特征。而用于正常对照的6月龄SAM-R/1与昆明系小鼠的行为学、TchE活性、超微结构则无显著差异；凋亡相关基因表达差异不明显，而部分基因表达则有一定差异。     

Mouse models for studies of HLA-G functions in basic science and pre-clinical research

HLA-G was described originally as a tolerogenic molecule that allows the semiallogeneic fetus to escape from recognition by the maternal immune response.This review will discuss different steps in the study of HLA-G expression and functions in vivo, starting with analyses of expression of the HLA-G gene and its receptors in transgenic mice, and continuing with applications of HLA-G and its receptors in prevention of allograft rejection, transplantation tolerance, and controlling the development of infection. Humanized mouse models have been discussed for developing in vivo studies of HLA-G in physiological and pathological conditions. Collectively, animal models provide an opportunity to evaluate the importance of the interaction between HLA-G and its receptors in terms of its ability to regulate immune responses during maternal-fetal tolerance, survival of allografts, tumor-escape mechanisms, and development of infections when both HLA-G and its receptors are expressed. In addition, in vivo studies on HLA-G also offer novel approaches to achieve a reproducible transplantation tolerance and to develop personalized medicine to prevent allograft rejection.     

Event-related oscillations as risk markers in genetic mouse models of high alcohol preference

Mouse models have been developed to simulate several relevant human traits associated with alcohol use and dependence. However, the neurophysiological substrates regulating these traits remain to be completely elucidated. We have previously demonstrated that differences in the event-related potential (ERP) responses can be found that distinguish high-alcohol preferring from low alcohol preferring mice that resemble differences seen in human studies of individuals with high and low risk for alcohol dependence. Recently, evidence of genes that affect event-related oscillations (EROs) and the risk for alcohol dependence has emerged, however, to date EROs have not been evaluated in genetic mouse models of high and low alcohol preference. Therefore, the objective of the present study was to characterize EROs in mouse models of high (C57BL/6 [B6] and high alcohol preference 1 [HAP-1] mice) and low (DBA/2J [D2] and low alcohol preference-1 [LAP-1] mice) alcohol preference. A time-frequency representation method was used to determine delta, theta and alpha/beta ERO energy and the degree of phase variation in these mouse models. The present results suggest that the decrease in P3 amplitudes previously shown in B6 mice, compared to D2 mice, is related to reductions in evoked delta ERO energy and delta and theta phase locking. In contrast, the increase in P1 amplitudes reported in HAP-1 mice, compared to LAP-1 mice, is associated with increases in evoked theta ERO energy. These studies suggest that differences in delta and theta ERO measures in mice mirror changes observed between groups at high- and low-risk for alcoholism where changes in EROs were found to be more significant than group differences in P3 amplitudes, further suggesting that ERO measures are more stable endophenotypes in the study of alcohol dependence. Further studies are needed to determine the relationship between expression of these neurophysiological endophenotypes and the genetic profile of these mouse models.     

Unusual cytotoxic activities of thymus-independent, self-antigen-specific CD8(+) T cells

We compared the cytotoxic activities of thymus-dependent and thymus-independent CD8(+) T cells. Thymus-dependent CD8(+) T cells, which are foreign antigen specific, acquired cytotoxic activity to tumor cells with a basal dose of the antigen peptides and to hybridoma cells expressing anti-TCR mAb only after differentiation into effector cytotoxic T lymphocytes (CTL). In contrast, thymus-independent CD8(+) T cells, which have been shown to be self-antigen specific, never showed cytotoxic activity to the target cells with a basal dose of the self-antigen peptide, while they could lyse hybridoma cells expressing anti-TCR mAb even without prior antigenic stimulation. Furthermore, the ex vivo cytotoxic activity of thymus-independent CD8(+) T cells was also observed against the target cells with high doses of the antigen peptides, which were not lysed by freshly isolated thymus-dependent CD8(+) T cells. Thus it is revealed that thymus-independent, self-antigen-specific CD8(+) T cells already acquire mature CTL functions in situ but have an increased threshold of TCR-mediated signaling for activation. These differences in cytotoxic activities between thymus-dependent and thymus-independent CD8(+) T cells suggest distinct roles of the two subsets of CD8(+) T cells in vivo.     

