Marked Differences in Mucosal Immune Responses Induced in Ileal versus Jejunal Peyer's Patches to Mycobacterium avium subsp. paratuberculosis Secreted Proteins following Targeted Enteric Infection in Young Calves

Modeling Paratuberculosis in Laboratory Animals, Cells, or Tissues: A Focus on Their Applications for Pathogenesis, Diagnosis, Vaccines, and Therapy Studies

Paratuberculosis is a chronic granulomatous enteritis caused by Mycobacterium avium subsp. Paratuberculosis that affects a wide variety of domestic and wild animals. It is considered one of the diseases with the highest economic impact on the ruminant industry. Despite many efforts and intensive research, paratuberculosis control still remains controversial, and the existing diagnostic and immunoprophylactic tools have great limitations. Thus, models play a crucial role in understanding the pathogenesis of infection and disease, and in testing novel vaccine candidates. Ruminant animal models can be restricted by several reasons, related to space requirements, the cost of the animals, and the maintenance of the facilities. Therefore, we review the potential and limitations of the different experimental approaches currently used in paratuberculosis research, focusing on laboratory animals and cell-based models. The aim of this review is to offer a vision of the models that have been used, and what has been achieved or discovered with each one, so that the reader can choose the best model to answer their scientific questions and prove their hypotheses. Also, we bring forward new approaches that we consider worth exploring in the near future.

Alternatives to antibiotics in veterinary medicine: considerations for the management of Johne's disease

Antibiotic resistance has become a major health concern globally, with current predictions expecting deaths related to resistant infections to surpass those of cancer by 2050. Major efforts are being undertaken to develop derivative and novel alternatives to current antibiotic therapies in human medicine. What appears to be lacking however, are similar efforts into researching the application of those alternatives, such as (bacterio)phage therapy, in veterinary contexts. Agriculture is still undoubtedly the most prominent consumer of antibiotics, with up to 70% of annual antibiotic usage attributed to this sector, despite policies to reduce their use in food animals. This not only increases the risk of resistant infections spreading from farm to community but also the risk that animals may acquire species-specific infections that subvert treatment. While these diseases may not directly affect human welfare, they greatly affect the profit margin of industries reliant on livestock due to the cost of treatments and (more frequently) the losses associated with animal death. This means actively combatting animal infection not only benefits animal welfare but also global economies. In particular, targeting recurring or chronic conditions associated with certain livestock has the potential to greatly reduce financial losses. This can be achieved by developing novel diagnostics to quickly identify ill animals alongside the design of novel therapies. To explore this concept further, this review employs Johne's disease, a chronic gastroenteritis condition that affects ruminants, as a case study to exemplify the benefits of rapid diagnostics and effective treatment of chronic disease, with particular regard to the diagnostic and therapeutic potential of phage.

B cell phenotypes and maturation states in cows naturally infected with Mycobacterium avium subsp. Paratuberculosis

Little is known about the role that B cells play in immune responses to infection with the intracellular pathogen, Mycobacterium avium subsp. paratuberculosis (MAP). Traditionally, the role of B cells has been constrained to their function as antibody-producing cells, however, antibodies are not thought to play a protective role in mycobacterial infections. The present study was designed to characterize B cell subpopulations as well as activation/maturation states in cattle with paratuberculosis. Peripheral blood mononuclear cells (PBMCs) were isolated from noninfected control cows (n = 8); as well cattle naturally infected with MAP in the subclinical (n = 8) and clinical (n = 7) stage of infection and stimulated with MAP antigen for 6 days. MAP infection resulted in greater numbers of total B cells for clinical cows compared to control noninfected cows. The major subpopulation in freshly isolated PBMCs in clinical cows was B-1a B cells, but this shifted to a composite of both B-1a and B-2 B cells upon stimulation of PBMCs with either MAP antigen or pokeweed mitogen, with higher numbers of B-2 B cells. Early B cells were observed to predominate the population of B cells in PBMCs, with lesser populations of germinal B cells, memory B cells and plasma cells. These subpopulations were elevated in clinical cows upon stimulation of PBMCs with MAP antigen, except for plasma cells which were lower compared to control noninfected cows. Increased numbers of B cells in clinical cows aligned with higher expression of B cell markers such as MAPK1/3, BTG1, Bcl2, CD79A and SWAP70, depending upon in vitro stimulation with either mitogen or antigen. This would indicate that the B cells were capable of activation but were anti-apoptotic in nature. The shift to B-2 B cells in the periphery of clinical cows seems to be indicative of an expansion of memory B cells, rather than plasma cells. This may be a last attempt by the host to control the rampant inflammatory state associated with advanced clinical disease.

