Efficient generation of transgenic BALB/c mice using BALB/c embryonic stem cells

BALB/c is one of the most widely used and best characterized mouse strains in immunology. For various applications, it is necessary to generate BALB/c transgenic mice. However, using the conventional microinjection technique it is extremely inefficient to produce transgenic BALB/c mice since the one-cell stage BALB/c embryos are highly vulnerable to pronuclear DNA microinjection. To overcome this problem, we have investigated the generation of Egr-1 (early growth response gene) transgenic mice via the transfection of BALB/c embryonic stem cells. Transfectants carrying Egr-1 constructs comprising either the immunoglobulin heavy chain or the MHC class II promoter/enhancer system were injected into C57BL/6 host blastocysts resulting in chimeric mice. For both type of expression vectors, transgenic offspring of the germline chimeras expressed recombinant Egr-1 in lymphoid tissues containing B cells. This demonstrates the successful generation of Egr-1 transgenic BALB/c mice using transfected ES cell.     

Neonatal stimulation, maternal behavior, and accelerated maturation in BALB/c mice

An experiment was conducted to examine the effects of neonatal handling and hypothermia on infant physical maturation and growth and on maternal behavior in BALB/c mice. Stringent methodological and statistical controls were employed for experimenter bias and litter effects. No evidence appeared to support claims that neonatal stimulation leads to accelerated physical maturation. Alterations in maternal behavior patterns were found only immediately following hypothermia of pups. Maternal behavior did not correlate highly with offspring maturational rates, but maternal weight and age and pup birth weight were highly predictive of infant physical maturation.     

Inoculation of BALB/c mice with fish-pathogenic nodaviruses

To investigate the pathogenicity of fish-pathogenic nodaviruses (betanodaviruses) in mammals, weanling mice were inoculated with striped jack nervous necrosis virus (SJNNV; the type species of the genus Betanodavirus) or redspotted grouper nervous necrosis virus (RGNNV), which belong to different genotypes. After inoculation with 10(7.5) TCID50, either intramuscularly or intraperitoneally, mice remained clinically normal for the 14-day observation period. In a subsequent short-term (72 h) experiment, mice inoculated intramuscularly with 10(7.5) TCID50 yielded virus (10(6) to 10(5) TCID50/g) from muscle at the site of injection at 3, 24 and 72 h post-infection; they also yielded virus from the kidneys (10(5) TCID50/g) at 3 and 24 h post-infection, but by 72 h virus had become almost undetectable at this site. Throughout the experiment, no virus was detected in the sites that are target organs of betanodaviruses in fish, namely, the brain, spinal cord and eye. The results indicate that the mouse is not susceptible to betanodaviruses.     

Enhanced sensitivity of DEAE-dextran treated spleen cells from normal BALB/c mice,B-lymphocyte depleted BALB/c mice and nude mice toin vitro antibody-complement mediated immune cytolysis

The sensitivity of thein vitro antibody-complement mediated dye exclusion cytotoxicity teat when carried out with rabbit antisera and mouse target cells was investigated with the polycation DEAE-dextran present in the cell suspension. One antiserum was raised against BALB/c mouse thymus cells (ATS) another against nude (nu/nu) mouse spleen cells (ANS). Target cells were from the spleens of normal BALB/c mice, cyclophosphatamide treated (B-cell depleted) BALB/c mice, and nude (T-cell depleted) mice. DEAE-dextran enhanced the sensitivity in all antiserum-target cell combinations, the enhancing effect being most pronounced when ANS was used against nude spleen cells.     

Individual variations of the immune response in BALB/c mice

The nature and the causes of variations of the immune response to thyroid hormones are analyzed in BALB/c mice. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 80–82, January, 1995 (Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences)     

Carcinogenicity of 1,2-dimethylhydrazine dihydrochloride in BALB/c mice

Summary The carcinogenicity of 1,2-dimethylhydrazine dihydrochloride (DMH) by oral, intragastric and subcutaneous administration was examined in 339 BALB/c mice. Subcutaneous injection of DMH induced intestinal tumors in the lower colon of all mice. After oral administration it induced a high incidence of vascular tumors in the liver and soft tissues, but colon tumors were found in only 2 mice when given at a high dosage. On intragastric administration, it induced a fairly high incidence both of colon and vascular tumors. The sites and incidences of vascular tumors and squamous cell carcinomas of the perianal glands were also described.This work was supported in part by a Grant-in Aid for Cancer Research from the Ministry of Education, Japan.     