Measurement of affinity in serum samples of antigen-free,germ-free and conventional mice after hyperimmunization with 2,4-dinitrophenyl keyhole limpet hemocyanin,using surface plasmon resonance

We previously investigated the primary and secondary responses and hyperimmunization to the T cell-dependent antigen 2,4-dinitrophenyl keyhole limpet hemocyanin (DNP-KLH) in antigen-free (AF), germ-free (GF) and conventional (CV) mice. Both the absolute and relative numbers of DNP-specific IgG-secreting cells in the spleen of AF mice were considerably higher compared to GF and CV mice, especially after hyperimmunization. In the present study we measured the total and DNP-specific IgG concentration in the sera of these hyperimmunized mice using a sensitive sandwich enzyme-linked immunosorbent assay. With respect to the total IgG concentration before and after hyperimmunization, the AF mice showed an almost 13-fold increase after boosting with the antigen; the GF mice showed an approximately 8-fold increase. A slight but non-significant increase was observed in the CV mice. The total as well as the DNP-specific IgG levels in the AF-immunized mice were 2-fold and 5-fold higher compared to GF and CV mice, respectively. With the use of Surface Plasmon Resonance instrumentation (BIAcore^TM, Pharmacia, Uppsala, Sweden) we obtained mean binding affinities (K_A) of the polyclonal samples of the three groups of hyperimmunized mice. IgA and IgM samples displayed low affinity for DNP-lysine. The AF mice displayed the highest K_A value among IgG antibodies, followed by GF mice, while CV mice showed a 3-fold lower K_A compared to AF mice. These differences were mainly determined by the dissociation rate constant (k_diss), since no significant changes were observed in the association rate constant (k_ass). Furthermore, the sera of the CV mice have a lower percentage of high-affinity antibodies compared to GF and AF mice. These results suggest that besides a higher overall binding affinity seen in AF mice, and to a lesser extent in GF mice, the relative contribution of high-affinity IgG is greater in AF mice compared to CV mice.     

Effects of variations in copulatory behavior on pregnancy in two species of Peromyscus

Stimulation requirements for the initiation of pregnancy were studied in cotton mice, Peromyscus gossypinus, and white-footed mice, P. leucopus. Mating to satiety rather than for one ejaculatory series significantly increased the per cent of P. gossypinus females pregnant (63% vs 0%). Among females mated to satiety, those which became pregnant received significantly more copulations than those which did not. While no P. leucopus female mated for one ejaculatory series became pregnant, the increase in the probability of pregnancy following tests continued to satiety (or satiety plus overnight) was not significant, as just 20% of females in the satiety groups became pregnant. The multiple ejaculation pattern in these species appears to be an integral part of pregnancy initiation.     

小家鼠群体基因组连锁不平衡研究

模式动物小鼠是复杂性状相关疾病遗传研究的重要资源.连锁不平衡(linkage disequilib-rium,LD)是群体基因组遗传的重要信息.如果群体LD程度高,相关连锁区段大,有助于用少量遗传位标来对目标基因进行初步定位;反之,如果群体LD程度低,相关连锁区段小,则利用高密度的遗传位标可以对目标基因进行精细定位.本文介绍了实验小鼠群体和野生小鼠群体相关的LD、与LD相关的部分遗传参数以及利用LD进行相关基因定位研究.并提示实验小鼠和野生小鼠各具优势,都是复杂性状基因定位的重要遗传资源.     

