Effector mechanisms of syngeneic anti-tumour responses in mice. II. Cytotoxic T lymphocytes mediate neutralization and rejection of radiation-induced leukaemia RL male 1 in the nude mouse system.

We demonstrated the efficacy of a long-term cultured cytotoxic T-lymphocyte line, CTLL-D4, on tumour growth inhibition using athymic nude mice as recipients. CTLL-D4, specific for a unique surface determinant on a radiation-induced leukaemia RL male 1 of BALB/c origin, was obtained from the limiting dilution culture of MLTC cells performed between spleen cells of a CB6F1-nu/+ mouse immunized in vivo and RL male 1 stimulator cells, and cultured for several months in the absence of added TCGF as described in our preceding paper (Kuribayashi, 1985). The specific inhibition of tumour growth by CTLL-D4 was demonstrated both in Winn-type neutralization assay and in systemic transfer experiments. A subcutaneous inoculation of the mixture of CTLL-D4 and RL male 1 cells resulted in the complete inhibition of tumour growth, even at the effector to tumour cell ratio of 1:1, whereas non-cytolytic D4f, which was self-Ia antigen(s)-reactive, composed entirely of Lyt-1+23- T cells and derived originally from CTLL-D4 but completely lost its cytotoxic activity during culture with the irradiated syngeneic feeder cells alone, had no inhibitory effect at all. In the adoptive transfer studies, the subcutaneously established tumours were rejected by the single i.v. transfer of 2 X 10(7) CTLL-D4 cells into CB6F1-nu/nu mice. However, D4f was ineffective again in this systemic transfer system. When the effect of CTLL-D4 cells on tumour rejection in vivo was compared to that of non-cultured spleen cells hyperimmunized with RL male 1 cells, the former exhibited more rapid rejection in nude mice after i.v. transfer than the latter did, suggesting that CTLL-D4 cells also attack the tumour cells much more effectively as effectors in vivo. Thus, it is conceivable that CTLs are mainly involved in tumour rejection in this adoptive transfer system using RL male 1 tumour cells and athymic nude mice.     

The postnatal development of the ovary in the "nude" mouse.

The postnatal development of the ovary of the heterozygous nude (nu/+) mouse with the genetic background BALB/c is very similar--if not identical-- to that of other mouse strains. As other BALB/c mice, the nu/+ females become sexually mature during the 5th week post partum (p.p.). At this age the ovaries corpora lutea at various stages of differentiation. In the ovaries of newborn and 1 week-old homozygous (nu/nu) mice, the differentiation of oocytes into primary and secondary follicles is delayed. In the third postnatal week, the ovaries of homozygous females contain more atretic follicles than those of their heterozygous littermates. This increased degeneration of follicles may account for the greater mass of secondary interstitial tissue, which is observed in the ovaries of adult nu/nu females. In nine out of the 5 to 7 week-old nu/nu mice studied, the ovaries contained no-/or only very few corpora lutea. Thus in homozygous nude females, the onset of sexual maturity is delayed. This ovarial immaturity may persist throughout life. In other animals development may become normal. In addition to the impaired postnatal development of the ovary, unspecific inflammation of the uterine wall (endo- and/or myometritis) was detected in 47% of nu/nu animals older than five weeks. No direct correlation was, however, found between the delay of sexual maturation and the inflammatory changes in the uterus as many of the animals with an endo- or myometritis possessed mature ovaries. The low fertility of the female homozygous "nude" mouse seems, therefore, to be caused not only by an impaired differentiation of the ovary but also by inflammatory processes in the uterus.     

Human monoclonal antibody to tumor-associated ganglioside GD2: suppressed growth of human melanoma in nude mice

