Intracellular Bacterial Diseases Research Articles

A pseudomolecule assembly of the Rocky Mountain elk genome.

Rocky Mountain elk (Cervus canadensis) populations have significant economic implications to the cattle industry, as they are a major reservoir for Brucella abortus in the Greater Yellowstone area. Vaccination attempts against intracellular bacterial diseases in elk populations have not been successful due to a negligible adaptive cellular immune response. A lack of genomic resources has impeded attempts to better understand why vaccination does not induce protective immunity. To overcome this limitation, PacBio, Illumina, and Hi-C sequencing with a total of 686-fold coverage was used to assemble the elk genome into 35 pseudomolecules. A robust gene annotation was generated resulting in 18,013 gene models and 33,422 mRNAs. The accuracy of the assembly was assessed using synteny to the red deer and cattle genomes identifying several chromosomal rearrangements, fusions and fissions. Because this genome assembly and annotation provide a foundation for genome-enabled exploration of Cervus species, we demonstrate its utility by exploring the conservation of immune system-related genes. We conclude by comparing cattle immune system-related genes to the elk genome, revealing eight putative gene losses in elk.

The Effect of Transfer Factor as Immunoprotective in Mice Challenged with <i>Mycobacteriu</i>m <i>tuberculosis</i>

Background: Transfer Factor (TF) is an immune modulator which stimulates the cellular arm of the immune system (killer lymphocytes), activates immune cytokine synthesis and regulates immune function [1]. TF is very effective in those diseases in which CMI plays a relevant role in protection and control of the disease, such as intracellular bacterial diseases (tuberculosis) [2]. TF are low molecular weight products from immune cells that are able to transmit the ability to express delayed-type hypersensitivity (DTH) and cell mediated immunity (CMI) from sensitized donors to non immune recipients [3]. Objectives: The aim of this experimental study is to determine the protective efficacy of transfer factor (TF) as immunotprotective for mice. Materials and methods: A total number of 82 mice were examined for their immunopotency and protective efficacy of Transfer factor (TF) against challenge dose of M. tuberculosis (107 CFU). A number of 20 mice were immunized with the attenuated strain of M. bovis, Bacillus Calmette-Guerin (BCG). After 21 days of BCG spleens of 10 tuberculous mice were removed aseptically for the preparation of TF. To evaluate the effect of TF 3 groups of inbred BALB/c male mice were injected with TF and challenged with virulent M. tuberculosis, All mice with TF were tested for tuberculin skin test (TST) so as to determine susceptibility and resistance against tuberculosis, susceptible groups of mice were challenged with virulent M. tuberculosis.Followed by study of humoral response by immunization of a group of mice with immune sera and challenged with M. tuberculosis H37Rv strain. Followed by an experiment of group A and B for the susceptibility and resistance of the strains of mice. Results: After three weeks of observations the mice of experiment were tested for tuberculin skin test and the results were positive. Effectiveness determination of TF as protective efficacy was (83.3%). Humoral immunity response against M. tuberculosis showed negative reaction hence mortality rate was 100%, group B mice were resistant for BCG (Swiss white strain). Conclusions: The results indicated that administration of murine transfer factor (mTF) extracted and prepared from spleen of animal model (mice) as immunoprotective for challenged mice of M. tuberculosis (H37Rv) showed a better results enhanced immune response in respect to delayed type hypersensitivity, survival rate and mortality rate suggesting that efficacy of mTF as immunotherapy for tuberculosis.

The effect of Transfer Factor as Immunotherapy comparing with the effect of BCG in Mice challenged with Mycobacterium tuberculosis