Current advances in humanized mouse models

Humanized mouse models that have received human cells or tissue transplants are extremely useful in basic and applied human disease research. Highly immunodeficient mice, which do not reject xenografts and support cell and tissue differentiation and growth, are indispensable for generating additional appropriate models. Since the early 2000s, a series of immunodeficient mice appropriate for generating humanized mice has been successively developed by introducing the IL-2Rγ^null gene (e.g., NOD/SCID/γc^null and Rag2^nullγc^null mice). These strains show not only a high rate of human cell engraftment, but also generate well-differentiated multilineage human hematopoietic cells after human hematopoietic stem cell (HSC) transplantation. These humanized mice facilitate the analysis of human hematology and immunology in vivo. However, human hematopoietic cells developed from HSCs are not always phenotypically and functionally identical to those in humans. More recently, a new series of immunodeficient mice compensates for these disadvantages. These mice were generated by genetically introducing human cytokine genes into NOD/SCID/γc^null and Rag2^nullγc^null mice. In this review, we describe the current knowledge of human hematopoietic cells developed in these mice. Various human disease mouse models using these humanized mice are summarized.     

Suppression of experimental lupus nephritis by aberrant expression of the soluble E-selectin gene

Circulating leukocytes, particularly neutrophils and monocytes, are important effector cells in the induction of many forms of glomerulonephritis. Adhesion molecules, especially selectins, are also thought to be critical for the development of this disease. We examined the possible suppressive effect of soluble E-selectin on the development of experimental lupus nephritis induced by the injection of a hybridoma clone (2B11.3) derived from an MRL/MpJ-lpr/lpr lupus mouse. This clone produces IgG3 antibodies that induce severe proliferative glomerulonephritis resembling lupus nephritis when injected into normal mice. Transgenic mice with a soluble E-selectin gene were injected intraperitoneally with the hybridoma cells and histopathologically examined on day 15. As a result, the development of glomerulonephritis was significantly suppressed. This suppression was characterized by fewer inflammatory cell infiltrates, compared with non-transgenic litter mates, despite the fact that there were no remarkable differences in immunoglobulin deposits or expression of E-selectin between the two groups. These findings suggest that by controlling inflammatory cell infiltration, soluble E-selectin plays a preventative role in the development of a particular type of lupus nephritis.     

Passive transfer of immunity of Mycobacterium avium in susceptible and resistant strains of mice.

Naturally susceptible mice (C57BL/6) infected with M. avium (strain Weybridge) developed a population of splenic T cells which, on transfer to syngeneic recipient mice, conferred significant protection against a subsequent challenge inoculum of M. avium. Similar T cells from naturally resistant mice (A/J) did not protect syngeneic recipient mice. Growth of M. avium in donor mice only occurred in the C57BL/6 strain. Replication of M. avium in donor mice was necessary for the development of protective T cells. High numbers of killed mycobacterium did not induce immune T cells. In addition, A/J mice inoculated with increasing numbers of viable M. avium (which still did not replicate) failed to develop protective T lymphocytes. Further studies indicated that no protective T cells were present in the M. avium-infected A/J mouse, although evidence for non-specific immunity in these mice was obtained. In addition, BCG (which grows progressively in A/J mice) stimulated a population of splenic T cells which protected recipient mice from subsequent infection with M. tuberculosis.     

Immune responsiveness in Mycobacterium avium-infected mice: changes in the proportion of T cell subsets and antibody production during the course of infection.

The C57Bl/6 susceptible (Bcgs) and its resistant (Bcgr) congenic mouse, previously developed by retrogressive backcrossing, were infected with 1 x 10(6) colony-forming units (CFU) of Mycobacterium avium and bacterial growth and their immune responses during the early and prolonged periods of infection were examined. There was a high proliferation in the liver and spleen of Bcgs mice, whereas no proliferation was observed in the Bcgr mice. Similarly, the sizes and weights of these organs were much higher than those of their Bcgr counterparts. The size and number of granulomas in Bcgs were also found to be higher than those of Bcgr. The CD3+ and CD4+ subsets increased dramatically in both mice during the early stage of infection. However, in the later phase of the infection, these populations decreased dramatically in Bcgs mice, but not in Bcgr mice, resulting in a depression in cell-mediated immune responses. No significant decrease in cell-mediated immune responses was observed in Bcgr mice even after prolonged infection. ELISA was performed to determine the antibody levels in both mice, and it was found that serum IgG and IgM levels in Bcgs were comparatively higher than those in Bcgr mice throughout the period of infection. The Bcg gene therefore may have an important role in the maintenance of resistance not only in the early phase but also in the later phase of Myco. avium infection.     

