Susceptibility of nude mice carrying the Fv-4 gene to Friend murine leukemia virus infection.

Fv-4 is a mouse gene that dominantly confers resistance to infection with Friend murine leukemia virus (F-MuLV) (S. Suzuki, Jpn. J. Exp. Med. 45:473-478, 1975). Despite complete resistance to ecotropic MuLV infection in mice carrying the Fv-4 gene, it is known that cells carrying the resistance gene in tissue culture do not always show resistance as extensive as that in vivo (H. Yoshikura and T. Odaka, JNCI 61:461-463, 1978). To investigate the immunological effect on resistance in vivo, we introduced the Fv-4 gene into BALB/c nude mice (Fv-4-/- nude[nu/nu]) by mating them with Fv-4 congenic BALB/c mice (Fv-4r/r nude+/+) and examined the susceptibility of the F2 progeny to F-MuLV. All BALB/c nude mice without the Fv-4 gene (Fv-4-/- nude[nu/nu]) were permissive to F-MuLV and developed erythroleukemia within 2 weeks after virus inoculation. The BALB/c nude mice with the Fv-4 gene (Fv-4r/r nude[nu/nu]) did not develop leukemia, and no or little virus was detected in the spleen 7 weeks after virus inoculation. The resistance to F-MuLV was dominant in (Fv-4 congenic BALB/c x BALB/c nude) F1 mice with the Fv-4r/- nude(nu/+) genotype as strictly as in (Fv-4 congenic BALB/c x BALB/c) F1 mice with the Fv-4r/- nude+/+ genotype. However, almost all BALB/c nude mice with the Fv-4r/- nude(nu/nu) genotype developed the disease within 7 weeks, and the virus was detected in all of their spleens even in the mice without leukemia. These results show that the resistance caused by the Fv-4 gene is recessive in nude mice and dominant in BALB/c mice. Some immunological effects, perhaps cell-mediated immunity, may play important roles in the resistance to F-MuLV infection in vivo in addition to the dosage effect of the Fv-4 product.     

Mouse strain variation and effects of oocyst dose in infection of mice with Eimeria falciformis, a coccidian parasite of the large intestine

Stockdale P. G. H., Stockdale M. J., Rickard M. D. and Mitchell G. F. 1985. Mouse strain variation and effects of oocyst dose in infection of mice with Eimeria falciformis, a coccidian parasite of the large intestine, International Journal for Parasitology15: 447–452. Five inbred strains of mice and three hypothymic (nude) strains were infected orally with different doses of E. falciförmis oocysts. After resolution of primary infection as determined by faecal oocyst output, mice were challenged orally with a second dose of E. falciformis. Amongst the intact mice, BALB/c proved the most resistant to primary infection, while C3H/He mice were most susceptible, in terms of faecal oocyst production. Resistance was far more dramatic in BALB/c mice given high numbers of challenge oocysts. In terms of mortality at high oocyst doses, CBA/H were the most susceptible. All of the strains of mice were highly resistant to reinfection. In the case of nude mice, BALB/c. nu/nu were more susceptible than CBA/H.nu/nu or C57BL/6.nu/nu both in terms of faecal oocyst production and mortality. Thus the most resistant inbred mouse strain (BALB/c) is the least resistant in the absence of T cells. Unlike intact mice, nude mice showed no resistance to reinfection, this result being in line with previous work on this and other Eimeria spp. in nude mice.     

Induction of B-Cell Lymphoma in BALB/c Nude Mice with an Ecotropic, B-Tropic Helper Virus Present in the Murine AIDS Virus Stock

The pathogenicities of the murine AIDS (MAIDS) virus complex (LP-BM5) and ecotropic helper virus (BM5eco) isolated from the complex to BALB/c nude mice were studied to elucidate the possible role of replication-competent helper virus in inducing the monoclonal outgrowth of lymphoid cells. Neither LP-BM5 nor BM5eco was pathogenic in adult BALB/c nude mice. However, B-cell lymphoma developed with a very high frequency when either virus was inoculated into newborn BALB/c nude (nu/nu) mice. The cells from the B-cell lymphoma were easily transplanted into nude mice. These results suggested that ecotropic helper virus in the MAIDS virus complex plays an important role in inducing the monoclonal outgrowth of lymphoid cells under immunodeficient conditions caused by defective virus.     