Experimental production of actinomycetoma in BALB/c mice.

Chronic actinomycetoma associated with grain production was induced in BALB/c mice by subcutaneous inoculation of live Nocardia brasiliensis in Freund incomplete adjuvant into the hind footpads. Similar inoculation of N. asteroides and N. caviae resulted in local tumor formation which healed spontaneously after 5 months, the disease disseminating into the peritoneum, where masses or organisms could be detected. Grains were recovered from superficial skin lesions of N. caviae, but not from the N. asteroides-infected mice. Mycetoma lesions, appearing as early as 1 month after inoculation of 1.2 X 10(7) colony-forming units of N. brasiliensis per ml or as late as 3 months with inoculation of 1.0 X 10(5) colony-forming units per ml, became persistent and were readily detectable even 6 months after inoculation. No spontaneous healing occurred, and grains were recovered at different stages of the disease. Saline suspensions of N. brasiliensis also produced typical mycetoma lesions, although the incubation period was ca. 6 months. Adjuvant addition appeared to accelerate the onset of the disease. Experimental production of actinomycetoma in laboratory animals allows the study of many unanswered aspects of the disease and also provides a suitable model for therapeutic trials in the search for new and more effective chemotherapeutic agents.     

Characterization of Bartonella henselae-specific immunity in BALB/c mice

BALB/c mice were inoculated with Bartonella henselae by both systemic and mucosal routes. Culture analysis of tissues from mice infected intraperitoneally with a high dose of B. henselae yielded positive results 24 hr after infection. However, culture analysis of blood taken between 6 hr and 7 days after infection from groups receiving live B. henselae were negative. Following intraperitoneal infection, B. henselae was detected by polymerase chain reaction in liver and mesenteric lymph nodes by 6 hr and up to 7 days after infection in liver, kidney and spleen tissue. Enzyme-linked immunosorbent assay (ELISA) of serum samples collected as early as 13 days after infection indicated humoral immune responses to B. henselae. Specific humoral responses remained through week 6. Analysis of faecal samples revealed induction of B. henselae-specific immunoglobulin A by day 28 after infection. In addition, B. henselae-specific cellular responses were indicated by a positive delayed-type hypersensitivity and a T helper 1 (Th1) (CD4+ T cell)-type cytokine response following in vitro stimulation of splenocytes. The significance and implications of these data in relation to B. henselae infections are discussed.     

BALB/c小鼠巨细胞病毒性心肌炎模型的特征

目的：探讨BALB/c小鼠巨细胞病毒(MCMV)性心肌炎模型的特征。方法:60只4周龄BALB/c小鼠随机分成2组：实验组(36只，MCMV腹腔注射)和对照组(24只，3T3细胞裂解液腹腔注射)。在注射后3、7、14、21、28、35、42、49、56、63和70 d，记录心电图，测血清抗心肌β1受体抗体，分批处死小鼠行心肌病理、免疫组化和MCMV DNA检测。结果:实验组心肌炎累积发病25只(25/36，69.4%)，死亡4只(4/36，11.1%)；心肌炎急性期心肌呈现弥漫性炎性细胞浸润和灶性心肌细胞变性坏死，慢性期心肌间质散在炎性细胞浸润，急慢性期心肌炎病理积分均在2分或以下；免疫组化示急性期心肌IL-1β和TNF-α蛋白强阳性表达。实验组心律失常累计发生率达50.0%，可出现各种心律失常，急性期以窦性、房性心律失常和传导阻滞为主，慢性期以室性和房性心律失常为主。实验组3-7 d时心肌组织可检测到MCMV DNA片段，14-70 d时则不能检测到。实验组前5周血清抗β1受体抗体滴度为0，第6-10周明显升高；对照组前7周该抗体滴度为0，第8-10周轻微升高。结论:MCMV心肌炎并不严重，心肌细胞变性坏死具有局灶性和散在性特点，可出现各种心律失常；心肌炎早期病变和心律失常的发生可能与病毒感染直接损伤有关，慢性期病变和心律失常的发生则可能与抗β1受体抗体的作用有关。     

