Variable biotherapeutic effects of Lactobacillus acidophilus isolates on orogastric and systemic candidiasis in immunodeficient mice

Two commercially available isolates of Lactobacillus acidophilus (NCFM and LA-1) were compared for their capacities to protect immunodeficient bg/bg-nu/un and bg/bg-nu/+ mice from candidiasis. L. acidophilus NCFM prolonged survival of adult and neonatal bg/bg-nu/nu mice, inhibited disseminated candidiasis in both mouse strains, suppressed weight loss associated with Candida albicans infection in bg/bg-nu/nu females, but did not decrease the severity or the incidente of orogastric candidiasis in gnotobiotic mice. L. acidophilus LA-1 suppressed numbers of C. albicans in the alimentary tracts of bg/bg-nu/+ mice and reduced the severity of mucosal candidiasis in bg/bg-nu/nuand bg/bg-nu/+ mice; however, L. acidophilus LA-1 did not improve the survival of bg/bg-nu/nu mice after oral challenge (colonization) with C. albicansand it was associated with lethality in gnotobiotic adult female bg/bg-nu/nu mice. These results demonstrate that the two isolates of L. acidophilus differed in their capacity to protect immunodeficient mice from candidiasis.     

Natural cellular resistance of beige mice against Cryptococcus neoformans

Previous reports have demonstrated that natural killer (NK) cells are capable of inhibiting the growth of Cryptococcus neoformans in vitro, and recent studies indicate that adoptively transferred NK cell-enriched spleen cell populations enhance clearance of cryptococci from the tissues of cyclophosphamide-pretreated recipients. The primary objective of these studies was to confirm that NK cells participate in early clearance of C. neoformans in vivo. Secondarily, the anti-cryptococcal activities of polymorphonuclear leukocytes and macrophages were examined. Seven-week-old C57BL/6 bg/+ mice, which have normal levels of NK cell activity, were compared with their bg/bg littermates, which have impaired NK cell function. One and 3 days after injecting both groups of mice i.v. with 2 X 10(4) cryptococci, we assessed the NK cell activities in spleens, lungs, and livers and clearance of the organism from corresponding tissues as determined by the mean log10 numbers of cryptococcal colony-forming units (CFU) per organ. Three days postinfection, the mean numbers of cryptococcal CFU in lungs and spleens of bg/+ mice were significantly lower than in the corresponding organs of bg/bg mice. NK cell activities in spleens and lungs of bg/+ mice were significantly higher than were the NK cell activities in similar cell populations from bg/bg mice. In contrast, the mean numbers of cryptococcal CFU in livers of the two groups of animals were nearly equivalent, a situation not unexpected, since liver NK cell activities were extremely low and similar in both groups of animals. Although these data indicated a correlation between early clearance of cryptococci from tissues and levels of NK cell activities in the corresponding tissues, it was also possible that differences in phagocytic cell function between the bg/+ and bg/bg animals could account for the observed differences in clearance of cryptococci from the tissues. Therefore, phagocytic cells from the two groups of animals were compared with respect to their abilities to phagocytize and inhibit the growth of cryptococci and to their abilities to respond to chemotactic stimuli in vivo. Peritoneal PMNL from bg/+ and bg/bg mice were similar in their abilities to phagocytize and inhibit the growth of cryptococci, as well as in their chemotactic responses to viable cryptococci or sodium caseinate. In addition, there were no differences in splenic macrophage functions between the two groups of mice.(ABSTRACT TRUNCATED AT 400 WORDS)     

Cryptococcosis in beige mice: the effect of congenital defects in innate immunity on susceptibility

The influence of the beige (bg/bg) mutation on susceptibility to cryptococcosis was assessed by mortality, quantitative culturing, and histopathology of infected organs from bg/bg and bg/+ mice. Immunodeficient bg/bg mice were more susceptible to systemic cryptococcosis than immunocompetent bg/+ mice. Differences in susceptibility of bg/bg and bg/+ mice corresponded with temporal differences in histopathology. In contrast to bg/+ mice, inflammatory responses in infected tissues from bg/bg mice contained less cellular infiltrate, proportionally more polymorphonuclear neutrophils than monocytes and macrophages, and delays in the switch from acute to chronic inflammation. Enhanced growth of Cryptococcus neoformans in the internal organs of bg/bg mice was coincident with delayed inflammatory responses. These quantitative culture and histopathology studies suggest that the defects associated with monocytes and macrophages and polymorphonuclear neutrophils resulted in altered in vivo inflammatory responses and contributed to the enhanced susceptibility of beige mice to C. neoformans.     