Cellular mechanisms in the protection against infection by Listeria monocytogenes in mice.

Listeria monocytogenes, in doses of 2-0 X 10(3) to 3-0 X 10(3) viable organisms, was injected into athymic nude mice, irradiated mice and mice treated with reticuloendothelial system-blocking agents. Viable counts on liver and spleen homogenates were made at intervals after infection. In both nude mice (nu/nu) and normal littermates (nu/+) of BALB/c background, the bacteria grew rapidly for 24 h but increased only slowly thereafter, to reach a plateau of about 10(5) per organ at 72 h. In nu/+ mice, the number of viable bacteria began to decrease after 6 to 9 days, with complete elimination by day 12. In nude mice, the number of Listeria remained at a stable level of approximately 10(5) per organ during the observation period of 21 days. In lethally irradiated nu/+ mice, bacteria grew progressively and extensively to reach 10(7) per spleen and 10(9) per liver by 72 h. Bacterial growth during the first 72 h was markedly enhanced by treatment with carbon particles, dextran sulphate 500 or silica. These enhancing effects were also observed in nude mice and in AKR, C3H/He and C57BL/6 animals. We conclude that both non-immune phagocytes and T cell-dependent mechanisms contribute to the resistance of mice to Listeria infection.     

Antibody response to simian virus 40 tumor antigen in nude mice reconstituted with T cells.

Athymic BALB/c nude mice (nu/nu) fail to generate circulating antibodies to simian virus 40 (SV40) tumor (T) antigen when immunized with SV40-transformed mouse cells or with T antigen positive somatic cell hybrids derived from SV40-transformed human and normal mouse parental cells. However, normal BALB/c mice readily produce antibodies to SV40 T antigen. When nude mice were reconstituted with normal syngeneic T lymphocytes from spleen or thymus source, the humoral immune responsiveness to SV40 T antigen was restored.     

Antibody-dependent cellular cytotoxicity and natural killer cytotoxicity of peritoneal cells from nude mice to herpes simplex virus-infected cells

Nude BALB/c mice (athymic) were more susceptible to fatal herpes simplex virus (HSV) than normal BALB/c mice (P = 0.002). The peritoneal cells of nude mice mediated levels of antibody-dependent cellular cytotoxicity (ADCC) of equal or greater magnitude than cells from normal BALB/c, heterozygote nu/+, or C57BL/6 mice. Unstimulated natural killer cytotoxicity of peritoneal cells from nude mice was higher (P less than 0.05) than that mediated by cells from C57BL/6 mice. Nude mice failed to make anti-HSV ADCC antibody 6 to 14 days post HSV inoculation, at times when nu/+, BALB/c, and C57BL/6 mice produced antibody. Passive reconstitution of nude mice with high titer intraperitoneal anti-HSV immune globulin provided circulating anti-HSV ADCC antibody and significant protection against lethal HSV infection.     

Natural T-cell regulation of spontaneous immunoglobulin secretion.

Splenic lymphocytes from nude (nu/nu), heterozygous/nude (+/nu), or wild type (+/+) mice were examined for their capacity to secrete immunoglobulin (Ig) in the absence of exogenous antigenic stimulation. Using the reverse hemolytic plaque assay, which measures spontaneous Ig secretion in vitro, whole spleen populations from both heterozygous/nude (+/nu) and nude (nu/nu) mice were found to have significantly fewer numbers of plaque-forming cells when compared with spleen cells from +/+ mice. Analysis of highly purified populations of T and B lymphocytes showed that increased numbers of B cells from +/+ mice were stimulated to secrete Ig when as few as 10% syngeneic +/+ T cells were added in vitro. In contrast, the same number of thymocytes suppressed the identical B-cell function. A comparison of splenic T cells obtained from either +/+ or +/nu mice revealed that T cells from +/nu animals stimulated additional plaque-forming activity by B cells from wild type or nude mice. The cellular mechanism underlying enhanced help by T cells from +/nu mice is unclear but may reflect a functionally restricted population of T cells inherited by heterozygous/ nude mice.     