Human IgM kappa monoclonal antibody (anti-GD2) to a tumor antigen, ganglioside GD2, has been produced by Epstein-Barr virus-transformed human B lymphoblasts. In the present study, we demonstrated the anti-tumor effects of passively administered anti-GD2 against an ascites-form human melanoma cell line, M14-A, transplanted into athymic nude mice. M14-A expresses GD2 in vivo. Cells (5 X 10(5) were inoculated intraperitoneally (i.p.) or subcutaneously (s.c.) into CD-1 nude mice that had received i.p. injections of 200 micrograms anti-GD2 and rabbit complement. Significant tumor-free intervals were observed in the treated mice (P less than 0.005) for i.p. tumors and P less than 0.025 for s.c. tumors). M14-A formed well-vascularized s.c. tumors if injected into young nude mice. Three-wk-old CD-1 nude mice bearing 2-3 mm M14-A s.c. tumor nodules were treated i.p. with anti-GD2 and rabbit complement. Tumor growth was delayed for 25 days. On day 15, treated tumors were 20% the size of control tumors. Because most biopsied or autopsied melanomas express GD2, and because patients with melanoma produce autoantibodies to GD2, the results in this study may provide important information for future passive immunization with human monoclonal antibody and for active specific immunization with GD2 antigen.     

Immunohistochemical evidence for mesothelial origin of paratesticular adenomatoid tumour

AIMS: To investigate the histogenesis of paratesticular adenomatoid tumour by use of immunohistochemical markers for a variety of carcinomas and mesothelioma. METHODS AND RESULTS: Immunohistochemical staining of sections from 12 cases of paratesticular adenomatoid tumour was undertaken using primary antibodies to antigens expressed by benign epithelial cells and carcinoma (cytokeratin AE1/AE3, cytokeratin 34ssE12, epithelial membrane antigen, MOC-31, Ber-EP4, CEA, B72.3, LEA.135, Leu M1), stromal and vascular markers (vimentin, CD34, factor VIII), and mesothelioma-associated antigens (thrombomodulin, HBME-1, OC 125) and p53 protein. There was absence of immunohistochemical expression of epithelial/carcinoma markers MOC-31, Ber-EP4, CEA, B72.3, LEA.135, Leu M1 and to factor VIII and CD34. All tumours expressed cytokeratin AE1/AE3, epithelial membrane antigen and vimentin, with weak expression of cytokeratin 34ssE12 in 25% of tumours. Each tumour showed expression of thrombomodulin, HBME-1 and OC 125 in a membranous distribution. p53 protein expression was not detected. CONCLUSIONS: The immunohistochemical profile of paratesticular adenomatoid tumour is strongly supportive of a mesothelial cell origin.     

Transplantable mouse 16/C mammary adenocarcinoma as a model in experimental cancer therapy. I. Kinetics of growth and spread

Introduction of transplantable animal tumours has enabled the development of different model systems in which the site and type of tumour growth depends on the selection of suitable route for cells inoculation. Manipulation of the inoculation route of 16/C mammary adenocarcinoma results in local tumour growth either subcutaneous (s.c.), intramuscular (i.m.), intraperitoneal (i.p.) or intrasplenical (i.spl.) and development of metastases in lungs, lymph nodes, and liver. Exponential model of s.c. growth of the tumour was estimated and doubling time value calculated (3, 64 days). Correlation between the presence of tumour cells in lungs and advancement of s.c. growing tumours was found. Usefulness of 16/C adenocarcinoma as a model for experimental therapy is discussed.     

Growth of transplantable melanoma and leukaemia and prevention of virus-induced leukaemia in long lived radiation chimeras constructed with unmanipulated bone marrow.

Haemopoietic radiation chimeras across the H-2 barrier (BALB/c----C57Bl/6; H-2d----H-2b chimeras and vice versa) have been studied for their capacity to suppress the growth, or to reject, transplantable B16 melanotic melanoma and radiation leukaemia virus-induced, transplantable leukaemia. Also, radiation leukaemia virus (RadLV) obtained from the thymus of leukaemic C57Bl/6 mice was injected i.p. into established chimeras (H-2d----H-2b). As expected, long lived, graft versus host disease free allogeneic chimeras constructed with intact bone marrow were unable to reject the tumours both when recipients were BALB/c----C57Bl/6 or C57Bl/6----BALB/c chimeras. However, also inoculation of a large number of immunocompetent cells from normal BALB/c mice into BALB/c----C57Bl/6 chimeras, failed to promote a rejection of the tumours. On the contrary, the same amount of syngeneic (BALB/c) immunocompetent cells prevented growth of melanoma when transferred into athymic nude BALB/c mice, while the tumour grew unimpaired in untreated athymic nude BALB/c mice. The same type of H-2d----H-2b chimeras displayed complete resistance to inculation of leukaemogenic H-2b restricted RadLV while all H-2b----H-2b, syngeneically reconstituted mice developed disseminated leukaemia. These findings demonstrate that: (a) a powerful suppressive principle operates in the chimeras which does not allow effector function and anti-tumour activity of passively transferred normal, mature T cells from resistant BALB/c mice. Thus, no H-2 restriction of donor T cells can be advocated for suppression of anti-tumour effector functions in the chimeras. (b) New donor (BALB/c, H-2d) marrow character in the H-2d----H-2b chimeras prevents expression of the H-2b restricted viral activity and leukaemogenic transformation and/or proliferation.     