Carnosine-Induced Changes in the Development of Spermatogenic Epithelial Cells in Senescence Accelerated SAM Mice

Carnosine significantly increased the number of spermatogonia and Sertoli cells in mice prone (SAMP1) and resistant (SAMR1) to accelerated aging and appreciably reduced cell yield in meiosis and spermiogenesis in SAMP1 mice. In experimental SAMP1 mice catastrophic changes in the number of gametes were paralleled by intensive degradation of the spermatogenic epithelium. In SAMR1 mice treated with carnosine highly ordered spermatogenic structure was preserved. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 8, pp. 206–209, August, 2005     

Analysis of genomic homology of murine gammaherpesvirus (MHV)-72 to MHV-68 and impact of MHV-72 on the survival and tumorigenesis in the MHV-72-infected CB17 scid/scid and CB17+/+ mice

Murine gammaherpesvirus (MHV)-68-infected mice are well-known as models for Epstein-Barr virus (EBV)-related lymphoproliferative diseases. MHV-72 may be a relative of MHV-68, but any genetic comparison between the two (except for the M7 gene) has never been reported. The genetic compositions of MHV-72 and MHV-68 were compared and the pathology of MHV-72 infection studied in CB-17 severe combined immunodeficiency (scid/scid; SCID) and CB17 wild-type (CB17+/+) mice. The MHV-72 DNA sequence was almost identical to MHV-68 except for approximately 7000 bp corresponding to the MHV-68 M1-M3 genes. Twenty-seven of 30 MHV-72-infected SCID mice (90%) died from generalized infection with intranuclear viral inclusions for approximately 1 month, while MHV-72-infected CB17+/+ mice recovered from acute infection. Long observation and pathological study of 68 MHV-72-infected mice for up to 24 months revealed that the survival rate (29.4%) and survival time (21.3 months) of MHV-72-infected CB17+/+ mice were significantly lower (P = 0.0127) and shorter (P = 0.0065) than those of the controls (61.1% and 22.9 months), respectively. The malignancy development rate (60.3%) of the infected CB17+/+ mice was also significantly higher (P = 0.004) than those of the controls (22.2%). However, no MHV-72 DNA was detected in the tumors of infected mice. MHV-72 may have some tumor-promoting effects but the tumorigenesis in infected CB17+/+ mice is different from EBV-associated tumors.     

Ontogeny of behavior in mice selected for large size

Development of 13 reflex responses and behavioral components of mice from the Goodale Giant inbred strain (G/Gw) was compared to that of a sample of 61 pups from a random-bred strain. Significant differences were observed between groups for several responses, but the direction of these differences was not consistent. Effects of rapid growth and increased size in G/Gw mice did not directly affect behavioral maturation.     

p110δ突变失活的ApcMin/+结直肠癌癌前病变小鼠模型的建立

 目的：建立p110δ突变失活的ApcMin/+结直肠癌癌前病变小鼠模型,为研究p110δ在小鼠结直肠癌癌前病变中的作用提供实验模型。方法：将C57BL/6J背景的ApcMin/+结直肠癌癌前病变小鼠与p110δ突变失活小鼠（p110δD910A/D910A）进行杂交建系,通过PCR技术鉴定子代小鼠基因型,获得p110δ突变失活的ApcMin/+小鼠。对适龄小鼠进行肠道取材,亚甲蓝染色后,观察肠道结构,对腺瘤和微腺瘤进行统计。肠道组织进行石蜡包埋、切片,做HE染色进行进一步观察。结果：获得p110δ突变失活的ApcMin/+杂交鼠（ApcMin/+;p110δD910A/D910A）并得以稳定传代。ApcMin/+;p110δD910A/D910A杂交小鼠的肠道组织中,腺瘤数目和体积比ApcMin/+结直肠癌癌前病变小鼠均有减少。结论：成功建立p110δ突变失活的ApcMin/+结直肠癌癌前病变小鼠模型,并得到小鼠肠道肿瘤的初步表型,为进一步研究p110δ在肠道肿瘤发生发展中的作用提供重要的工具动物。     