Mouse strain difference in visceral larva migrans of Toxocara canis

The mode of larval migration (visceral larva migrans) in Toxocara canis infection was compared for BALB/c, C57BL/6, C3H/He, DBA/2, NC and BALB/c nude mice following oral infection with 400 eggs. The mean recovery of larvae from the liver on day 2 post infection (PI) was not different in terms of the strain, age or sex of the mice. The number of larvae recovered from the liver decreased in all strains on days 6, 12 and 21 PI, but the mean for BALB/c and (NC X BALB/c) F1 mice was significantly higher than that for C567BL/6, NC and BALB/c nude mice, unless the total number of larvae in the carcasses on day 21 PI was the same among those strains including athymic nude mice. The mean recovery of larvae from the liver on day 6 PI increased with age in both NC and BALB/c mice, although no sex difference was observed. From these results, it is emphasized that the age and strain of animals should be properly selected for animal experimentation with T. canis infection.     

Characteristics of mouse lymphoid cells proliferating in vitro by recombinant human interleukin 2 (TGP-3): comparison between normal and nude mice

Various lymphoid cells obtained from BALB/c and BALB/c nu/nu mice were cultured in vitro with recombinant human interleukin 2 (rIL 2), and the characteristics of responder cells to rIL 2 were analyzed. Spleen cells, lymph node cells, and thymocytes except for bone marrow cells obtained from BALB/c mice remarkably proliferated in response to rIL 2. On the other hand, among lymphoid cells obtained from BALB/c nu/nu mice, only lymph node cells showed significant proliferation by rIL 2. Flow cytometric analysis revealed that mainly two types of lymphoid cells were proliferating in response to rIL 2 in BALB/c mice, i.e., Thy 1+, Lyt 1-, Lyt 2- and Thy 1+, Lyt 1-, Lyt 2+ cells. On the other hand, most of the proliferating cells were Thy 1+, Lyt 1-, Lyt 2- cells in BALB/c nu/nu mice. Treatment with various antibodies plus complement revealed that the majority of IL 2-responsive cells in BALB/c mice were Thy 1+, Lyt 1+, and Lyt 2+, although a minor part of them were Thy 1-, Lyt 1-, and Lyt 2-. On the other hand, a predominant type of the IL 2-responsive cells in BALB/c nu/nu mice were Thy 1-, Lyt 1-, and Lyt 2-, though some were Thy 1+. Nonspecific killer activity against tumor cells increased to variable extents in all of the lymphoid cells of both strains after culture with rIL 2. Our results indicate that mouse responder cells to rIL 2 have the following characteristics. First, the responder cells exist abundantly among spleen, lymph nodes, and thymus in normal mice, though their cell lineages are heterogeneous; one is of T cell lineage and the other of natural killer (NK) cell lineage. Second, nude mice are defective in the responder cells of T cell lineage but not of NK cell lineage. Moreover, the responder cells in nude mice predominantly accumulate in the lymph nodes but not other lymphoid organs.     

Hymenolepis nana: adoptive transfer of protective immunity and delayed type hypersensitivity response with mesenteric lymph node cells in mice

A marked degree of footpad swelling was observed in BALB/c mice infected with Hymenolepis nana eggs, when soluble egg antigen was injected into their footpads 4 to 21 days after the egg infection, indicating delayed type hypersensitivity responses in infected mice. Adoptive transfer with mesenteric lymph node cells from donor mice (BALB/c strain; +/+) infected with eggs 4 days before cell collection could confer this hypersensitivity to recipient nude mice (BALB/c strain; nu/nu). These mesenteric lymph node cells were then divided into two fractions, blast-enriched and blast-depleted cells, by density gradient centrifugation with Percoll. The recipients intravenously injected with the blast-depleted cell fraction showed a marked increase in footpad thickness, whereas the intravenous transfer of the blast-enriched cell fraction resulted in an insignificant increase in footpad thickness. The transfer of the blast-enriched cell fraction, but not of the blast-depleted cell fraction, conferred a strong adoptive immunity on syngeneic recipient nude mice, when the immunity transferred was assessed by examining cysticercoids developed in the intestinal villi on Day 4 of challenge infection. The lack of delayed type hypersensitivity response in mice that received the blast-enriched cell population was not due to a lack of the capacity of the cells to induce the response, because the cells were capable of inducing a significant increase in thickness of footpads of normal mice when these cells were locally injected into the footpad together with soluble egg antigen.(ABSTRACT TRUNCATED AT 250 WORDS)     

Spontaneous tumors in nude mice: effect of the viable yellow gene.