The Development of 3D Bovine Intestinal Organoid Derived Models to Investigate Mycobacterium Avium ssp Paratuberculosis Pathogenesis

Mycobacterium avium subspecies paratuberculosis (MAP) is the etiological agent of Johne's Disease, a chronic enteritis of ruminants prevalent across the world. It is estimated that approximately 50% of UK dairy herds are infected with MAP, but this is likely an underestimate of the true prevalence. Infection can result in reduced milk yield, infertility and premature culling of the animal, leading to significant losses to the farming economy and negatively affecting animal welfare. Understanding the initial interaction between MAP and the host is critical to develop improved diagnostic tools and novel vaccines. Here we describe the characterisation of three different multicellular in vitro models derived from bovine intestinal tissue, and their use for the study of cellular interactions with MAP. In addition to the previously described basal-out 3D bovine enteroids, we have established viable 2D monolayers and 3D apical-out organoids. The apical-out enteroids differ from previously described bovine enteroids as the apical surface is exposed on the exterior surface of the 3D structure, enabling study of host-pathogen interactions at the epithelial surface without the need for microinjection. We have characterised the cell types present in each model system using RT-qPCR to detect predicted cell type-specific gene expression, and confocal microscopy for cell type-specific protein expression. Each model contained the cells present in the original bovine intestinal tissue, confirming they were representative of the bovine gut. Exposure of the three model systems to the K10 reference strain of MAP K10, and a recent Scottish isolate referred to as C49, led to the observation of intracellular bacteria by confocal microscopy. Enumeration of the bacteria by quantification of genome copy number, indicated that K10 was less invasive than C49 at early time points in infection in all model systems. This study shows that bovine enteroid-based models are permissive to infection with MAP and that these models may be useful in investigating early stages of MAP pathogenesis in a physiologically relevant in vitro system, whilst reducing the use of animals in scientific research.

Bos taurus: urn:lsid:zoobank.org:act:4C90C4FA-6296-4972-BE6A-5EF578677D64

Regionally Distinct Immune and Metabolic Transcriptional Responses in the Bovine Small Intestine and Draining Lymph Nodes During a Subclinical Mycobacterium avium subsp. paratuberculosis Infection

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative infectious agent of Johne’s disease (JD), an incurable granulomatous enteritis affecting domestic livestock and other ruminants around the world. Chronic MAP infections usually begin in calves with MAP uptake by Peyer’s patches (PP) located in the jejunum (JE) and ileum (IL). Determining host responses at these intestinal sites can provide a more complete understanding of how MAP manipulates the local microenvironment to support its long-term survival. We selected naturally infected (MAPinf, n=4) and naive (MAPneg, n=3) cows and transcriptionally profiled the JE and IL regions of the small intestine and draining mesenteric lymph nodes (LN). Differentially expressed (DE) genes associated with MAP infection were identified in the IL (585), JE (218), jejunum lymph node (JELN) (205), and ileum lymph node (ILLN) (117). Three DE genes (CD14, LOC616364 and ENSBTAG00000027033) were common to all MAPinf versus MAPneg tissues. Functional enrichment analysis revealed immune/disease related biological processes gene ontology (GO) terms and pathways predominated in IL tissue, indicative of an activated immune response state. Enriched GO terms and pathways in JE revealed a distinct set of host responses from those detected in IL. Regional differences were also identified between the mesenteric LNs draining each intestinal site. More down-regulated genes (52%) and fewer immune/disease pathways (n=5) were found in the ILLN compared to a higher number of up-regulated DE genes (56%) and enriched immune/disease pathways (n=13) in the JELN. Immunohistochemical staining validated myeloid cell transcriptional changes with increased CD172-positive myeloid cells in IL and JE tissues and draining LNs of MAPinf versus MAPneg cows. Several genes, GO terms, and pathways related to metabolism were significantly DE in IL and JE, but to a lesser extent (comparatively fewer enriched metabolic GO terms and pathways) in JELN suggesting distinct regional metabolic changes in IL compared to JE and JELN in response to MAP infection. These unique tissue- and regional-specific differences provides novel insight into the dichotomy in host responses to MAP infection that occur throughout the small intestine and mesenteric LN of chronically MAP infected cows.