Effects of probiotic bacteria on humoral immunity to Candida albicans in immunodeficient bg/bg-nu/nu and bg/bg-nu/+ mice

Germfree beige-nude ( bg/bg-nu/nu) and beige-heterozygous ( bg/bg-nu/+) mice were colonized with a pure culture of Candida albicans or with a probiotic bacterium (Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus casei, or Bifidobacterium infantis). Probiotic-colonized mice were subsequently challenged orally with C. albicans. The effect of prior colonization with probiotic bacteria on the antibody responses of the immunodeficient mice to alimentary tract colonization with C. albicans was compared to the antibody responses of the gnotobiotic mice colonized only with C. albicans. This study demonstrated that, although the probiotic bacteria did not induce a vigorous antibody response to their own antigens, they altered the antibody responses of mice to C. albicans. In T cell competent bg/bg-nu/+mice, B. infantis enhanced and focused IgG1, IgG2A, and IgA responses to C. albicans antigens. Some of the probiotic bacteria also enhanced the IgG1 and IgG2A antibody responses of bg/bg-nu/nu mice to C. albicans antigens. This study not only shows the value of gnotobiotic animal models in demonstrating that probiotic bacteria can affect the capacity of mice to form antibodies to C. albicans, but it also points out their usefulness in comparing the capacity of different probiotic bacteria to produce beneficial health effects in mice.     

Biotherapeutic effects of Bifidobacterium spp. on orogastric and systemic candidiasis in immunodeficient mice

Two commercially available Bifidobacterium spp. (Bifidobacterium infantis and Bifidobacterium lactis) were compared for their capacities to protect immunodeficient bg/bg-nu/nuand bg/bg-nu/+mice from orogastric and lethal candidiasis. Both Bifidobacterium spp. prolonged the survival of Candida albicans-colonized adult and neonatal bg/bg-nu/numice. The bifidobacteria affected the production of antibodies to C. albicans, inhibited disseminated candidiasis, suppressed weight loss associated with C. albicans infection, inhibited the growth of C. albicans in the alimentary tract, inhibited systemic candidiasis of endogenous origin, and decreased the severity of gastric candidiasis in both mouse strains. B. infantis inhibited systemic candidiasis of endogenous origin better than B. lactis; however, B. lactis was significantly more effective at inhibiting C. albicans colonization of the alimentary tract, suppressing gastric candidiasis, and protecting bg/bg-nu/numice from lethal candidiasis than B. infantis. These results show that Bifidobacterium spp. can protect immunodeficient mice from candidiasis but different species manifest quantitative and qualitative differences in their probiotic and biotherapeutic effects.     

The efficacy of biological response modifiers against murine cytomegalovirus infection in normal and immunodeficient mice

The host-mediated antiviral effect of two biological response modifiers (BRM), OK-432 and PS-K, against murine cytomegalovirus (MCMV) was evaluated in normal and immunologically deficient mice of the same litters. In normal littermate mice, BALB/c (nu/+) or C57BL/6 (bg/+), the BRM-induced resistance against MCMV infection was evidenced by increase in fifty percent lethal doses, decrease in titers of viruses replicated in the target organs and augmentation of natural killer (NK) cell activity of the spleen cells. In T cell-deficient, athymic nude mice, BALB/c (nu/nu), the protective effect was manifested by prolongation of the survival, decrease in the virus titers, and increase in the NK-cell activity, but without decrease in mortality. In NK cell-deficient, beige mutant mice, C57BL/6 (bg/bg), the BRM-induced protection was nullified or minimized, and there was little difference in those parameters between BRM-treated and untreated mice. However, with higher doses of OK-432, but not PS-K, or with sublethal doses of MCMV, the NK cell activity was slightly augmented in the beige mutant mice. Thus both NK cell and T cell activity are essential for mice to overcome acute MCMV infection and it is likely that the protective effect of BRM manifests itself fully, at least in immunologically intact mice.     

