Effects of bovine lactoferrin on the immune system and the intestinal microflora of adult dogs

Eighteen Beagle dogs were used to evaluate the effects of bovine lactoferrin (bLF) on immune function and faecal microbial populations. The study comprised three feeding periods, each lasting four weeks. After an initial control Period 1, six dogs per group were supplemented with 0, 120 and 1800 mg bLF/kg dry diet, respectively (Period 2). In Period 3 dogs received again control diets. Peripheral blood mononuclear cell subsets, lymphocyte proliferative response to concanavalin A, phytohaemagglutinin and pokeweed mitogen and plasma IgA and IgG concentrations were analysed. The faecal concentrations of aerobic and anaerobic bacteria, Escherichia coli, Clostridium perfringens, Lactobacillus spp. and Bifidobacterium spp. were determined by cultural methods. Supplementation of bLF increased the number of monocytes, T cells and cytotoxic T cells in the blood and the proliferative response of peripheral blood mononuclear cells. The leukocyte counts were not affected, except monocytes that increased after the supplementation with bLF. Plasma immunoglobulin concentrations were unchanged by treatment. Dogs supplemented with bLF tended to have lower faecal concentrations of E. coli and Clostridium perfringens. In conclusion, bLF seems to alter indices of the cellular immune response and faecal microbial populations of healthy adult dogs.     

Gastrointestinal and immunological responses of senior dogs to chicory and mannan-oligosaccharides

Thirty-four senior dogs (pointers 8 - 11 years, beagles 9 - 11 years) were used to evaluate the effects of oligosaccharides on nutritional and immunological characteristics. Dogs were randomly allotted to treatments [1% chicory (CH), 1% mannan-oligosaccharide (MOS), 1% chicory + 1% MOS (CM), or no supplementation (control, CON)] in a parallel design with a 4 week baseline period followed by a 4 week treatment period. Dietary supplementation with MOS or CM tended (P = 0.07) to increase food intake due, in part, to an increase in fermentable fibre and a decrease in energy content of the diet. Although wet faecal output increased (P < 0.05) for dogs supplemented with MOS or CM, when corrected for food intake, no differences were noted. The CM treatment increased (P < 0.05) faecal score (1 = hard and dry, 5 = watery liquid), although these scores remained in a desirable range (3 to 3.5). Chicory supplementation increased (P = 0.07) fat digestibility. Chicory or MOS increased (P  0.05) faecal bifidobacteria concentrations 0.4 and 0.5 log₁₀ cfu/g DM, respectively, compared to the CON, while MOS decreased (P < 0.05) faecal E. coli concentrations. Oligosaccharides did not affect white blood cell (WBC) concentrations, but CH and CM tended to increase (P = 0.10) neutrophil concentrations compared to control dogs. Peripheral lymphocyte concentrations were decreased in dogs supplemented with MOS (P = 0.06) and CM (P < 0.05). Chicory and MOS alter faecal microbial populations and certain indices of the immune system of senior dogs.     

Gastrointestinal and immunological responses of senior dogs to chicory and mannan-oligosaccharides

Thirty-four senior dogs (pointers 8-11 years, beagles 9-11 years) were used to evaluate the effects of oligosaccharides on nutritional and immunological characteristics. Dogs were randomly allotted to treatments [1% chicory (CH), 1% mannan-oligosaccharide (MOS), 1% chicory + 1% MOS (CM), or no supplementation (control, CON)] in a parallel design with a 4 week baseline period followed by a 4 week treatment period. Dietary supplementation with MOS or CM tended (P = 0.07) to increase food intake due, in part, to an increase in fermentable fibre and a decrease in energy content of the diet. Although wet faecal output increased (P < 0.05) for dogs supplemented with MOS or CM, when corrected for food intake, no differences were noted. The CM treatment increased (P < 0.05) faecal score (1 = hard and dry, 5 = watery liquid), although these scores remained in a desirable range (3 to 3.5). Chicory supplementation increased (P = 0.07) fat digestibility. Chicory or MOS increased (P < or = 0.05) faecal bifidobacteria concentrations 0.4 and 0.5 log10 cfu/g DM, respectively, compared to the CON, while MOS decreased (P < 0.05) faecal E. coli concentrations. Oligosaccharides did not affect white blood cell (WBC) concentrations, but CH and CM tended to increase (P = 0.10) neutrophil concentrations compared to control dogs. Peripheral lymphocyte concentrations were decreased in dogs supplemented with MOS (P = 0.06) and CM (P < 0.05). Chicory and MOS alter faecal microbial populations and certain indices of the immune system of senior dogs.     