The incidence and type of spontaneous tumors in athymic nude (nu/nu) mice (partially inbred in CBA/H background) which were also carrying the viable yellow gene (Avy, derived from C57BL/6JAvy mice), were comparable to those observed in the phenotypically normal nu/+ and +/+ control crosses carrying the Avy gene. The Avy gene increases the incidence of spontaneous and induced tumors in most mouse strains. These results would argue against the thymus dependency of the putative immunological surveillance mechanisms.     

An epizootic Staphylococcus infection in a nude mouse colony

An epizootic of Staphylococcus infection causing abscesses was encountered in a small-scale breeding colony of nude mice of BALB/c background. The incidence of abscess was sporadic and mostly nude (nu/nu) mice aged over 3 months were affected. Staphylococcus aureus was isolated from the face, oral cavity, and feces of almost all nu/nu and heterozygous (nu/+) mice in the colony. After a prolonged time period, up to 10 to 14 months of age, almost all the S. aureus-carrying nu/nu mice produced abscesses and eventually died. Athymicity of the host seemed to be a prerequisite for the abscess formation since nu/+ mice were spared from the lesions. Also, transfer of immunocompetent spleen cells cured the abscesses of the affected nude mice.     

Studies on immune responses to larval cestodes in mice. Increased susceptibility of certain mouse strains and hypothymic mice to Taenia taeniaeformis and analysis of passive transfer of resistance with serum.

Various inbred strains of mice vary markedly in their susceptibility to the larvae of the cestode, Taenia taeniaeformis. Males are generally more susceptible than females and the most susceptible common inbred mouse strains are those which are deficient in C5 and/or C4 components of complement. However, no genetic evidence is yet available to implicate loci controlling complement levels in susceptibility/resistance, and multiple genetic factors appear to be operative. Hypothymic, nu/nu ("nude") mice of the relatively resistant mouse strain, BALB/c, are highly susceptible in that cystic larvae in the liver develop in large numbers and more rapidly than in intact BALB/c.nu/+litter-mates. Cyclophosphamide pretreatment also increases the susceptibility of relatively resistant strains of mice in terms of both the number and size of liver cysts. Hypothymic and intact mice can be protected, absolutely, by an injection of serum from infected intact mice, provided the serum is given to recipient mice close to the time of oral egg administration. The protective activity of immune serum is absorbed totally by staphylococcal protein A-Sepharose columns and can be abolished by treatment of recipients with cobra venom factor. Cyst fluid from established larvae facilitates the activity of subhaemolytic amounts of guinea pig complement in a standard direct PFC assay. The data suggest that complement-fixing antibodies are responsible for inhibition of establishing larvae in mice and that one method of protection for established cystic larvae involves the alteration of host complement activity within the cyst.     

Studies of congenitally immunologic mutant New Zealand mice. II. Absence of T cell progenitor populations and B cell defects of congenitally athymic (nude) New Zealand Black (NZB) mice.

Congenitally athymic (nude) mice on an NZB, NZW, and BALB/c background were produced by repetitive selective backcrossing. F'12 generation nude mice of these three strains were compared to their littermate nu/+ controls with respect to survival, histology, blood counts, splenic surface markers, response to mitogens, spontaneous plaque-forming cells, and appearance of naturally occurring thymocytotoxic antibodies (NTA). Under specific pathogen-free conditions, NZB nude mice survive less than 3 weeks, dying of a runting-like disease with infection by local normally noninvasive organisms. A contributing factor to his premature death is the relative absence of T cell progenitor populations in the NZB nude vs NZW nude or BALB/c nude groups. Furthermore, NZB nude mice have a significantly earlier appearance of NTA than nu/+ littermates and likewise appear to have heightened spontaneous polyclonal B cell responses against the haptens dansyl, nitroiodophenyl, trinitrophenyl,2,4 dinitrophenyl, and sulfonate. It is suggested that NZB mice have several critical immunologic defects, including abnormalities of thymic epithelial cells, T cell differentiation pathways, and chronically polyclonal activated B cell populations. These defects interact to produce the clinical expression of autoimmunity.     