Aberrant T cells in beige mutant mice

Cytotoxic T lymphocyte (CTL) morphology and function was examined in beige (bg/bg) mutant mice during infection with lymphocytic choriomeningitis virus (LCMV). Virus-specific, class I-restricted CTL activity mediated by total spleen leukocytes isolated from bg/+ or +/+ mice on days 7 or 9 postinfection with LCMV was moderately higher than that mediated by spleen cells isolated from bg/bg mice. The CTL generated in bg/bg mice had aberrant morphology. Lyt-2+ cells isolated from bg/+ or +/+ mice had typical large granular lymphocyte (LGL) morphology and contained numerous small azurophilic granules, whereas Lyt-2+ cells isolated from bg/bg mice contained only one or two large atypical granules in their cytoplasm. Aberrant LGL morphology correlated with reduced lytic capacity. The bg/bg CTL were inefficient killer cells mediating, on a per cell basis, only one fourth of the lysis mediated by bg/+ CTL. The bg/bg mice appeared to mount a compensatory response to regulate virus replication, because frequencies of Lyt-2+ cells and cells that specifically bound to virus-infected target cells were elevated as compared with their frequencies in bg/+ mice. The higher proportion of the CTL phenotype cells appeared to be a consequence of expanded proliferation of Lyt-2+ cells. These results demonstrate that, in comparison with bg/+ and +/+ mice, bg/bg mice have CTL with reduced lytic capacities, but may compensate during virus infection by expanding the number of these cells. Furthermore, these data suggest that the depressed lytic activity may be a consequence of aberrant granule formation.     

Defense mechanisms of mice against Fonsecaea pedrosoi infection

Defense mechanisms of a host against Fonsecaea pedrosoi infection were studied histopathologically using athymic nude (nu/nu) mice of BALB/c background and their heterozygous (nu/+) littermates. Thirty male nu/nu and 30 nu/+ mice, weighing 16–19 g, were employed in this experiment. The nu/nu or nu/+ mice were divided into 3 groups consisting of 10 each. Furthermore, 4 nu/nu mice were supplemented to investigate effects of lymph node cell transfer. Subglobose cells of F. pedrosoi Tsuchiya strain were obtained from a culture in brain heart infusion glucose (1%) broth with reciprocal shaking at 37 °C for 17 days, and then 0.02, 0.1 and 0.5% cells suspensions were prepared. Each cell suspension was allotted to one group of the nu/nu or nu/+ mice. 0.1 ml of the cell suspension was inoculated into a tail vein, then one mouse from each group was sacrificed 1, 2, 4, 6, 8, 10, 14, 18, 21 and 25 days after inoculation. In both the nu/nu and nu/+ mice, the brain, kidneys and heart were affected severely with the strain in that order. Histopathologically, the defense mechanisms of the nu/+ mice against the fungus infection consisted chiefly of 2 steps: first, of non-immune phagocytosis by polymorphonuclear leucocytes (PMNs), and second, of granuloma formation induced by cell-mediated immunity. Those of the nu/nu mice consisted only of one step: phagocytosis by PMNs. A difference in susceptibility to the strain between the nu/nu and nu/+ mice changed according to the amount of the fungal cells inoculated. When inoculated with the 0.02% cell suspension, the resistance of the nu/nu mice was stronger than that of the nu/+ mice. In contrast, when inoculated with the 0.5% cell suspension, the former was affected more severely than the latter. There were little differences in the susceptibility to the strain between the nu/nu and nu/+ mice inoculated with the 0.1% cell suspension. These data seem to indicate that the phagocytic function of PMNs of the nu/nu mice was more active than that of the nu/+ mice, and the nu/nu mice inoculated with the 0.5% cells suspension (beyond the phagocytic capacity) lost resistance against the fungus infection. When the nu/nu mice were transferred with lymph node cells before inoculation of the strain, granulomata were formed to prevent hyphae from growing freely in the tissue.     

The C57BL/6 nude, beige mouse: a model of combined T cell and NK effector cell immunodeficiency

This article describes the construction and establishment of a double congenic nude, beige C57BL/6 (B6 nu, bg) mouse strain. The mice do not show higher fragility than C57BL/6 nude mice and the double congenic strain can be maintained under conventional mouse housing conditions. Although the B6 nu, bg display a very low natural killer activity which cannot be enhanced by an interferon inducer (poly(I-C], they lack responsiveness to a T cell mitogen (concanavalin A); and they also show extremely low responsiveness to a B cell mitogen (0128: B12 Escherichia coli lipopolysaccharide) probably as a result of combined effects of the beige and nude genes in the C57BL/6 genetic context.     

Enhanced human tumor cell transplantability in a new congenic immunodeficient mouse; KSN-BNX