Effects of a probiotic Lactobacillus acidophilus strain on feed tolerance in dogs with non-specific dietary sensitivity

This study investigated the effects of the probiotic Lactobacillus acidophilus strain DSM 13241 in dogs with non-specific dietary sensitivity (NSS). Six adult German Shorthair Pointers with NSS consecutively received a control dry diet and the same diet supplemented with the probiotic (6 x 10(6) cfu/g) for 12 weeks each, followed by another control period of four weeks. Frequency of defecations, faecal quality and nutrient digestibility were determined. Faeces were cultured for Clostridium perfringens, Escherichia spp., lactobacilli and bifidobacteria and quantitative fluorescence in situ hybridisation (FISH) was performed. Feeding the probiotic improved faecal consistency, faecal dry matter and defecation frequency (p < 0.05). Faecal concentrations of culturable lactobacilli and bifidobacteria increased numerically, but not significantly, also the decrease of the numbers of C. perfringens and Escherichia spp. did not reach the level of significance. Results from FISH showed more constant bacterial populations. It can be concluded that L. acidophilus DSM 13241 can stabilise the digestive processes in dogs with NSS.     

Escherichia coli and enterococci are sensitive and reliable indicators for human,livestock and wildlife faecal pollution in alpine mountainous water resources

Aims: This study evaluated the applicability of standard faecal indicator bacteria (SFIB) for alpine mountainous water resources monitoring. Methods and Results: Escherichia coli, enterococci (ENTC) and Clostridium perfringens were investigated by standard or frequently applied phenotypic and genotypic methods in a broad range of animal and human faecal sources in a large alpine mountainous area. Clostridium perfringens occurred only in human, livestock and carnivorous source groups in relevant average concentrations (log 4·7–7·0 CFU g^?1) but not in herbivorous wildlife sources. Escherichia coli proved to be distributed in all faecal source groups with remarkably balanced average concentrations (log 7·0–8·4 CFU g^?1). Except for single faecal samples from the cattle source group, prevalence rates for ENTC source groups were generally >87% with average concentrations of log 5·3–7·7 CFU g^?1. To test the faecal indication capacity in the environment, faecal prevalence data were comparatively analysed with results from the concurrently performed multi‐parametric microbial source tracking effort on karst spring water quality from the investigated alpine mountainous catchment ( Reischer et al. 2008 ; Environ Microbiol 10:2598–2608). Conclusion: Escherichia coli and enterococci are reliable faecal indicators for alpine mountainous water resources monitoring, although E. coli is the more sensitive one. Clostridium perfringens did not prove to be an indicator of general faecal pollution but is suggested a conservative microbial source tracking marker for anthropogenic faecal influence. Significance and Impact of the Study: Applicability of SFIB is currently hotly debated. This is the first study providing comprehensive information on the applicability of SFIB at alpine mountainous habitats.     

Cytomegalovirus infection of peripheral blood mononuclear cells: effects on interleukin-1 and -2 production and responsiveness.

Cytomegalovirus suppresses the proliferative response of peripheral blood mononuclear cells to phytohemagglutinin. In these experiments, we identified which mononuclear cell subpopulation might be responsible for the suppression. We found that prior infection of either lymphocytes or monocytes followed by reconstitution with monocytes or lymphocytes, respectively, would abrogate the proliferative response in a subsequent culture with phytohemagglutinin. Infection of either cell type also reduced both the production of interleukin-1 (IL-1) and IL-2 and the proliferative response to exogenously supplied IL-1 or IL-2. We did not find evidence for an IL-2 antagonist. These experiments suggest that cytomegalovirus causes a metabolic derangement in lymphocytes and monocytes and impairs their ability both to produce and to respond to physiological mediators of the immune response.     