Functional Variants Surrounding Endothelin 2 Are Associated With Mycobacterium avium Subspecies paratuberculosis Infection

Bovine paratuberculosis, caused by Mycobacterium avium subspecies paratuberculosis (MAP), continues to impact the dairy industry through increased morbidity, mortality, and lost production. Although genome-wide association analyses (GWAAs) have identified loci associated with susceptibility to MAP, limited progress has been made in identifying mutations that cause disease susceptibility. A 235-kb region on Bos taurus chromosome 3 (BTA3), containing a 70-kb haplotype block surrounding endothelin 2 (EDN2), has previously been associated with the risk of MAP infection. EDN2 is highly expressed in the gut and is involved in intracellular calcium signaling and a wide array of biological processes. The objective of this study was to identify putative causal mutations for disease susceptibility in the region surrounding EDN2 in Holstein and Jersey cattle. Using sequence data from 10 Holstein and 10 Jersey cattle, common variants within the 70-kb region containing EDN2 were identified. A custom SNP genotyping array fine-mapped the region using 221 Holstein and 51 Jersey cattle and identified 17 putative causal variants (P < 0.01) located in the 5′ region of EDN2 and a SNP in the 3′ UTR (P = 0.00009) associated with MAP infection. MicroRNA interference assays, mRNA stability assays, and electrophoretic mobility shift assays were performed to determine if allelic changes at each SNP resulted in differences in EDN2 stability or expression. Two SNPs [rs109651404 (G/A) and rs110287192 (G/T)] located within the promoter region of EDN2 displayed differential binding affinity for transcription factors in binding sequences harboring the alternate SNP alleles. The luciferase reporter assay revealed that the transcriptional activity of the EDN2 promoter was increased (P < 0.05) with the A allele for rs109651404 and the G allele for rs110287192. These results suggest that the variants rs109651404 and rs110287192 are mutations that alter transcription and thus may alter susceptibility to MAP infection in Holstein and Jersey cattle.

A Bovine Enteric Mycobacterium Infection Model to Analyze Parenteral Vaccine-Induced Mucosal Immunity and Accelerate Vaccine Discovery

Mycobacterial diseases of cattle are responsible for considerable production losses worldwide. In addition to their importance in animals, these infections offer a nuanced approach to understanding persistent mycobacterial infection in native host species. Mycobacteriumavium ssp. paratuberculosis (MAP) is an enteric pathogen that establishes a persistent, asymptomatic infection in the small intestine. Difficulty in reproducing infection in surrogate animal models and limited understanding of mucosal immune responses that control enteric infection in the natural host have been major barriers to MAP vaccine development. We previously developed a reproducible challenge model to establish a consistent MAP infection using surgically isolated intestinal segments prepared in neonatal calves. In the current study, we evaluated whether intestinal segments could be used to screen parenteral vaccines that alter mucosal immune responses to MAP infection. Using Silirum^® – a commercial MAP bacterin – we demonstrate that intestinal segments provide a platform for assessing vaccine efficacy within a relatively rapid period of 28 days post-infection. Significant differences between vaccinates and non-vaccinates could be detected using quantitative metrics including bacterial burden in intestinal tissue, MAP shedding into the intestinal lumen, and vaccine-induced mucosal immune responses. Comparing vaccine-induced responses in mucosal leukocytes isolated from the site of enteric infection versus blood leukocytes revealed substantial inconsistences between these immune compartments. Moreover, parenteral vaccination with Silirum did not induce equal levels of protection throughout the small intestine. Significant control of MAP infection was observed in the continuous but not the discrete Peyer’s patches. Analysis of these regional mucosal immune responses revealed novel correlates of immune protection associated with reduced infection that included an increased frequency of CD335⁺ innate lymphoid cells, and increased expression of IL21 and IL27. Thus, intestinal segments provide a novel model to accelerate vaccine screening and discovery by testing vaccines directly in the natural host and provides a unique opportunity to interrogate mucosal immune responses to mycobacterial infections.

