Mycobacterium avium ssp. paratuberculosis recombinant heat shock protein 70 interaction with different bovine antigen-presenting cells

Application of antibodies to recombinant heat shock protein 70 in immunohistochemical diagnosis of mycobacterium avium subspecies paratuberculosis in tissues of naturally infected cattle

Background

Detection of Mycobacterium avium subspecies paratuberculosis (MAP) infection is key to the control of Johne’s disease. Immunohistochemistry is one of the methods of detection of MAP infection in tissues. However, unavailability of commercial antibodies that can detect the organism is a limiting factor for the use of immunohistochemistry. This study was aimed at developing an immunohistochemistry method to diagnose MAP in infected tissues using antibodies against MAP recombinant heat shock protein 70kd.

Results

MAP Heat shock protein 70 gene was amplified and cloned into an expression vector, Champion pET-SUMO, then expressed in E coli, purified and used to produce polyclonal rabbit antibodies against the Heat shock protein. Immunohistochemistry was performed in 35 MAP infected tissues with anti-HSP70 polyclonal antibodies. All 35 MAP infected tissues were positive for MAP within macrophages, epithelioid cells and giant cells either in clumps or singly as individual bacilli. No positive staining was seen in the three uninfected normal tissues and in MAP infected tissues where primary antibodies were substituted with PBS or pre-immune serum from the same rabbit.

Conclusion

Anti-HSP70 produced in this study offers an opportunity for improved diagnosis, screening of MAP in animal tissues and in studies on the pathogenesis of MAP

Electronic supplementary material

The online version of this article (doi:10.1186/s13620-017-0088-7) contains supplementary material, which is available to authorized users.

Screening of Mycobacterium avium subsp. paratuberculosis mutants for attenuation in a bovine monocyte-derived macrophage model

Vaccination remains a major tool for prevention and progression of Johne's disease, a chronic enteritis of ruminants worldwide. Currently there is only one licensed vaccine within the United States and two vaccines licensed internationally against Johne's disease. All licensed vaccines reduce fecal shedding of Mycobacterium avium subsp. paratuberculosis (MAP) and delay disease progression. However, there are no available vaccines that prevent disease onset. A joint effort by the Johne's Disease Integrated Program (JDIP), a USDA-funded consortium, and USDA—APHIS/VS sought to identify transposon insertion mutant strains as vaccine candidates in part of a three phase study. The focus of the Phase I study was to evaluate MAP mutant attenuation in a well-defined in vitro bovine monocyte-derived macrophage (MDM) model. Attenuation was determined by colony forming unit (CFUs) counts and slope estimates. Based on CFU counts alone, the MDM model did not identify any mutant that significantly differed from the wild-type control, MAP K-10. Slope estimates using mixed models approach identified six mutants as being attenuated. These were enrolled in protection studies involving murine and baby goat vaccination-challenge models. MDM based approach identified trends in attenuation but this did not correlate with protection in a natural host model. These results suggest the need for alternative strategies for Johne's disease vaccine candidate screening and evaluation.

CD91-Dependent Modulation of Immune Responses by Heat Shock Proteins: A Role in Autoimmunity

Heat shock proteins (HSPs) have been known for decades for their ability to protect cells under stressful conditions. In the 1980s a new role was ascribed for several HSPs given their ability to elicit specific immune responses in the setting of cancer and infectious disease. These immune responses have primarily been harnessed for the immunotherapy of cancer in the clinical setting. However, because of the ability of HSPs to prime diverse immune responses, they have also been used for modulation of immune responses during autoimmunity. The apparent dichotomy of immune responses elicited by HSPs is discussed here on a molecular and cellular level. The potential clinical application of HSP-mediated immune responses for therapy of autoimmune diseases is reviewed.

Primary transcriptomes of Mycobacterium avium subsp. paratuberculosis reveal proprietary pathways in tissue and macrophages

Background

Mycobacterium avium subsp. paratuberculosis (MAP) persistently infects intestines and mesenteric lymph nodes leading to a prolonged subclinical disease. The MAP genome sequence was published in 2005, yet its transcriptional organization in natural infection is unknown. While prior research analyzed regulated gene sets utilizing defined, in vitro stress related or advanced surgical methods with various animal species, we investigated the intracellular lifestyle of MAP in the intestines and lymph nodes to understand the MAP pathways that function to govern this persistence.