The immunosuppressive activities of newly synthesized azaphenothiazines in human and mouse models

In this study, we evaluated the activities of new types of azaphenothiazines in the following immunological assays: the proliferative response of human peripheral blood mononuclear cells induced by phytohemagglutin A or anti-CD3 antibodies; lipopolysaccharide-induced cytokine production by human PBMC; the secondary, humoral immune response in mice to sheep erythrocytes (in vitro); and delayed-type hypersensitivity in mice to ovalbumin (in vivo). In some tests, chlorpromazine served as a reference drug. The compounds exhibited differential inhibitory activities in the proliferation tests, with 10H-2,7-diazaphenothiazine (compound 1) and 6-(3-dimethylaminopropyl)diquinothiazine (compound 8) being most suppressive. Compound 1 was selected for further studies, and was found to be strongly suppressive in the humoral immune response even at low concentrations (1 μg/ml). Compound 1 also inhibited the delayed-type hypersensitivity lipopolysaccharide-induced production of tumor necrosis factor and interleukin-6 in cultures of human blood cells. As there were only two subjects in this study, the effects of these compounds on human blood cells need to be confirmed. In this paper, we also discuss the structure-activity relationships of selected compounds.     

Effects of lactoferrin supplementation on ileal and total tract nutrient digestibility, gastrointestinal microbial populations, and immune characteristics of ileal cannulated, healthy, adult dogs

Orally supplemented lactoferrin derived from bovine milk is purported to have beneficial effects on gut health of animals. Bovine lactoferrin (0, 60, or 120 mg/d) was fed to ileal cannulated, adult dogs in a replicated 3 x 3 Latin square design with 14 d periods. Control dogs tended (p = 0.06) to have higher fecal DM concentrations compared with dogs supplemented with 120 mg/d lactoferrin (34.5 vs. 32.9%). Fecal scores ranged from 3.0 - 3.3, suggesting that feces of all dogs was near the desired consistency, with dogs supplemented with 120 mg/d lactoferrin tending (p = 0.08) to have higher fecal scores. Ileal azoreductase activity tended (p < 0.10) to be higher in dogs supplemented with 60 or 120 mg/d lactoferrin (609 vs. 592 nmol/h per g ileal DM, respectively) as compared with unsupplemented dogs (272 nmol/h per g ileal DM). The following bacterial groups were measured: bifidobacteria, Campylobacter spp., Clostridium spp., eubacteria, Escherichia coli, Lactobacillus spp., Staphylococcus spp., and Streptococcus spp. Fecal streptococci concentrations were lower (p < 0.05) for dogs receiving 60 mg/d lactoferrin (8.60 log10 cfu/g fecal DM) as compared with unsupplemented dogs (9.19 log10 cfu/g fecal DM) or dogs receiving 120mg lactoferrin/d (9.43 log10 cfu/g fecal DM). Dogs supplemented with 120mg/d lactoferrin tended (p = 0.08) to have higher fecal indole concentrations as compared to unsupplemented dogs (1.80 vs. 1.46 micromol/g fecal DM). Because most bacterial groups measured were unaffected, it appears that lactoferrin did not exhibit prebiotic activity, and based on the data collected, lactoferrin also did not appear to have major effects on indices of health in the dog.     

Mulberry juice freeze-dried powder attenuates the disease severity by the maintaining of colon mucosa in mice with DSS-induced acute colitis

This study aimed to evaluate the microbial compositions and gene expression related to inflammation in dextran sodium sulfate (DSS)-induced acute colitis and the effect of mulberry supplementation. Male BALB/c mice received a diet supplemented with mulberry juice freeze-dried powder (MFP) or not for 3 weeks. After 3 weeks, the mice received water containing 5% (w/v) DSS or not for 1 week. The disease activity index score in mice fed MFP was significantly decreased. A significant decrease in Bifidobacterium spp. and the Clostridium perfringens subgroup was observed in mice not fed MFP. The number of goblet cell and NLRP6 expression were observed in mice fed a diet supplemented with MFP compared with mice not fed MFP. These results may indicate that mulberry mitigates DSS-induced acute colitis by a changing the gut microbial flora and by improving mucosal conditions.     