We introduced two mutant genes (beige; bg that induces the deficiency of natural killer (NK) activity andxid that decreases the production of immunoglobulin) into KSN nude mice with high reproductive performances. We produced KSNbg/bg(nu/nu) (KSN-bg), KSN-xid/xid(nu/nn) (KSN-xid), KSNxid/xid;bg/bg(nu/nu) (KSN-BNX) and KSN-nu/+ (KS) mice by backcross (cross-intercross method). All strains showed as high a reproductivity rate as the parental KSN mice. KSN-xid and KSN-BNX mice had a reduced percentage of B220 positive cells in the spleens compared to KSN and KSN-bg mice, but they showed increased percentages, of Thy-1 and asialo GM1 positive cells. The serum immunoglobulin concentrations of KSN-BNX were as low as KSN-xid. Both KSN-bg and KSN-BNX mice showed deficient NK activity in spleens, whereas KSN-xid mice showed an elevated NK activity. Compared to nude mice, the growth of both human tumor cell TCO-1 and BxPc-3 transplanted subcutaneously was enhanced in KSN-BNX mice. However Panc-1 cells that was rejected in nude mice was not accepted in KSN-BNX mice. Liver metastasis of human pancreatic tumor cells; Capan-1, BxPc-3 and MIAPaCa-2 were studied. No significant difference was observed in the percentage of metastasis formed mice between nude and KSN-BNX mice.     

The SCID/Beige mouse as a model to investigate protection against Yersinia pestis

In this study, we have shown that severe combined immunodeficient/beige mice reconstituted with hyperimmune Balb/c lymphocytes can be used as a model to demonstrate adoptive and passive protection against plague infection. Reconstitution of severe combined immunodeficient/beige mice was successful in nine out of ten mice as demonstrated by spleen colonisation and sustained circulating immunoglobulin titres. Furthermore, an increase in antibody titre was evident after a booster immunisation of reconstituted mice. Presence of circulating antibody correlated with protection against a systemic plague challenge and indicated that in reconstituted mice adoptive transfer of a functional immune system had occurred. The severe combined immunodeficient/beige mouse was also used to demonstrate passive protection against inhaled and systemic plague infection. The reconstituted severe combined immunodeficient/beige mouse model demonstrating protective immunity against plague will be further developed to identify the immune cell subsets responsible for this protection.     

Immunologic homeostasis during infection: coexistence of strong pulmonary cell-mediated immunity to secondary Cryptococcus neoformans infection while the primary infection still persists at low levels in the lungs

Maintenance of immunity to persistent pathogens is poorly understood. In this study, we used a murine model of persistent pulmonary fungal infection to study the ongoing cell-mediated immune response. CBA/J mice with low-level persistent Cryptococcus neoformans infection had CD4+ T cells of effector memory phenotype present in their lungs. Although unable to eliminate the primary infection to sterility, these mice displayed hallmarks of immunologic memory in response to rechallenge with C. neoformans: 1) the secondary cryptococcal challenge was controlled much more rapidly, 2) the inflammatory response developed and resolved more rapidly, 3) CD4+ T and CD8+ T cell responses were higher in magnitude, and 4) effector cytokine production by T cells was greatly enhanced. Depletion of CD4+ T cells at the time of secondary challenge adversely affected clearance of C. neoformans from the lungs. These results demonstrate that persistent low-level infection with C. neoformans does not impair the cell-mediated response to the fungus. Although they are relatively free of overt disease, these mice can respond with a rapid secondary immune response if the burden of C. neoformans increases. These data support the concept that immunologically healthy individuals can maintain low numbers of cryptococci that can become a nidus for re-activation disease during immunodeficient states such as AIDS.     

Cancer induction by methylcholanthrene and metastatic spread of transplantable tumor in Chediak Higashi (beige) mice

Summary We compared the beige mouse (bg/bg) model of Chediak-Higashi syndrome to the phenotypically normal counterpart (bg/+) in their sensivity to tumor induction and growth. No differences were observed in the incidence or time of appearance of tumors nor in the time of death, in bg/bg or bg/+ injected with 0.1 mg 3 MCA. When grafted with the transplantable 3LL tumor, the tumor grew comparably at the graft site in both groups.Bg/bg mice did however, have significantly more lung metastases than bg/+ in some experiments. The intravenous injection of non-metastasizing B16 melanoma cells demonstrated that this difference was not due to variation in trapping of circulating tumor cells by the lung.     

Mycoplasma pulmonis Arthritis in Congenitally Athymic (Nude) Mice

Histopathological examinations were performed on arthritic joints and other organs of strain BALB/cA nu/nu and nu/+ mice intravenously injected with Mycoplasma pulmonis strain m53. In both groups of mice suffering from polyarthritis, acute inflammatory lesions with infiltration of polymorphonuclear leukocytes in the synovia and periarticular tissues were observed one to two weeks after injection. In nu/nu mice, the acute inflammation appeared repeatedly up to 20 weeks after inoculation, when the experiment was terminated, and furthermore, extensive synovial and periarticular necrosis were characteristically present after the 4th week. Only a small number of lymphocytes and plasma cells were in the lesions. In nu/+ mice, after the early acute inflammation of arthritis, relapses of the infiltration of polymorphonuclear leukocytes were also observed in some mice in and after the 10th week. In addition, infiltration of lymphocytes and plasma cells was substantial after the 15th week. Focal necrosis was sometimes found in the liver of nu/nu mice. Perivascular infiltration of small lymphocytes and plasma cells was found in the lungs, liver and kidney of nu/+ mice in and after the 15th week. Repair mechanisms of injured articular tissues in nu/nu mice were histopathologically poor, while those in nu/+ mice seemed to be progressive and quite similar to those reported by many investigators for mice with the thymus intact. The histopathological differences are discussed in respect to the thymus-dependent immune responses.     