Results

Our transcriptional analysis shows that 21%, 8% and 3% of the entire MAP genome was represented either inside tissues, macrophages or both, respectively. Transcripts belonging to latency and cell envelope biogenesis were upregulated in the intestinal tissues whereas those belonging to intracellular trafficking and secretion were upregulated inside the macrophages. Transcriptomes of natural infection and in vitro macrophage infection shared genes involved in transcription and inorganic ion transport and metabolism. MAP specific genes within large sequence polymorphisms of ancestral M. avium complex were downregulated exclusively in natural infection.

Conclusions

We have unveiled common and unique MAP pathways associated with persistence, cell wall biogenesis and virulence in naturally infected cow intestines, lymph nodes and in vitro infected macrophages. This dichotomy also suggests that in vitro macrophage models may be insufficient in providing accurate information on the events that transpire during natural infection. This is the first report to examine the primary transcriptome of MAP at the local infection site (i.e. intestinal tissue). Regulatory pathways that govern the lifecycle of MAP appear to be specified by tissue and cell type. While tissues show a "shut-down" of major MAP metabolic genes, infected macrophages upregulate several MAP specific genes along with a putative pathogenicity island responsible for iron acquisition. Many of these regulatory pathways rely on the advanced interplay of host and pathogen and in order to decipher their message, an interactome must be established using a systems biology approach. Identified MAP pathways place current research into direct alignment in meeting the future challenge of creating a MAP-host interactome.

Therapeutic vaccine comprising Mycobacterium HSP70

BACKGROUND

Mycobacterium avium ssp. paratuberculosis is the causative agent of Johen's disease. This infection of the small intestine is a global problem in the livestock industry. Bacterial shedding by infected but subclinical animals, and transmission via the fecal or intrauterine route and through colostrum and/or milk, make containment and eradication of this disease highly problematic. Current vaccine strategies are ineffective and no effective therapy is available.

OBJECTIVE

Within the broader scope of therapeutic uses of recombinant heat-shock protein 70 (HSP70), the present article evaluates the claim of patent WO08040691.

CONCLUSION

The patent under comment here covers the ability of recombinant Mycobacterium avium ssp. paratuberculsis (MAP) HSP70, when administered in conjunction with an adjuvant, to result in a significant reduction in bacterial shedding in cattle infected with MAP. Furthermore, its administration does not mask diagnostic assays, allowing clinical diagnosis to be maintained.

Partial role of TLR4 as a receptor responding to damage-associated molecular pattern

Part of pathogen-associated molecular pattern (PAMP) and damage-associated molecular pattern (DAMP) activate antigen-presenting cells through Toll-like receptors (TLRs) to initiate immune responses. However, controversy remains if TLR4 mediates DAMP signaling due to the confounding effects of potential LPS contamination. To test if TLR4 functions as a true receptor for DAMP, we compared TLR4(pos)- and TLR4(neg)-responders in vitro and in vivo after stimulation with whole necrotic cell (NC) lysates. Using CHO reporter cells transfected with anti-TLR4-siRNAs, TLR4 was found to partially mediate NF-kappaB activation in response to NC lysates. TLR4(neg) DCs exhibited less I-A(b) expression and nitric oxide secretion than TLR4(pos) DCs upon NC stimulation and this defect was well correlated with diminished presentation of H-Y antigen by TLR4(neg) DCs to I-A(b)-restricted CD4(pos) Marilyn T cells in vitro. Similarly, TLR4(neg) DCs showed significantly less expression of I-A(b), CD80, CD86, and CD40 than TLR4(pos) DCs when NC lysates were injected into peritoneal cavity. Finally, delayed type hypersensitivity response to OVA was significantly decreased in TLR4(neg) mice when NCs were used as an adjuvant. Taken together, our data support the idea that part of the endogenous ligands presented by NCs could activate APCs thru TLR4 and contribute to the development of antigen-specific adaptive immunity. Therefore, endogenous DAMP ligands themselves, not contaminated LPS, activate TLR4 signaling leading to activation of professional antigen-presenting cells.