Background: Transfer Factor (TF) is an immune modulator which stimulates the cellular arm of the immune system (killer lymphocytes), activates immune cytokine synthesis and regulates immune function (Lawrence, 1955).TF is very effective in those diseases in which CMI plays a relevant role in protection and control of the disease, such as intracellular bacterial diseases (tuberculosis). ( Estrada Parra, et al1955). TF are low molecular weight products from immune cells that are able to transmit the ability to express delayed-type hypersensitivity (DTH) and cell mediated immunity (CMI) from sensitized donors to non immune recipients (Kirkpatrick, 2000). Objectives: The aim of this experimental study is to determine the protective efficacy of transfer factor (TF) as immunotherapy for mice in comparison to BCG. Materials and methods: A total number of 102 mice were examined for their immunopotency and protective efficacy of Transfer factor (TF) comparing to the protective efficacy of BCG single and second repeated dose against challenge dose of M. tuberculosis (107 CFU) . A number of 20 mice were immunize with the attenuated strain of M. bovis, Bacillus Calmette-Guerin (BCG). After 21 days of BCG spleens of 10 tuberculous mice were removed aseptically for the preparation of TF. To evaluate the effect of TF 3 groups of inbred BALB/c male mice were injected with TF and challenged with virulent M. tuberculosis, followed by another 3 groups of inbred BALB/c male mice which were immunized with BCG single and second repeated dose. All mice with BCG and TF were tested for tuberculin skin test (TST) so as to determine susceptibility and resistance against tuberculosis, susceptible groups of mice were challenged with virulent M. tuberculosis. Followed by study of humoral response by immunization of a group of mice with immune serum and challenged with M. tuberculosis H37Rv strain. Followed by an experiment of group A and B for the susceptibility and resistance of the strains of mice. A group of dead mice For histological study of the infected lungs were examined. Results:After three weeks of observations the mice of experiment(1) were tested for tuberculin skin test and the results were positive. Effectiveness determination of TF as protective efficacy was (83.3%). while effectiveness determination and protective efficacy of BCG first dose and boosting dose were (50%) and (70%) respectively. Humoral immunity response against M. tuberculosis showed negative reaction hence mortality rate was 100%, group B mice were resistant for BCG (Swiss white strain) and the results of histological study of the infected lungs showed lung bacilli that was M. tuberculosis. Conclusions: The results indicated that administration of murine transfer factor (mTF) extracted and prepared from spleen of animal model (mice) as immunotherapy for challenged mice of MTB (H37Rv) showed a better results enhanced immune response in respect to delayed type hypersensitivity , survival rate and mortality rate suggesting that efficacy of mTF as immunotherapy for tuberculosis. Repeat dose of BCG enhanced immune response in respect to delayed type hypersensitivity , survival rate (70%) and mortality rate (30%), suggesting that efficacy of BCG vaccine may improve and give better results if booster doses are given.

Exploring the Serine Protease Involved in Cell‐mediated Immunity in Fish

Viral and intracellular bacterial diseases are big problem in aquaculture. Defense against these diseases is largely dependent on cell‐mediated immunity in which cytotoxic T lymphocytes and NK cells play major roles. These cells kill cellular targets via either of two pathways, i.e. secretary (e.g. perforin/granzyme) and non‐secretary (e.g. Fas/FasL) one. In fish, biochemical mechanisms of the killing remain unknown. Here we tried to identify the protease involved in the killing adopting ginbuna crucian carp which has been used as a nice model for cell‐mediated immunity in fish. In order to identify the protease involved in the killing of allogeneic target cells, we performed cytotoxicity assays in the presence of serine or cysteine protease inhibitors using lymphocytes of ginbuna. Cytotoxicity was completely inhibited by the serine protease inhibitor “DCI”. By contrast cytotoxicity was partially inhibited with cysteine protease inhibitor, E‐64d. These findings suggest that serine proteases play a major role in the killing of target cells. We further analyzed the substrate specificity of the protease involved in cytotoxicity. Protease activity of lymphocyte lysate was enhanced by allo‐sensitization when Ac‐IETD‐MCA, Bz‐R‐MCA, Z‐GPR‐MCA, K‐MCA, and Suc‐AAPF‐MCA were used as substrates. To classify the group of protease involved in the cytotoxicity, protease inhibitor was added in enzyme assay. Serine protease inhibitor “AEBSF” completely inhibited enzyme activity only when Z‐GPR‐MCA was used. Furthermore, there was no inhibition with cysteine protease inhibitor “E‐64”. These results suggest that the serine protease which cleaves Z‐GPR‐MCA is involved in cytotoxicity.

Variations in Equid SLC11A1 (NRAMP1) Genes and Associations with Rhodococcus equi Pneumonia in Horses

Rhodococcus equi is an important intracellular pathogen of horses, most commonly causing chronic, suppurative bronchopneumonia in foals. Although most foals likely are exposed to environmental R equi within the 1st few days of life, only some develop R equi pneumonia, and the basis of differences in susceptibility among foals currently is unknown. In this study, we investigated solute carrier family 11 member 1 (SLC11A1) gene sequences in the 5' untranslated region, exon 1, and a portion of intron 1 for variations in 3 equid species (horse, donkey, zebra) and compared variants within 3 independent horse breeding farms for associations with R equi pneumonia by use of an age‐matched case‐control design. Seven novel variants in the 5' untranslated region were identified as specific for one or both of the non‐horse equid species sampled. In addition, a single novel horse variant in the 5' untranslated region, ‐57C/T, was identified in 4 breeds. The ‐57C/T variant was found on 2 of the 3 farms with endemic R equi pneumonia, representing 2 different horse breeds. Significant allelic and genotypic associations with susceptibility to R equi pneumonia were observed for the ‐57C/T variant in foals from these farms. Although the functional impact of this novel variant remains to be determined, this study represents an important step in our understanding of natural resistance to R equi foal pneumonia and other intracellular bacterial diseases affecting equids.