Histopathological studies on experimental Cryptococcosis in nude mice

Cryptococcosis in nude (nu/nu) mice was examined histopathologically. In addition, effects of carrageenan and lymph node cell transfer againstCryptococcus infection were investigated. As controls, heterozygous littermates (nu/+mice) and mice of strain ddy (ddy mice) were employed.Each mouse was inoculated intravenously with 10⁵ yeast cells ofCryptococcus neoformans suspended in 0.2 ml phosphate-buffered saline. Two mice out of each group were sacrificed at appropriate intervals up to 25 days after inoculation and histopathological sections were prepared from them. They were stained with H & E and by PAS method. Histopathological characterristic in the brain was cyst formation with no cellular response. The brain was more severely in the nu/nu mice than in either the nu/+ or ddy mice. In the liver, there was a major difference in histopathological findings between the nu/nu and either of the other groups of mouse. In the nu/nu mice, cyst formation with no cellular response was induced, and on the contrary granuloma formation in the nu/+ and ddy mice. However, the granuloma formation was inhibited in the livers of the nu/+ and ddy mice by administration of carrageenan, and induced in the nu/nu mice by cell transfer. In the spleen and lymph nodes, lesions were severer in nu/nu mice than in either the nu/+ or ddy mice.These results suggested that the fungus' invasiveness of mice was strongly influenced by T-cell dependent mechanism.     

Genetic control of the immune response to collagen. III. Coordinate restriction of cellular cooperation and antigen responsiveness by thymus-directed maturation

The H-2 restriction of T helper cells from thymus-reconstituted nude mice was examined. Hybrid athymic mice were bred from BALB/c.nu and C57BL/6.nu parental strains and reconstituted with fetal thymus tissue from either parental strain. T helper cells from these mice, immunized to SRBC, were restricted to cooperation with B cells of the thymic H-2 haplotype. These T helper cells were shown to have originated from the F1 host by functional sensitivity to antisera and complement. The H-2 restriction of thymus-reconstituted F1 nude mice was further investigated by examining expression of the Ir-collagen phenotype. Results showed that the level of antibody produced in response to type I calf collagen in thymus chimeras correlates with the H-2 haplotype (high responder or low responder) of the reconstituting thymus. These experiments indicate that the thymus environment of T cell maturation influences both the H-2 restriction and Ir-phenotype of a responding immune system.     

Foreign serum-induced bile duct lesion (BDL) in athymic BALB/c nude mice

To investigate a role of cellular immunity in foreign serum-induced bile duct lesion (BDL) in mice, athymic BALB/c nude (nu/nu) mice were intraperitoneally injected with swine serum (SS) twice a week up to 8 weeks and were compared with euthymic BALB/c heterozygote (nu/+) and wild-type (+/+) mice treated with SS in the same way for 4 weeks. All immunized nu/+ and +/+ mice developed marked BDL, and their sera showed high anti-SS IgE and IgG1 antibody titers, whereas no immunized nu/nu mice developed lesions, and their sera showed no elevation of antibody titers. Next, nu/nu mice were reconstituted with splenocytes derived from nu/+ mice, and then were intraperitoneally injected with SS twice a week for 3 weeks. Most of the reconstituted nu/nu mice developed BDL, and their sera showed the elevation of anti-SS IgE and IgG antibody titers. These results suggest that cellular immunity may play a pivotal role in the pathogenesis of swine serum-induced BDL.     