Development and use of a partial Mycobacterium avium subspecies paratuberculosis protein array

As an initial step toward systematically characterizing all antigenic proteins produced by a significant veterinary pathogen, 43 recombinant Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) expression clones were constructed, cataloged, and stored. NC filters were spotted with purified proteins from each clone along with a whole cell lysate of M. paratuberculosis. Spots on the resulting dot array consisted of hypothetical proteins (13), metabolic proteins (3), cell envelope proteins (7), known antigens (4), and unique proteins with no similarity in public sequence databases (16). Dot blot arrays were used to profile antibody responses in a rabbit and mouse exposed to M. paratuberculosis as well as in cattle showing clinical signs of Johne's disease. The M. paratuberculosis heat shock protein DnaK, encoded by ORF MAP3840 and a membrane protein (MAP2121c), were identified as the most strongly immunoreactive in both the mouse and rabbit hosts, respectively. MAP3155c, which encodes a hypothetical protein, was most strongly immunoreactive in sera from Johne's disease cattle. This study has enabled direct comparisons of antibody reactivity for an entire panel of over 40 proteins and has laid the foundation for future high throughput production and arraying of M. paratuberculosis surface proteins for immune profiling experiments in cattle.

Live Mycobacterium avium subsp. paratuberculosis and a killed-bacterium vaccine induce distinct subcutaneous granulomas, with unique cellular and cytokine profiles

Type II (lepromatous) granulomas are characterized by a lack of organization, with large numbers of macrophages heavily burdened with bacilli and disorganized lymphocyte infiltrations. Type II granulomas are a characteristic feature of the enteric lesions that develop during clinical Mycobacterium avium subsp. paratuberculosis infection in the bovine. Considering the poor organization and function of these granulomas, it is our hypothesis that dendritic cell (DC) function within the granuloma is impaired during initial infection. In order to test our hypothesis, we used a subcutaneous M. avium subsp. paratuberculosis infection model to examine early DC function within M. avium subsp. paratuberculosis-induced granulomas. In this model, we first characterized the morphology, cellular composition, and cytokine profiles of subcutaneous granulomas that develop 7 days after subcutaneous inoculation with either vaccine or live M. avium subsp. paratuberculosis. Second, we isolated CD11c(+) cells from within granulomas and measured their maturation status and ability to induce T-cell responses. Our results demonstrate that M. avium subsp. paratuberculosis or vaccine administration resulted in the formation of distinct granulomas with unique cellular and cytokine profiles. These distinct profiles corresponded to significant differences in the phenotypes and functional responses of DCs from within the granulomas. Specifically, the DCs from the M. avium subsp. paratuberculosis-induced granulomas had lower levels of expression of costimulatory and chemokine receptors, suggesting limited maturation. This DC phenotype was associated with weaker induction of T-cell proliferation. Taken together, these findings suggest that M. avium subsp. paratuberculosis infection in vivo influences DC function, which may shape the developing granuloma and initial local protection.

Monocyte-derived dendritic cells from chagasic patients vs healthy donors secrete differential levels of IL-10 and IL-12 when stimulated with a protein fragment of Trypanosoma cruzi heat-shock protein-70

We analyzed the effect of the truncated heat-shock protein 70 from Trypanosoma cruzi on maturation of human dendritic cells (DCs) derived from monocytes of peripheral blood mononuclear cells from healthy donors and chagasic patients. The results show that the T-HSP70 is capable of maturing human DCs inducing an increase in the expression level of the CD83, CD86 and human leukocyte antigen-DR surface markers, as well as in the secretion of interleukin (IL)-12, tumor necrosis factor-alpha (TNF-alpha) and IL-6 cytokines. Results also show the existence of a differential functional activity of matured DCs from chagasic patients vs healthy donors in response to T-HSP70 protein and to HSP-70-derived A72 peptide, as only T-HSP70-matured DCs from chagasic patients have an enhanced secretion of IL-10 and a reduced secretion of IL-12. Moreover, the addition of A72 peptide to immature DCs from chagasic patients induced an increase in the percentage of cells expressing CD83 and CD86 molecules regarding to the expression level observed by cells from healthy donors. These findings suggest that T. cruzi HSP70 protein may induce a specific maturation profile on chagasic patients' DCs, which would favor the persistence of the parasite in the human host.