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.     

Mycoplasma pulmonis arthritis in congenitally athymic (nude) mice. Clinical and biological features

Congenitally athymic BALB/cA nu/nu mice were employed to elucidate the role of the thymus in experimental Mycoplasma pulmonis strain m53 infection, and nu/+ mice were used for comparison. Chronic polyarthritis was frequently produced in both of nu/nu and nu/+ mice by intravenous injection of the organisms. Macroscopically, nu/nu mice developed severer arthritis and a much lower grade of resolution than nu/+ mice. Periarticular abscess, conjunctivitis, and emaciation were observed in some of the nu/nu mice, but not in the nu/+ mice. Mycoplasmas were isolated from joints and other tissues (including periarticular abscesses and eyelids) of infected nu/nu mice at higher frequencies as well as in greater quantities, and did not show any elimination trends for at least 20 weeks after inoculation. However, nu/+ mice, mycoplasmas were almost exclusively located in joints, and distribution of organisms to the other organs disappeared soon after the infection. Increases in complement-fixing antibody titers were not related to the inhibition of mycoplasmal spread. Thymus-dependent functions that may in some way prevent growth and spread of mycoplasmas in mice are discussed.     

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.     

Changes in proliferation activity and relative distributions of lymphoid cell subpopulations in congenitally athymic nu/nu mice and lurcher mice with spontaneous olivopontocerebellar degeneration

Changes observed in mice with congenital damage of some part of the CNS-neuroendocrine-immune regulatory system are described. nu/nu mice with congenital absence of thymus and Lurcher mice with spontaneous olivopontocerebellar degeneration displayed changes in the histoarchitecture of adrenal gland, immune organs (thymus, spleen, axillar lymph nodes) and intestine. Changes were also observed in IgM+, IgG+, CD4+ and CD8+ lymphoid cell subpopulations in the main lymphoid organs--the spleen and axillar lymph nodes and in the proliferative ability of whole lymphoid cell populations. The extreme decrease of lymphoid T-cell subpopulations in athymic nu/nu mice is the consequence of the absence of thymus, the organ of their maturation. On the other hand, a relative increase of B-cell subpopulations was found in this mouse strain. A relative decrease of CD4+ lymphocytes and a different influence of immunization on B-cell subpopulations were found in the spleen in neurodeficient Lurcher mice. The high percentage of apoptotic cells, cells in the S-phase of cell cycle and increased proliferation index in nu/nu mice suggest that the turnover and renewal of lymphoid cells in the spleen in nu/nu mice is more rapid than in control immunocompetent BALB/c mice.     

Ultrastructure of lung elastin and collagen in mouse models of spontaneous emphysema.

The tight-skin (Tsk) and beige (bg) mutants of the C57B1/6J strain of mouse spontaneously develop air-space enlargement reminiscent of human emphysema. To determine if this enlargement is accompanied by matrix destruction, as in the human disease, we examined the elastin and collagen matrices of the lungs of both mutants. The ultrastructure of these matrix components was separately visualized by scanning electron microscopy following controlled alkali digestion, which preserves collagen, and formic acid digestion, which enables visualization of elastin. Significant elastin destruction suggestive of an elastolytic process was observed in the lungs of Tsk mice. Thickening of elastin lamellae was observed in the lungs of bg mice, suggesting that congenital matrix remodeling may underlie air-space enlargement in this strain.     

Experimental study on the relapse of tuberculosis after the termination of antituberculous chemotherapy using immunodeficient nude mice.

The effect of cellular immunity induced by tuberculous infection on bacteriological relapse after the termination of antituberculous chemotherapy was studied experimentally using immunodeficient nu/nu mice and immunocompetent dd mice. The efficacy of intensive chemotherapy was excellent even in nu/nu mice; tubercle bacilli in the organs decreased below the detectable limit, but formidable regrowth of bacilli was seen after the termination of chemotherapy. On the other hand, in the case of dd mice that established antituberculous cellular immunity through tuberculous infection, bacteriological relapse was generally very slight. It was concluded that bacteriological relapse was related closely with the established cellular immunity induced by the infected tubercle bacilli.