Increased Escherichia coli-Induced Interleukin-23 Production by CD16+ Monocytes Correlates with Systemic Immune Activation in Untreated HIV-1-Infected Individuals

The level of microbial translocation from the intestine is increased in HIV-1 infection. Proinflammatory cytokine production by peripheral antigen-presenting cells in response to translocated microbes or microbial products may contribute to systemic immune activation, a hallmark of HIV-1 infection. We investigated the cytokine responses of peripheral blood myeloid dendritic cells (mDCs) and monocytes to in vitro stimulation with commensal enteric Escherichia coli in peripheral blood mononuclear cells (PBMC) from untreated HIV-1-infected subjects and from uninfected controls. Levels of interleukin 23 (IL-23) produced by PBMC from HIV-1-infected subjects in response to E. coli stimulation were significantly higher than those produced by PBMC from uninfected subjects. IL-23 was produced primarily by CD16⁺ monocytes. This subset of monocytes was increased in frequency and expressed higher levels of Toll-like receptor 4 (TLR4) in HIV-1-infected individuals than in controls. Blocking TLR4 on total CD14⁺ monocytes reduced IL-23 production in response to E. coli stimulation. Levels of soluble CD27, an indicator of systemic immune activation, were elevated in HIV-1-infected subjects and were associated with the percentage of CD16⁺ monocytes and the induction of IL-23 by E. coli, providing a link between these parameters and systemic inflammation. Taken together, these results suggest that IL-23 produced by CD16⁺ monocytes in response to microbial stimulation may contribute to systemic immune activation in HIV-1-infected individuals.     

Imaging reactive oxygen species in asthma

Inflammatory processes in asthma are characterized by an infiltration of inflammatory cells including mononuclear phagocytes. It has been observed that mononuclear phagocytes, alveolar macrophages and blood monocytes, release higher quantities of reactive oxygen species in asthmatic patients than in healthy subjects. Chemiluminescence assays were developed to measure the superoxide anion and the other reactive oxygen species. The chemiluminescence response was first analysed with a luminometer, which made it possible to study cells in suspension before and after PMA-stimulation. Secondly a video-imaging camera was used in experiments on adherent cells before and after stimulation with PMA and/or specific stimulus IgE/anti-IgE. Both techniques showed that human alveolar macrophages, blood monocytes, PMN and lymphocytes were spontaneously primed in vivo and were more easily stimulated in asthma. Analysis of adherent cells in vitro may provide give information on the physiological condition of adherent cells in vivo.     

Single-cell RNA sequencing reveals transcriptional profiles of monocytes in HBV-infected pregnant women during mid-pregnancy

There is a growing body of evidence that innate immunity also plays an important role in the progression of hepatitis B virus (HBV) infection. However, there is less study on systematically elucidating the characteristics of innate immunity in HBV-infected pregnant women. We compared the features of peripheral blood mononuclear cells in three healthy pregnant women and three HBV-infected pregnant women by single-cell RNA sequencing. 10 DEGs were detected between groups and monocytes were the main expression source of most of the DEGs, which involved in the inflammatory response, apoptosis and immune regulation. Meanwhile, qPCR and ELISA were performed to verify above genes. Monocytes displayed immune response defect, reflecting poor ability of response to IFN. In addition, eight clusters were identified in monocytes. We identified molecular drivers in monocytes subpopulations.TNFSF10+ monocytes, MT1G+ monocytes and TUBB1+ monocytes were featured with different gene expression pattern and biological function.TNFSF10+ monocytes and MT1G+ monocytes were characterized by high levels of inflammation response.TNFSF10+ monocytes, MT1G+ monocytes and TUBB1+ monocytes showed decreased response to IFN. Our results dissects alterations in monocytes related to the immune response of HBV-infected pregnant women and provides a rich resource for fully understanding immunopathogenesis and developing effective preventing HBV intrauterine infection strategies.     