Immunogenicity of SARS inactivated vaccine in BALB/c mice

Severe acute respiratory syndrome (SARS) is a serious infectious threat to public health. To create a novel trial vaccine and evaluate its potency, we attempted to generate a SARS inactivated vaccine using SARS coronavirus (SARS-CoV) strain F69 treated with formaldehyde and mixed with Al(OH)3. Three doses of the vaccine were used to challenge three groups of BALB/c mice. We found that the mice exhibited specific IgM on day 4 and IgG on day 8. The peak titers of IgG were at day 47 in low-dose group (1:19,200) and high-dose group (1:38,400) whereas in middle-dose group (1:19,200), the peak was at day 40. On day 63, the IgG levels reached a plateau. Neutralization assay demonstrated that the antisera could protect Vero-E6 cells from SARS-CoV's infection. Analysis of the antibody specificity revealed that the mouse antisera contained a mixture of antibodies specifically against the structure proteins of SARS-CoV. Furthermore, the mouse antisera conferred higher amount of antibodies against protein N, polypeptide S4 and S2 than those of proteins M and 3CL. These findings suggest that the inactivated SARS-CoV could preserve its antigenicity and the inactivated vaccine can stimulate mice to produce high levels of antibodies with neutralization activity. Results also suggest that polypeptides originating from protein N or S might be a potential target for the generation of a recombinant SARS vaccine.     

The elimination of mycoplasma from infected hybridomas by passaging in BALB/c mice

Hybridomas, which were found to be infected with mycoplasma, were cleared of contamination by passaging in BALB/c mice. This procedure was successfully applied to four of five cultures examined. The procedure offers a simple and effective means of eliminating mycoplasma from valuable and sometimes irreplaceable hybridoma cell cultures.     

BALB/c鼠和裸鼠呼吸道合胞病毒感染比较研究

目的 比较普通BALB/c鼠和裸鼠呼吸道合胞病毒(RSV)感染免疫及炎症反应特点.方法 BALB/c鼠和裸鼠感染RSV后不同时间空斑形成试验检测肺组织病毒滴度,计数支气管肺泡灌洗液(BALF)白细胞总数和分类,HE染色分析肺组织病理学改变,免疫组化检测肺组织F4/80+细胞和CD49b+细胞.ELISA检测BALF中TNF-α、IFN-r、IL-12和IL-10浓度.结果 BALB/c鼠和裸鼠感染RSV后肺组织病毒滴度在第3天达峰值,感染裸鼠带毒时间更长,在感染后各天病毒滴度明显高于BALB/c鼠(P＜0.05),肺组织病理改变也更重.感染BALB/c鼠和裸鼠BALF白细胞总数明显升高,分类以淋巴细胞为主.感染裸鼠与感染BALB/c鼠比较,肺组织检测到更多的F4/80+巨噬细胞和CD49b+NK细胞(P＜0.05),BALF中TNF-α、IL-12和IL-10水平更高(P＜0.05).结论 RSV感染裸鼠与BALB/c鼠比较,病毒复制水平更高,时间更持久,炎症反应更重.单核巨噬细胞和NK细胞是RSV感染重要的免疫细胞和炎症细胞,炎症反应强度并不一定与T细胞免疫应答平行.     

BALB/c小鼠肥大细胞瘤/白血病模型的建立

目的研究建立BALB/c小鼠肥大细胞瘤/白血病模型。方法 BALB/c小鼠尾静脉注入小鼠肥大细胞瘤P815细胞,实验按每只小鼠接种细胞数量分为1×10^7/只组、5×10^6/只组、2.5×10^6/只组、1×10^6/只组、5×10^5/只组、1×105/只组和溶剂（RPMI1640培养液）对照组。观察小鼠的生存状态、体重及肝肺脾（重量、形态、病理）、染色体、血涂片、骨髓涂片、白细胞及血小板计数。结果注入P815细胞≥1×106/只的所有组小鼠均死亡,〈1×10^6/只的所有组生存良好,且死亡小鼠的生存时间与注入细胞数量呈负向依赖关系（P〈0.05）。死亡组小鼠体重较注射前相当或减轻、肝肺脾重较对照组及未死亡组显著增加（P〈0.05）;肝质地变硬,表面可见大量大小不一的白色结节突起,部分脾肺可见出血梗死灶,病理示肝脾有大量异形肥大细胞瘤细胞浸润;脾细胞染色体分析可见肥大细胞瘤细胞的非正常染色体核型;白细胞和血小板计数较对照组降低（P〈0.01）,血涂片可见少量肥大细胞瘤细胞,骨髓涂片示骨髓原始细胞比例增高。结论 P815细胞通过静脉注射能使BALB/c小鼠形成肥大细胞瘤/白血病,可作为肿瘤实验研究的一种模型构建方法。     