Experimental Yersinia enterocolitica infection in euthymic and T-cell-deficient athymic nude C57BL/6 mice: comparison of time course, histomorphology, and immune response.

To elucidate the role of T lymphocytes in primary infection with Yersinia enterocolitica, we investigated the elimination rate of this pathogen, the histomorphology of tissue lesions, and the immune responses of athymic T-cell-deficient C57BL/6 nude mice and their euthymic littermates after parenteral infection with Y. enterocolitica of serotype O:8. While a low inoculum of 3 x 10(2) Y. enterocolitica cells (about 0.01 times the median lethal dose for normal C57BL/6 mice) was cleared by normal C57BL/6 mice within 7 to 10 days, athymic nude C57BL/6 mice developed progressive infections after this inoculum, leading to death on days 20 to 25 postinfection (p.i.). While normal C57BL/6 mice experienced short-term transient infections, nude mice exhibited a biphasic, progressive infectious process. Thus, in the early phase (days 1 to 7 p.i.), a rapid influx of CD11b/18-positive cells (Mac-1 antigen) and natural killer cells was evident in the spleens and livers of the nude mice. The late phase (from day 8 p.i. onward) was characterized by a rapid progression of the infection and a further influx of CD11b/18-positive cells into the liver accompanied by an increase in bacterial counts and development of tissue lesions particularly in the liver and spleen. In normal mice, granuloma-like lesions composed of CD11b/18-, CD4-, and CD8-positive cells could be observed. However, granulomata were not found in nude mice. Yersinia-specific immunoglobulin G antibodies appeared on day 15 p.i. in the sera of normal mice, while nude mice failed to develop significant antibody titers. Adoptive transfer of Yersinia-specific T cells into athymic nude mice mediated resistance to Y. enterocolitica infection and restored both the ability of granuloma formation and the production of specific antibodies. In summary, the data presented herein strongly suggest that T lymphocytes play an essential role in the defense of C57BL/6 mice against Y. enterocolitica.     

Autoimmune diseases developed in athymic nude mice grafted with embryonic thymus of xenogeneic origin.

Reconstitution of T cell functions in athymic BALB / c nude mice was investigated after transplantation of embryonic thymus grafts under the renal capsule (TG nude mice). Thymi were obtained from mice, rats, rabbits, hamsters, guinea pigs, swine and cows. All of the grafted thymi grew and formed proper thymic structures with host CD90(+) cells. The TCRalpha beta expression pattern of the lymphocytes in the grafted thymi was quite similar to that of normal mouse thymocytes. Sufficient CD4(+) populations were observed in the peripheral lymphoid organs of all groups of TG nude mice. Plaque-forming cell assay revealed that the TG nude mice had acquired considerable helper T cell functions. Histological and serological studies, however, showed multiple organ-localized inflammatory diseases in TG nude mice of all xenogeneic thymus groups, but not with syngeneic or allogeneic thymi. The organs affected were the thyroid, the lacrimal, submandibular and sublingual glands, the eyes, stomach and ovaries. The incidence of lesions was variable depending on the species of origin of the grafted thymus. Lesions from TG nude mice were successfully transferred into naive nude mice by host CD4(+) cells. These results together suggested that the microenvironment of grafted thymi, even if xenogeneic, is able to educate host T cell precursors. However, this reconstitution of functions does not always induce tolerance to certain autoantigens, resulting in development of multiple autoimmune lesions.     