Cellular requirements for lymphocyte restimulation after a first challenge in vitro.

Human peripheral blood lymphocytes from donors who were sensitized in vivo to bacterial antigens were stimulated by these antigens in vitro. When the cells from these first cultures were challenged with irradiated allogeneic lymphocytes, a proliferative response was obtained, the kinetics of which resembled those of a primary mixed lymphocyte reaction (MLR). On the other hand, the addition, under these conditions, of bacterial antigens never led to any second proliferative response. It was shown that: (1) the addition of irradiated autologous mononuclear cells, together with the bacterial antigens, led to a reconstitution of a proliferative response in second culture; (2) the cells capable of reconstituting the reactivity to tetanus toxoid could also be obtained from donors whose own cells did not respond to that antigen in primary cultures, and (3) the reconstituting activity in the second culture could not be provided by monocytes alone.     

Changes in bacterial populations in the ileum of pigs fed low-phosphorus diets supplemented with different sources of fermentable carbohydrates

An experiment was conducted to evaluate the effects of differently fermentable carbohydrates on changes in bacterial populations in the ileum of growing pigs fed low-phosphorus (P) diets. Eight barrows (mean surgery BW 36 ± 0.9 kg) were fitted with simple T-cannulae at the distal ileum and were assigned to one of four dietary treatments: maize-soybean meal based control diet (CD), or 0.75 of CD supplemented with 0.25 lignocellulose, maize starch and high-methylated apple-pectin, respectively. Total bacterial cell counts as well as cell counts of Lactobacillus spp., Lactobacillus reuteri, Lactobacillus amylovorus/Lactobacillus sobrius, Lactobacillus mucosae, Enterococcus spp., Enterococcus faecium, Enterococcus faecalis, bifidobacteria, Clostridium coccoides cluster, Clostridium leptum cluster, Bacteroides–Prevotella–Porphyrmonas group and Enterobacteriaceae were determined by quantitative realtime PCR in DNA extracts of ileal digesta. Denaturing gradient gel electrophoresis (DGGE) of DNA fragments, generated by PCR targeting total or Lactobacillus spp. 16S rDNA, was used to estimate the bacterial diversity in the ileum. Lignocellulose supplementation tended (P<0.1) to increase cell counts of total bacteria in faeces compared with the control. Ileal bacterial populations responded differently to carbohydrate addition. Maize starch supplementation strongly stimulated the growth of total lactobacilli and Lactobacillus species (P≤0.05). Lignocellulose, in turn, enhanced the numbers of bifidobacteria, but reduced those of L. amylovorus compared with the control (P<0.05). Finally, pectin tended to increase the cell numbers of L. amylovorus/L. sobrius and the Bacteroides–Prevotella–Porphyrmonas group compared with the control (P<0.1). DGGE analysis revealed increased band numbers for total bacteria in the ileum of animals fed the lignocellulose and maize starch supplemented diets, while pectin reduced total bacterial (P<0.1) and Lactobacillus spp. diversity (P<0.05) compared with the control, as determined with the Shannon's index. Ileal VFA concentrations were decreased by pectin, while lignocellulose decreased faecal VFA concentrations. In conclusion, ileal bacterial populations and diversity are susceptible to changes in the carbohydrate composition of the diet. However, these changes were not related to major differences in the number of total bacteria in ileal digesta and faeces, but rather to changes in the bacterial species composition and their metabolic activity.     

Effects of lactoferrin supplementation on ileal and total tract nutrient digestibility,gastrointestinal microbial populations,and immune characteristics of ileal cannulated,healthy, adult dogs