Role of RANTES in the development of autoimmune tissue injuries in MRL-Fas lpr mice

MRL-Fas lpr mice spontaneously develop a severe autoimmune disease closely resembling human SLE. To investigate the possible role of RANTES in autoimmune tissue injuries, we have constructed RANTES-deficient MRL-Fas lpr mice by gene targeting. In the RANTES-deficient mice, axillary lymph nodes were significantly reduced in size compared with those of RANTES-intact mice. Flow cytometric analysis revealed that double-negative (DN) T cells were significantly reduced. Image analyzer showed that cell-infiltrated areas in peribronchial lesions were decreased in the lung of RANTES-deficient MRL-Fas lpr mice. Furthermore, we detected continuous expression of RANTES mRNA in the lung of MRL-Fas lpr mice. In contrast, the degree of histological renal injuries and survival rate was similar in both genotypes. We speculate that RANTES is involved in the development of peribronchial pulmonary lesions in MRL-Fas lpr mice. Further studies using RANTES-deficient mice might contribute to the elucidation of the role of RANTES in autoimmune tissue injuries.     

The NOD Mouse as a Model of SLE

In addition to developing a high incidence of type 1 diabetes caused by a specific autoimmune response against pancreatic β cells in the islets of Langerhans, NOD mice also demonstrate spontaneous autoimmunity to other targets including the thymus, adrenal gland, salivary glands, thyroid, testis, nuclear components and red blood cells. Moreover, treatment of pre-diabetic NOD mice with an intravenous dose of heat killed Mycobacterium bovis (M. bovis; bacillus Calmette-Guerin (BCG)) protects them from developing type 1 diabetes, but instead precipitates an autoimmune rheumatic disease similar to systemic lupus erythematosus (SLE), characterised by accelerated and increased incidence of haemolytic anaemia (HA), anti-nuclear autoantibody (ANA) production, exacerbation of sialadenitis, and the appearance of immune complex-mediated glomerulonephritis (GN). The reciprocal switching between the two phenotypes by a single environmental trigger (mycobacterial exposure) raised the possibility that genetic susceptibility for type 1 diabetes and SLE may be conferred by a single collection of genes in the NOD mouse. This review will focus on the genetic components predisposing NOD mice to SLE induced by BCG treatment and compare them to previously determined diabetes susceptibility genes in this strain and SLE susceptibility genes in the BXSB, MRL and the New Zealand mouse strains     

CYP2E1 inhibition enhances mallory body formation

Mallory body (MB) formation is a complex phenomenon seen in chronic liver disease. CYP2E1 may play a role in preventing MB formation since it is involved in the elimination of toxic drugs and chemicals. When mice were fed with diethyl-1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate (DDC) for 10 weeks, Mallory bodies (MBs) developed in the liver at the end of this period. When DDC feeding was combined with CMZ (an efficient in vivo CYP2E1 inhibitor), more MBs formed compared to DDC feeding alone. DDC was shown to be a suicide inhibitor of CYP2E1. The level of CYP2E1 protein in the liver was further reduced by the DDC and CMZ treatment when measured by Western blot. To test whether CYP2E1 reduced MB formation, CYP2E1 knockout mice and CYP2E1 overexpressed mice were fed with DDC or DDC and CMZ for 10 weeks. MB formation increased markedly in the liver of CYP2E1 knockout mice when fed with DDC only. CYP2E1 overexpressed mice showed an increase in MB formation when the mice were fed with the combination of DDC and CMZ where the amount of CYP2E1 was reduced to levels seen in wild type mice. It was concluded that CYP2E1 inhibits MB formation by increasing the rate of elimination of DDC and/or its toxic intermediates.