Antiangiogenic, antitumoural and antimetastatic effects of two distamycin A derivatives with anti-HIV-1 Tat activity in a Kaposi's sarcoma-like murine model

The antiangiogenic, antitumoural and antimetastatic effects of two novel sulphonic derivatives of distamycin A, PNU145156E and PNU153429, were studied in a Kaposi’s sarcoma-like tumour model obtained by injecting nude mice with cells releasing extracellular HIV-Tat protein, derived from a tumour which developed in a BK virus/tat transgenic mouse. Both PNU145156E and PNU153429 were administered intraperitoneally every fourth day for three weeks at doses of 100 or 50 mg/kg of body weight respectively, starting one day after injecting the tumour cells. Both drugs delayed tumour growth in nude mice, preventing neovascularization induced by the Tat protein. PNU153429 also significantly reduced the number and size of spontaneous tumour metastases. Both effects on tumour growth and metastases were augmented by treating simultaneously nude mice with 7.5 mg/kg of body weight of minocycline given per os daily for four weeks starting four days after injecting the tumour cells. Neither acute nor chronic toxic side-effects were observed during the life span of treated nude mice. Due to their antiangiogenic and anti-Tat effects, these drugs are promising for the treatment of Kaposi’s sarcoma in AIDS patients. This revised version was published online in July 2006 with corrections to the Cover Date.     

Characterization of two cell lines, derived from two malignant fibrous histiocytomas

We have investigated the phenotype and ultrastructure of tumour cells from two cell lines each derived from a malignant fibrous histiocytoma (MFH) as a means of studying the histogenesis of this group of tumours. The first MFH (MFH-I) was of the pleomorphic subtype, with a predominantly histiocytic appearance, the second was of the pleomorphic subtype associated with myxoid and storiform areas (MFH-II). In vitro tumour cells from both neoplasms showed aberrant growth properties. Xenografts in nude mice from both neoplasms showed a similar histology to that of the original tumour. Both tumours showed hyaluronidase sensitive alcian blue staining. Phenotypic studies of the two cell lines and of the tumour tissues demonstrated that the cells differed in the presence of collagen types I and III. They did not show evidence of histiocytic, endothelial, leiomyoblastic, rhabdomyoblastic, lipoblastic of schwannian origin. Ultrastructurally, the two cell lines were found to be different. In vitro and in xenografts the cell type of MFH-I resembled a primitive mesenchymal cell. Whereas that of MFH-II resembled a fibroblast-like cell. We concluded that the group of MFH is heterogeneous and is probably derived from more than one progenitor cell.     

The role of the spleen in the organ-specific metastasis of murine BW 5147 T lymphomas

Organ-specific metastasis of tumour cells may result from selective invasion and growth or from selective host cell responses. The present study demonstrates how selective interactions with the host affect the metastatic pattern of two murine T cell hybridoma lines, derived from the BW 5147 thymoma. Upon intravenous inoculation into syngeneic mice BW-14 cells preferentially colonize the kidneys, whereas BW-19 cells metastasize mainly to the spleen and the liver. The organ-specific behaviour of the two cell lines appears to be determined by a differential interaction with the spleen microenvironment. Inoculation of BW-14 cells into splenectomized mice results in increased liver colonization, indicating a negative effect of the spleen on BW-14 tumour development in the liver. Macrophages are likely to be involved in this inhibition, since inoculation of BW-14 cells into macrophage-depleted mice also leads to increased liver and spleen metastasis. In contrast, inoculation of BW-19 cells into splenectomized mice results in decreased liver metastasis, which indicates that the spleen exerts a stimulating effect on BW-19 cells. Macrophages also appear to be involved in this stimulation, since macrophage depletion causes a similar decrease in liver and spleen colonization. Hence components of the splenic microenvironment, probably macrophages, exert inhibiting or stimulating activities on BW-14 or BW-19 cells respectively, thereby determining the subsequent liver or kidney colonization.     

人绒毛膜癌裸鼠原位移植模型的建立

目的建立人绒毛膜癌裸鼠原位移植瘤模型。方法培养人绒毛膜癌细胞系JAR,制备JAR单细胞悬液,给5只8周龄BALB/c裸鼠经皮下注射建立皮下移植瘤模型。待裸鼠皮下成瘤后,无菌条件下取瘤组织并切成1 mm^3组织块,通过手术方式植入10只10周龄BALB/c裸鼠子宫腔内,裸鼠濒死状时4%水合氯醛(10 g/kg)腹腔注射麻醉处死,观察子宫成瘤及腹腔转移情况。解剖取子宫原位移植瘤、腹腔内转移瘤、腹腔淋巴结及其他脏器组织标本,通过组织病理学检查进行鉴定。结果10只BALB/c裸鼠中共有7只裸鼠子宫内可见移植瘤肿块形成,其中2只可同时观察到子宫移植瘤和腹膜转移瘤。在病理学形态和结构上,皮下移植瘤模型、原位移植模型和腹膜转移瘤的瘤细胞与人绒毛膜癌细胞系JAR一致。结论成功建立人绒毛膜癌JAR细胞的BALB/c裸鼠原位移植瘤模型。     