Abstract

Orally supplemented lactoferrin derived from bovine milk is purported to have beneficial effects on gut health of animals. Bovine lactoferrin (0, 60, or 120 mg/d) was fed to ileal cannulated, adult dogs in a replicated 3 × 3 Latin square design with 14 d periods. Control dogs tended (p = 0.06) to have higher fecal DM concentrations compared with dogs supplemented with 120 mg/d lactoferrin (34.5 vs. 32.9%). Fecal scores ranged from 3.0 – 3.3, suggesting that feces of all dogs was near the desired consistency, with dogs supplemented with 120 mg/d lactoferrin tending (p = 0.08) to have higher fecal scores. Ileal azoreductase activity tended (p < 0.10) to be higher in dogs supplemented with 60 or 120 mg/d lactoferrin (609 vs. 592 nmol/h per g ileal DM, respectively) as compared with unsupplemented dogs (272 nmol/h per g ileal DM). The following bacterial groups were measured: bifidobacteria, Campylobacter spp., Clostridium spp., eubacteria, Escherichia coli, Lactobacillus spp., Staphylococcus spp., and Streptococcus spp. Fecal streptococci concentrations were lower (p < 0.05) for dogs receiving 60 mg/d lactoferrin (8.60 log₁₀ cfu/g fecal DM) as compared with unsupplemented dogs (9.19 log₁₀ cfu/g fecal DM) or dogs receiving 120 mg lactoferrin/d (9.43 log₁₀ cfu/g fecal DM). Dogs supplemented with 120 mg/d lactoferrin tended (p = 0.08) to have higher fecal indole concentrations as compared to unsupplemented dogs (1.80 vs. 1.46 μmol/g fecal DM). Because most bacterial groups measured were unaffected, it appears that lactoferrin did not exhibit prebiotic activity, and based on the data collected, lactoferrin also did not appear to have major effects on indices of health in the dog.     

Distinctive functional properties of human blood L lymphocytes: a comparison with T lymphocytes, B lymphocytes, and monocytes.

Human blood lymphocytes with high affinity Fc receptors have been operationally named L lymphocytes because of membrane-labile IgG markers. L lymphocytes lack membrane-incorporated immunoglobulin and do not form rosettes with sheep red blood cells coated with IgM antibody and mouse complement. These lymphocytes are capable of binding IgG in normal human serum at 4 degrees C and will form rosettes with human lymphocytes coated with Ripley IgG. In this study, functional in vitro properties of isolated L lymphocytes were compared with T lymphocytes, B lymphocytes, and monocytes. To obtain these mononuclear populations, first, plastic adherent monocytes were harvested. T lymphocytes were then isolated by centrifugation of E rosette-forming cells, and other rosetting techniques were employed to isolate L and B lymphocytes by negative selection. The functional properties of L lumphocytes were completely unlike those of T cells, B cells, or monocytes. L lymphocytes did not proliferate in response to mitogens, soluble antigens, or cell surface antigens. Moreover, this population could not replace monocytes in helping T lymphocytes respond to concanavalin A and pokeweed mitogen. Once T cells were supplemented with monocytes, however, the addition of L lymphocytes to the culture greatly enhanced the T lymphocytes proliferative response to phytohemagglutinin, concanavalinA, purified protein derivative (PPD), and streptokinase/streptodornase. L lymphocytes were not a subset of B cells. They did not spontaneously develop surface Ig in culture, and pokeweek mitogen could not induce them to transform and generate cytoplasmic Ig detectable by immunofluorescence. Mixtures of B cells and T cells responded to pokeweed mitogen better than do T cells alone. In contrast, enhanced reactivity with L and T cell combinations was not observed. Another sharp difference between these two populations was the stimulator capacity of each in mixed lymphocyte culture. When B and L lymphocytes were carefully monocyte-depleted, only B cells were effective stimulators of autologous and allogeneic lymphocytes. In comparison with T cells, B cells, and monocytes, L lymphocytes were the only effective killers of human blood lymphocytes sensitized with IgG. L lymphocytes, then, have cytotoxic potential, but cannot proliferate in response to various stimulants or become antibody-producing cells. These findings suggest that L lymphocytes comprise a third lymphocyte population.     