Comparison of ascites production for monoclonal antibodies in BALB/c and BALB/c-derived cross-bred mice

BALB/c male mice were mated with either Swiss-Webster or MF1 females to produce first generation cross-bred offspring. Hybridoma cell lines, from the fusion of P3-NS1-Ag4/1 myeloma cells with spleen cells sensitised to the porcine coronavirus causing transmissible gastroenteritis, were injected intraperitoneally into these mice to produce ascitic fluid containing monoclonal antibodies. Mice of 11 weeks of age weighing between 26 and 34 g were used. The volume of ascites produced by mice injected with four of the five hybrid cell lines tested was greater in the cross-bred offspring than in the BALB/c parent. The fifth cell line gave comparable volumes in the MF1 cross-breed and BALB/c parent but a lesser volume in the Swiss-Webster cross-breed. The antibody titres of the ascites as determined by virus neutralisation, radioimmune and indirect immune fluorescence assays, did not differ significantly between mouse types. The ability to use all offspring from a litter of cross-bred mice, irrespective of sex, and the increased volume of ascitic fluid formed in each mouse, permits fewer animals to be used for the production of ascites in these strains, thereby offering considerable economic and ethical advantages over the use of BALB/c mice.     

Immunomodulation of inherent behavior in C57Bl/6 and BALB/c mice with antibodies to glutamate

Immunization of BALB/c mice with glutamate-BSA conjugate reduced anxiety and improved passive avoidance retention, while in C57Bl/6 mice immunization disturbed passive avoidance retention, but had no effect on anxiety. Interstrain differences in the shuttle box behavior were found between control animals.     

Absence of cholinergic airway tone in normal BALB/c mice

Basal airway smooth muscle (ASM) tone has not been demonstrated in mice in vivo. To determine whether basal ASM tone is present in mouse airways we measured respiratory system impedance (Zrs) before and after either atropine or bilateral vagotomy. Zrs was measured using forced oscillations delivered via a wave-tube during slow ( approximately 35s) inflation-deflation maneuvers between transrespiratory pressures (Prs) of 0 and 20 cm H2O. A constant-phase tissue model was applied to the Zrs to calculate airway resistance (R aw), tissue damping (G) and elastance (H). Thoracic gas volume (TGV) was determined plethysmographically at Prs=0 cm H2O and by integration of the inspiratory flow. The relationship between conductance (G aw=1/R aw) and TGV during inflation was also examined. Neither atropine nor vagotomy produced any change in R aw, H, eta (=G/H), TGV or the slope of G aw vs. TGV that was different to that observed in the relevant control groups. These data show that BALB/c mice do not have cholinergic ASM tone in vivo.     

普鲁卡因酰胺等诱导BALB／c小鼠产生抗核抗体

为了建立药物诱导狼疮（DIL）的动物模型,用普鲁卡因酰胺（Pca)、盐酸肼苯哒嗪（Hyd)和2,2-偶氮-双（3-乙苯基-噻唑啉-6-硫酸）（ABTS）对不同品系小鼠腹腔给药,用ELISA和间接免疫荧光法检测抗核抗体。三种药物都能够诱导小鼠产生抗核抗体,Pca诱导小鼠产生核抗体的阳性率为25%,而Hyd、ABTS诱导的阳性率均为12.5%。Pca、Hyd和ABTS都能诱导BALB/c小鼠而不是C57BL/6小鼠产生抗核抗体,其中DNA特异的抗体主要是IgG,而对组蛋白特异的抗体主要是IgM。结果表明在人体导致DIL的药物Pca、Hyd和ABTS能诱导昆明鼠及BALB/c小鼠产生抗核抗体,提示DIL的发生受遗传背景的影响。