Modulation of anti-tumour immunity and the effect of bacterial endotoxin on the growth of different syngeneic tumours from small inocula in mice

Studies were undertaken to determine the influence of E. coli lipopolysaccharide (LPS) on the growth of various doses of two antigenically-distinct syngeneic murine fibrosarcomas designated H1 and H7. The 'weakly' antigenic H1 tumour injected subcutaneously (s.c.) along the abdominal wall was profoundly susceptible to the growth-potentiating effects of a single intraperitoneal (i.p.) injection of 2 micrograms LPS, administered concurrently. 'Sneaking through' effects in control mice were observed with doses of 10 and 100 H1 tumour cells. Rejection of medium-sized inocula 25 or 500 H1 tumour cells were abolished by the administration of LPS. In contrast, the 'strongly' antigenic H7 tumour did not exhibit the 'sneaking through' phenomenon and its growth was only temporarily affected by LPS. Studies were also performed to determine the effect of LPS on the kinetics of delayed-type hypersensitivity (DTH) induced by mitomycin C-treated (MCT) H1 or H7 tumour cells inoculated s.c. into the footpads of mice. The 'strongly' antigenic MCT H7 tumour cells induced consecutive waves of footpad swelling of diminishing intensity and corresponded to periods of anti-tumour resistance. The specific phase of MCT H7-induced footpad swelling, maximal at day 6, was delayed in its induction if LPS was administered concurrently with MCT H7 tumour cells. In contrast, the 'weakly' antigenic MCT H1 tumour cells induced only one specific phase of footpad swelling which was rapidly down-regulated. The induction of immunity by MCT H1 tumour cells was also delayed by the concomitant administration of LPS. Because the 'weakly' antigenic H1 tumour was unable to sustain consecutive waves of anti-tumour immunity, the delay in the expression of such immunity by LPS allowed the H1 tumour cells to multiply to eventually overwhelm a rapidly down-regulated immune response. In contrast, the incidence of tumours arising from the 'strongly' antigenic H7 tumour cells was not significantly affected in LPS-treated mice because the tumour cells which escaped the first encounter with delayed anti-tumour immunity, succumbed to subsequent waves of resistance in both normal and LPS-treated mice injected with fewer than 1 X 10(5) H7 tumour cells.     

Growth and metastatic behavior of human tumor cells implanted into nude and beige nude mice

The growth and metastatic behavior of several human tumor lines grown in adult nude mice, nude mice pretreated with antiserum against asialo GM1 glycoprotein, and beige nude mice were studied. The cell lines were all injected s.c. and i.v. A human colon carcinoma line was also injected into the spleen, and two human renal carcinoma lines were injected into renal subcapsule. All the tumor lines grew as fast or faster in adult nude mice compared with beige nude mice. There were no discernible differences in the production of experimental lung metastasis among the three groups of mice, but human colorectal carcinoma cells and human renal carcinoma cells produced more metastases in nude mice than in beige nude mice after intrasplenic or renal subcapsule injection, respectively. In vitro cytotoxicity assays confirmed that adult nude mice had high levels of natural killer (NK) cell activity whereas nude mice pretreated with anti-asialo GM1 serum and beige nude mice did not. The in vitro NK cell activity of nude mice was demonstrable against mouse lymphoma cells but not against human leukemia cells which were sensitive to lysis by human NK cells. These results suggest that the implantation of human tumor cells into beige nude mice, which are deficient in NK cell activity does not provide an advantageous model for the study of growth and metastasis of human neoplasms.Abbreviations NK natural killer - HCC human colon carcinoma - HRCC human renal cell carcinoma - anti-asGM1 anti-asialo GM1 - i.s. intrasplenic - RSC renal subcapsule - HBSS Ca²⁺- and Mg²⁺-free Hanks' balanced salt solution     