Characterization of the natural immune response of rhesus monkey CD4+ve T cells to the bacterial antigen streptolysin O (SLO)

Abstract: Rhesus monkeys show a high proliferative T cell response to the bacterial exotoxin SLO without prior immunization. The present study was undertaken to characterize this naturally present SLO-responsiveness with particular emphasis on CD4^+ve reactive T cells. It is demonstrated that the frequency of SLO-reactive cells in the circulation ranges between 1 in 75 and 1 in 610 CD4^+ve T cells as determined with limiting dilution analysis. It is also shown that induction of a good proliferative response requires Mhc-DR matching between T cell and the antigen presenting cells (APC). Stable and DR-restricted SLO-specific CD4^+ve T cell lines were generated from CD8 depleted peripheral blood mononuclear cells (PBMC). The SLO-reactive CD4^+ve cell lines are tentatively characterized as Thl-like based on the predominant production of interferon-gamma (IFN-γ) over IL-4, although this seems contradicted by the IL-4 dependent growth of the lines.     

Influence of supplemental high molecular weight pullulan or γ-cyclodextrin on ileal and total tract nutrient digestibility,fecal characteristics,and microbial populations in the dog

Abstract

This study was conducted to determine if supplemental pullulan and γ-cyclodextrin affect canine nutrient digestibility, microbial populations, and fecal characteristics. Ileal cannulated dogs were fed a commercial diet, and treatments were administered daily in a 5×5 Latin square design: (i) no supplement; (ii) 2 g pullulan; (iii) 4 g pullulan; (iv) 2 g γ-cyclodextrin; (v) 4 g γ-cyclodextrin. Ileal and fecal samples were collected the last 4 d of each 14-d period. Increasing pullulan tended (p < 0.10) to linearly increase ileal bifidobacteria and lactobacilli and quadratically increase fecal lactobacilli. A similar response was noted in ileal bifidobacteria and lactobacilli with γ-cyclodextrin. γ-Cyclodextrin resulted in a quadratic decrease (p < 0.05) in fecal Clostridium perfringens. Increasing pullulan linearly increased (p < 0.05) fecal score, while γ-cyclodextrin resulted in a linear decrease (p < 0.05). Pullulan and γ-cyclodextrin supplementation may have beneficial effects on the microbial ecology of dogs.     

Differences in cellular immune response to l-glutamic acid60, l-alanine30, l-tyrosine10 (GAT) in full sibling embryo transfer cattle: Examination of requirements for cell proliferation

Pairs of full sibling embryo transfer cattle that expressed identical MHC class I and II products were tested for their in vitro proliferative response to GAT. Peripheral blood mononuclear cells from these cattle were either high or low responders to GAT. Cells from certain pairs of MHC identical siblings gave opposite responses. Low responder animals were further tested to determine if they might respond to GAT with different kinetics, with secondary in vitro restimulation, or with exogenous help provided by interleukin 2. Also, the role of antigen presenting cells and suppressor T cells from low responder animals was investigated. Using appropriate in vitro conditions, cells from all animals tested could respond to GAT. However, MHC identical animals tested under similar conditions exhibited differences in their response to GAT which suggests the proliferative immune response was influenced by factors in addition to MHC coded products.     

Isolation of human mononuclear cell subsets by counterflow centrifugal elutriation (CCE): II. Functional Properties of B-lymphocyte-, T-lymphocyte-, and monocyte-enriched fractions

Counterflow centrifugal elutriation (CCE), a technique which separates cells by size and density, was used to separate human peripheral blood mononuclear cells into fractions enriched for T lymphocytes, B lymphocytes, and monocytes. These morphologically and phenotypically distinct fractions were analyzed for their ability to respond in several functional assays. B-Cell-enriched fractions devoid of monocytes did not proliferate nor produce significant quantities of lymphokines in response to antigens. These B cells did proliferate to anti-IgM antibodies but not to anti-IgD antibodies. B-Cell fractions served as stimulators of the autologous mixed-lymphocyte reaction (AMLR). T-Lymphocyte fractions were unable to respond to antigen challenge, but both proliferation and lymphokine production could be restored by the addition of monocytes. Monocyte fractions produced PGE₂, displayed chemotaxis, and functioned as stimulators in the AMLR. Thus, CCE appears to be a useful technique for reproducibly obtaining highly enriched subsets of human peripheral blood mononuclear cells with unique phenotypic and functional properties. These isolated populations can consequently be used to identify the independent and collaborative roles of the cells in immunological events.