Variations in Equid SLC11A1 (NRAMP1) Genes and Associations with Rhodococcus Equi Pneumonia in Horses

Rhodococcus equi is an important intracellular pathogen of horses, most commonly causing chronic, suppurative bronchopneumonia in foals. Although most foals likely are exposed to environmental R. equi within the 1st few days of life, only some develop R. equi pneumonia, and the basis of differences in susceptibility among foals currently is unknown. In this study, we investigated solute carrier family 11 member 1 (SLC11A1) gene sequences in the 5' untranslated region, exon 1, and a portion of intron 1 for variations in 3 equid species (horse, donkey, zebra) and compared variants within 3 independent horse breeding farms for associations with R. equi pneumonia by use of an age-matched case-control design. Seven novel variants in the 5'untranslated region were identified as specific for one or both of the non-horse equid species sampled. In addition, a single novel horse variant in the 5'untranslated region, -57C/T, was identified in 4 breeds. The -57C/T variant was found on 2 of the 3 farms with endemic R. equi pneumonia, representing 2 different horse breeds. Significant allelic and genotypic associations with susceptibility to R. equi pneumonia were observed for the -57C/T variant in foals from these farms. Although the functional impact of this novel variant remains to be determined, this study represents an important step in our understanding of natural resistance to R. equi foal pneumonia and other intracellular bacterial diseases affecting equids.

The proportion of circulating gammadelta T cells increases after the first week of onset of tularaemia and remains elevated for more than a year.

In various human intracellular bacterial diseases, an increase of the proportion of circulating Vgamma9Vdelta2 T cells has been observed. The prevalence of the finding among infected subjects and the time course of the elevation remain to be investigated. In the present study, comprising blood samples from a large number of cases of ulceroglandular tularaemia, the percentage of Vgamma9Vdelta2 T cells within the first week of onset of disease (5.3 +/- 0.7% (mean +/- s.e.m.)) did not differ from that of control subjects (5.3 +/- 0. 8%). Thereafter, percentages increased rapidly and within the interval of 8-40 days mean levels were > 20% (P < 0.001). Of 45 individuals sampled within 3 months of onset, 42 showed a percentage of Vgamma9Vdelta2 T cells of > 10%. Significantly increased levels were still recorded at 18 months (13.8 +/- 2.4%; P < 0.05) but not at 24 months (10.2 +/- 2.1%; P > 0.10). Thus, a consistent increase of circulating Vgamma9Vdelta2 T cells was demonstrated in tularaemia. The initial delay and the prolonged course of elevation may suggest a role in immunoregulation and/or immunological memory. Furthermore, the percentage of gammadelta T cells expressing tumour necrosis factor-alpha in response to phorbol myristate acetate was decreased during the first week and up to 40 days after onset, possibly reflecting the modulation of an inflammatory response.

V gamma 9V delta 2 T cells in human legionellosis.

In humans, expansion of circulating Vgamma9Vdelta2 T cells seems to be a pathophysiological denominator shared by protozoan and intracellular bacterial diseases. The assumption was tested here on legionellosis, a condition conforming to the category but not yet described with respect to gammadelta T cells. Levels of Vgamma9Vdelta2 T cells in peripheral blood were measured at various intervals in 14 subjects undergoing a Pontiac fever-like disease, shown by serological investigation to be caused by Legionella micdadei. In samples obtained 4 to 6 days after the onset of the disease, the mean percentage (+/- the standard deviation) of Vgamma9Vdelta2+ T cells among CD3+ cells was 1.0% +/- 0.5%, compared to 5.0% +/- 3.9% in healthy control subjects (P < 0.001). Thereafter, a pronounced increase occurred and at 2 to 7 weeks after onset, mean peak levels were as high as approximately equal to 15%. During the next 6 months, values slowly declined, although without reaching the normal range. Percentages of gammadelta+ T cells expressing tumor necrosis factor alpha or gamma interferon in response to phorbol myristate acetate were assayed in vitro. At 14 to 16 days after the onset of disease, the expression of both cytokines was increased (P < 0.01), whereas at 5 to 7 weeks, the expression of tumor necrosis factor alpha was decreased (P < 0.05), possibly reflecting modulation of an inflammatory response. In conclusion, Pontiac fever was found to be associated with a pronounced and long-lasting expansion of Vgamma9Vdelta2 T cells, implying that the subset may also be pathophysiologically important in a mild and transient form of intracellular bacterial diseases. Surprisingly, the expansion was preceded by a depletion of circulatory Vgamma9Vdelta2 T cells. Possibly, Vgamma9Vdelta2 T cells are initially recruited to a site of infection before they expand in response to antigen and occur in high numbers in blood.