Role of L3T4+ and LyT-2+ cells in experimental visceral leishmaniasis

In contrast to euthymic (nu/+) BALB/c mice, athymic nude (nu/nu) BALB/c mice fail to control the visceral intracellular replication of Leishmania donovani, do not generate the macrophage-activating lymphokine IFN-gamma, and show little or no granulomatous tissue response. To characterize the T cell requirement for successful defense against L. donovani, nude mice were first reconstituted with unfractionated nu/+ immune spleen cells, which readily conferred the capacity to control and eliminate visceral (hepatic) L. donovani. In reconstituted mice, acquired resistance was paralleled by the ability of spleen cells to generate high levels of leishmanial Ag-stimulated IFN-gamma and the development of well formed liver granulomas. In contrast, nude mice reconstituted with either L3T4+- or Lyt-2+-enriched immune spleen cells alone failed to control visceral parasite replication and did not develop effective granulomas despite the finding that transfer of L3T4+ cells largely and Lyt-2+ cells partially restored the capacity to secrete IFN-gamma. To determine whether both T cell subsets were also required in a normal host, nu/+ BALB/c mice were treated with cell-depleting anti-L3T4 and anti-Lyt-2 mAb. Depletion of either T cell subset inhibited the acquisition of resistance to L. donovani and impaired the tissue granulomatous response. Thus, successful T cell-dependent host defense towards intracellular L. donovani and the tissue expression (granulomas) of this mechanism appear to require both L3T4+ and Lyt-2+ cells. A primary role for the L3T4+ cell may be IFN-gamma production; the role of the Lyt-2+ cell and the precise interaction of the two T cell subsets remain to be identified.     

Requirement for NK cells in CD40 ligand-mediated rejection of Philadelphia chromosome-positive acute lymphoblastic leukemia cells.

We have previously developed a murine model of Philadelphia chromosome-positive acute lymphoblastic leukemia by i.v. injection of a pre-B ALL cell line (BM185) derived from Bcr-Abl-transformed BALB/c bone marrow. We are studying the potential to elicit autologous antileukemic immune responses by introducing genes encoding immunomodulators (CD40 ligand (CD40L), CD80, and GM-CSF) into leukemia cells. BM185 cells expressing CD40L or CD80 alone, when injected into BALB/c mice, were rejected in approximately 25% of mice, whereas cohorts receiving BM185 cells expressing two or more immunomodulator genes rejected challenge 50-76% of the time. The greatest protection was conferred in mice receiving BM185 cells expressing all three immunomodulators. Addition of murine rIL-12 treatments in conjunction with BM185/CD80/CD40L/GM-CSF vaccination allowed rejection of preestablished leukemia. BM185 cell lines expressing CD40L were rejected in BALB/c nu/nu (nude) mice, in contrast to cell lines expressing CD80 and/or GM-CSF. Nude mice depleted of NK cells were no longer protected when challenged with BM185/CD40L, demonstrating a requirement for NK cells. Similarly, NK cell depletion in immunocompetent BALB/c mice resulted in a loss of protection when challenged with BM185/CD40L, confirming the data seen in nude mice. The ability of CD40L to act in a T cell-independent manner may be important for clinical applications in patients with depressed cellular immunity following chemotherapy.     

Cells with natural killer activity in the cerebrospinal fluid of normal mice and athymic nude mice with acute Sindbis virus encephalitis

Sindbis virus causes an acute, nonfatal inflammatory encephalitis in weanling BALB/c mice. Mononuclear inflammatory cells are present in the cerebrospinal fluid (CSF) as well as in the parenchyma of the brain. Both aspects of this inflammatory response were eliminated by treatment with cyclophosphamide. Athymic nude (nu/nu) mice developed no inflammation in the brain, but did develop a CSF pleocytosis that peaked on day 2 after infection. The time course of the appearance of cells in the CSF was earlier in nu/nu mice than their heterozygote (nu/+) littermates. The pleocytosis in nu/nu mice reached a peak on day 2, whereas in nu/+ mice the peak was on day 4, as it is in normal BALB/c mice. To determine whether some of the CSF cells in nu/nu mice may be natural killer (NK) cells, NK activity was measured in a 4-hr assay by using a YAC-1 target cell. NK cell activity in the spleen and peripheral blood was induced by infection with Sindbis virus in nu/nu mice with a similar time course to that of nu/+ mice (peak 1 day after infection). CSF from nu/nu mice had NK activity present 2 days after infection that was greater than that present in either the peripheral blood or spleen. BALB/c and nu/+ mice had insufficient cells present for assay at day 2, but BALB/c mice had NK activity present in the CSF 3 and 5 days after infection that exceeded that in the peripheral blood or spleen. Brain interferon was detectable on day 1 in nu/nu mice, but not until day 2 in nu/+ mice even though the amounts of brain virus were the same in the two groups at all time points. It is concluded that cells with NK activity contribute to the CSF pleocytosis induced by acute Sindbis virus encephalitis.