Fatty change of the liver microenvironment influences the metastatic potential of colorectal cancer

Fatty liver is the most common cause of liver disease, and its prevalence has been increasing globally. Colorectal cancer (CRC) accounts for approximately 10% of all cancers and metastasizes most commonly to the liver. Paget's ‘Seed and Soil’ theory of metastasis proposed that the secondary growth of cancer cells is dependent on the distal organ microenvironment. This implies that the risk of metastasis may change due to changes in the microenvironment of target organs. However, the association between steatosis, fatty change in the liver microenvironment, and liver metastasis has not been clarified. Here, we induced fatty liver conditions in BALB/c mice using a choline‐deficient high‐fat diet with 0.1% methionine (CDAHFD) and then injected the CT26 cells to produce experimental metastasis. The number of metastatic tumours was significantly increased in mice with severe fatty liver as compared to control mice. The average size of metastatic tumours was smaller in mice with moderate fatty liver than in control mice. The stromal components, including cancer‐associated fibroblasts, tumour‐associated macrophages and tumour‐infiltrating lymphocytes, were also examined. Metastatic tumours in fatty liver showed invasive growth patterns without a fibrotic capsule. Compared to control groups, the polarization of macrophages and subtypes of tumour‐infiltrating lymphocytes differed depending on the extent of fatty liver progression. These results indicated that fatty changes in the liver influenced liver metastasis of CRC. Although moderate fatty changes suppress the growth of metastatic tumours in the liver, a severe fatty microenvironment may promote invasion and metastasis through alteration of the tumour microenvironment (TME).     

Scid小鼠免疫重建及T、B和NK细胞对CNE－2Z－H_5移植瘤生长的影响

采用近系淋巴细胞输入或移植胸腺重建Ｓｃｉｄ小鼠免疫功能，以环磷酰胺抑制ＢＡＬＢ／Ｃ裸鼠ＮＫ功能，然后移植ＣＮＥ－２Ｚ－Ｈ＿５。移植瘤生长速度及瘤重依次为：Ｓｃｉｄ小鼠组→ＮＫ功能抑制组→ＢＡＬＢ／Ｃ裸鼠组→免疫重建组；淋巴细胞输入组６／６例、胸腺移植组１／３例于荷瘤２２天内移植瘤完全消退。表明免疫重建成功，有较强抗瘤效应。     

介导RA538与反义c-myc腺病毒对肿瘤细胞的作用及其分子机理

目的　比较全反式维甲酸诱导基因 RA5 38及反义 c- myc对人胃癌细胞的生物学特性 ,并探讨其作用的分子机理。方法　采用细胞生长曲线、DNA梯度降解试验、原位末端标记、流式细胞仪、逆转录 -聚合酶链反应、蛋白质印迹分析、裸鼠致瘤性、裸鼠皮下移植瘤模型实验等方法 ,对 RA5 38、反义 c- myc重组腺病毒在人胃癌细胞系 (SGC790 1)中的生物学作用及其分子机理进行体内外研究。结果　 RA5 38及反义 c- myc重组体腺病毒 (Ad- RA5 38及 Ad- ASc- myc)对 SGC790 1细胞生长抑制率分别为 76 .3%和 44 .1%。 DNA梯度降解试验、原位末端标记、流式细胞仪显示 Ad- RA5 38及 Ad- ASc- myc诱导 SGC790 1细胞凋亡。它们均能抑制SGC790 1细胞 c- myc、bcl- 2、cyclin D1基因表达 ,并刺激 bax基因表达 ,对 p5 3、p16、TGase、ras基因的表达没有影响。经 Ad- RA5 38及 Ad- ASc- myc处理的 SGC790 1细胞致瘤性消失。Ad- RA5 38及 Ad- ASc- myc对裸鼠皮下移植瘤模型瘤内注射能有效降低肿瘤的生长速度 ,生长抑制率分别为 6 0 .7%和 6 8.9%。结论　 Ad-RA5 38、Ad- ASc- myc对胃癌细胞具有显著的生长抑制及凋亡诱导作用。其作用是 c- myc、bcl- 2、bax、cyclin D1等一系列基因表达变化及其相互作用的结果 ,与 p5 3、p16、TGa     