Limited phenotypic and functional maturation of bovine monocyte-derived dendritic cells following Mycobacterium avium subspecies paratuberculosis infection in vitro

After encountering antigen, dendritic cells (DC) must differentiate into a fully mature phenotype to induce a protective, lasting T cell immunity. Paratuberculosis is a disease caused by the intracellular pathogen Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) and is characterized by a transient cell mediated immune response, that when dissipates correlates to the onset of clinical disease. In order to study the mechanism of early cellular immunity associated with M. paratuberculosis infection, we tested the hypothesis that M. paratuberculosis infected bovine DC have impaired activation and maturation thus are defective in the initiation of a sustainable and protective Th1 immune response locally. Our results demonstrate that M. paratuberculosis infected DC showed decreased endocytosis of ovalbumin, indicating some functional maturation. Co-stimulatory molecules CD40 and CD80 mRNA expression from M. paratuberculosis infected DC was increased over untreated immature DC. M. paratuberculosis infection induced chemokine receptor CCR7 increase in DC, yet CCR5 remained high. MHC II surface expression remained low on M. paratuberculosis infected DC. M. paratuberculosis infection inhibited pro-inflammatory cytokine IL-12 production and promoted IL-10 secretion by bovine DC. Together, our findings showed evidence of phenotypic and functional maturation of DC. However, we did not see the expected antigen presentation via MHC II and cytokine responses as a fully mature DC. This may suggest semi-mature DC phenotype induced by M. paratuberculosis infection.

Mycobacterium tuberculosis heat-shock protein 70 impairs maturation of dendritic cells from bone marrow precursors, induces interleukin-10 production and inhibits T-cell proliferation in vitro

In different inflammatory disease models, heat-shock proteins (hsp) and hsp-derived peptides have been demonstrated to possess anti-inflammatory properties. While some studies have shown that hsp can directly interact with antigen-presenting cells, others report that bacterial hsp can induce specific T cells with regulatory phenotypes. Effective characterization of the immunomodulatory effects of hsp 70, however, has historically been confounded by lipopolysaccharide (LPS) contamination. In this study, we compared the effects of LPS-free Mycobacterial tuberculosis hsp 70 (TBhsp70) and its possible contaminants on dendritic cells (DC). We demonstrate herein that LPS-free TBhsp70 inhibits murine DC maturation in vitro, while LPS-contaminated TBhsp70 induces DC maturation. Mock recombinant preparations have no effect. In contrast to LPS, TBhsp70 does not induce tumour necrosis factor-alpha production by DC, but interleukin-10. In vivo, only LPS-contaminated TBhsp70 induces up-regulation of CD86 in splenic mature DC. Finally, TBhsp70 inhibited phytohaemagglutinin-induced T-cell proliferation. Our results support the hypothesis that TBhsp70 does not have inflammatory potential, but rather has immunosuppressive properties.

Cytokine responses of bovine macrophages to diverse clinical Mycobacterium avium subspecies paratuberculosis strains

Background

Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of Johne's disease (JD) persistently infects and survives within the host macrophages. While it is established that substantial genotypic variation exists among MAP, evidence for the correlates that associate specific MAP genotypes with clinical or sub-clinical disease phenotypes is presently unknown. Thus we studied strain differences in intracellular MAP survival and host responses in a bovine monocyte derived macrophage (MDM) system.

Results

Intracellular survival studies showed that a bovine MAP isolate (B1018) and a human MAP isolate (Hu6) persisted in relatively higher numbers when compared with a sheep MAP isolate (S7565) at 24-hr, 48-hr and 96-hr post infection (PI). MDMs stimulated with B1018 up-regulated IL-10 at the transcript level and down-regulated TNFα at the protein and transcript levels compared with stimulations by the S7565 and Hu6. MDMs infected with Hu6 showed a down regulatory pattern of IL-10 and TNFα compared to stimulations by S7565. Cells stimulated with B1018 and Hu6 had low levels of matrix metalloprotease-3 (MMP3) and high levels of tissue inhibitor of metalloprotease-1 (TIMP1) at 96-hr PI relative to MDMs stimulated by S7565.

Conclusion

Taken together, results suggest that the bovine (B1018) and the human (Hu6) MAP isolates lead to anti-inflammatory and anti-invasive pathways in the macrophage environment whereas the sheep (S7565) MAP isolate induces a pro-inflammatory pathway. Thus the infecting strain genotype may play a role in polarizing the host immune responses and dictate the clinicopathological outcomes in this economically important disease.