An ultra-metastatic model of human colon cancer in nude mice

An ultra-high metastatic model of human colon cancer was developed in order to represent highly malignant patient disease for which there is no current model. Surgical orthotopic implantation (SOI) of a histologically intact liver metastasis fragment derived from a surgical specimen of a patient with metastatic colon cancer was initially implanted in the colon, liver and subcutaneously in nude mice. This tumor did not metastasize for the first 10 passages. At the eleventh passage, the tumor exhibited metastasis from the colon to the liver, spleen, and lymph nodes. At this time, two selective passages were carried out by transplanting resulting liver metastases in the nude mice to the colon of additional nude mice. After these two passages, the tumor became stably ultra-metastatic and was termed AC3488UM. One-hundred percent of mice transplanted with AC3488UM with SOI to the colon exhibited local growth, regional invasion, and spontaneous metastasis to the liver, lymph nodes, and spleen. While the maximum size of the primary tumor was 0.9 g, the metastatic liver was over 9 times the weight of the normal liver with the maximum weight of the metastatic liver over 12 g. Liver metastases were detected by the tenth day after transplantation in all animals. Half the animals died of metastatic tumor 25 days after transplantation. Histological characteristics of AC3488UM tumor were poorly differentiated adenocarcinoma of colon. Mutant p53 is expressed heterogeneously in the primary tumor and more homogeneously in the liver metastasis suggesting a possible role of p53 in the liver metastasis. The human origin of AC3488UM was confirmed by positive fluorescence staining for in situ hybridization of human DNA. The AC3488 human colon-tumor model with its ultra-high metastatic capability in each transplanted animal, short latency and a short median survival period is different from any known human colon cancer model and will be an important tool for the study of and development of new therapy for highly metastatic human colon cancer.     

Staging, growth properties and metastatic behaviour of a transplantable murine T-cell lymphoma

Cell surface markers, enzymatic patterns, proliferation characteristics and metastatic behaviour of the DSA/2 derived SL2 lymphoma were determined. SL2 cells are sensitive to a heterologous antiserum to murine T-cells and to allo-antisera for Thy 1.2 and TL 1.2.3. They show acid-phosphatase, betaglucuronidase, acid-alpha-naphthytesterase and non-specific esterase staining. The reactions for ATP-ase, and 5'nucleotidase were negative. The SL2 tumour cells can be transplanted in vivo, growing rapidly both as an ascites or a solid tumour, and can be grown in vitro as a suspension culture (doubling time about 18 hours). One hundred cells kill an animal after i.p. transplantation, while 1,000 cells kill an animal after s.c. transplantation. Histopathological examination combined with TEM shows that SL2 metastasizes rapidly, especially after i.p. injection. The metastasizing cells reach the blood vessels in the lung septa and extravascular positions in the liver.     

Neurotropism of swine haemagglutinating encephalomyelitis virus (coronavirus) in mice depending upon host age and route of infection

Mice aged 1, 4 or 8 weeks were inoculated with haemagglutinating encephalomyelitis virus (HEV), strain 67N, by the intracerebral (i.c.), intranasal (i.n.), intraperitoneal (i.p.), subcutaneous (s.c.), intravenous (i.v.) or oral route, with different doses. In 1-week-old mice, mortality and mean time to death were mostly the same regardless of the inoculation route, except for the oral route, which appeared to be the least effective. The virus killed 4-week-old mice readily by all routes of inoculation except the oral, and 8-week-old mice by i.c., i.n. or s.c. inoculation. In descending order of efficacy, the routes of HEV infection were: i.c., i.n., s.c., i.p., i.v. and oral. To follow the spread of HEV from peripheral nerves to the central nervous system (CNS), the virus was inoculated subcutaneously into the right hind leg of 4-week-old mice. The virus was first detected in the spinal cord on day 2, and in the brain on day 3. The brain titres became higher than those of the spinal cord, reaching a maximum of 10(7)PFU/0.2 g when the animals were showing CNS signs. Viral antigen was first detected immunohistochemically in the lumbar spinal cord and the dorsal root ganglion ipsilateral to the inoculated leg; it was detected later in the pyramidal cells of the hippocampus and cerebral cortex, and in the Purkinje cells of the cerebellum but not in the ependymal cells, choroid plexus cells or other glial cells. The infected neurons showed no cytopathological changes.