Early supplementation of Saccharomyces cerevisiae boulardii CNCM I-1079 in newborn dairy calves increases IgA production in the intestine at 1 week of age

The early development of immunity and microbiota in the gut of newborn calves can have life-long consequences. Gut microbiota and the intestinal barrier interplay after birth, establishing a homeostatic state whereby mucosal cells cohabit with microorganisms to develop a healthy gut. We hypothesized that postnatal codevelopment of gut immunity and microbiota could be influenced by early-life supplementation with live yeast. Starting from birth, calves either received a daily supplementation of Saccharomyces cerevisiae boulardii CNCM I-1079 (SCB, 10 × 10⁹ cfu/d, n = 10) in the morning meal for 7 d or no supplementation (n = 10). Each animal received 2 adequate colostrum replacer meals at 2 and 12 h of life (expected total IgG fed = 300 g) before being fed milk replacer twice a day. Passive transfer of immunity (total protein, IgG, and IgA) through colostrum was evaluated and endogenous production of IgA was investigated by measuring IgA-producing plasma cells, IgA relative gene expression (PIGR and CD79A), and secretory IgA concentration in the gut. The concentration of targeted microbial groups was evaluated with quantitative PCR in the gut digesta collected at d 7 of life. Early SCB supplementation did not impair immunoglobulin absorption and all calves had successful passive transfer of immunity (serum IgG concentration >15 mg/mL at d 1 and d 7 of age). Although the expression of IgA relative gene expression (PIGR and CD79A) was not different, SCB calves had higher secretory IgA concentrations in the ileum (1.98 ± 0.12 mg/g of dry matter; DM) and colon (1.45 ± 0.12 mg/g of DM) digesta compared with control animals (1.18 and 0.59 ± 0.12 mg/g of DM, respectively). In addition, the number of IgA-producing plasma cells were greater in both ileum (2.55 ± 0.40 cells/mm²) and colon (3.03 ± 0.40 cells/mm²) tissues for SCB calves compared with control (respectively 1.00 ± 0.40 and 0.60 ± 0.42 cells/mm²). Endogenous IgA production in the gut of SCB calves was enhanced, which could make them less prone to pathogen intrusion. In addition, SCB calves had higher Lactobacillus and tended to have higher Faecalibacterium prausnitzii in the jejunum compared with control calves, which suggests that SCB supplementation during early-life gut colonization may have a positive effect in newborn calves. Direct SCB supplementation or the cross-talk between SCB and bacteria may be responsible for stimulating IgA production and may play a key role in shaping early colonization in the gut of newborn calves.

Mycobacterium avium Subspecies paratuberculosis Infects and Replicates within Human Monocyte-Derived Dendritic Cells

BACKGROUND

Mycobacterium avium subspecies paratuberculosis (MAP), a member of the mycobacteriaceae family, causes Johne's disease in ruminants, which resembles Crohn's disease (CD) in humans. MAP was proposed to be one of the causes of human CD, but the evidence remains elusive. Macrophages were reported to be the only cell where MAP proliferates in ruminants and humans and is likely the major producer of TNFα-associated inflammation. However, whether human dendritic cells (DCs), another major antigen-presenting cell (APC), have the ability to harbor MAP and disseminate infection, remains unknown.

METHODS

Human monocyte-derived dendritic cells (moDCs) were infected with MAP and phagocytosis and intracellular survival were quantified by immunofluorescence (IF) and colony counts, respectively. MoDC cytokine expression was measured via ELISA and their activation state was measured via flow cytometry.

RESULTS

We showed that MAP can infect and replicate in human moDCs as means to evade the immune system for successful infection, through inhibition of the phago-lysosome fusion via the secretion of protein tyrosine phosphatase PtpA. This mechanism initially led to a state of tolerance in moDCs and then subsequently caused a pro-inflammatory response as infection persisted, characterized by the upregulation of IL-6 and TNFα, and downregulation of IL-10. Moreover, we showed that moDCs have the ability to phagocytose up to 18% of MAP, when exposed at a multiplicity of infection of 1:1.

CONCLUSION

Infection and subsequent proliferation of MAP within moDCs could provide a unique means for the dissemination of MAP to lymphoid tissue, while altering immune responses to facilitate the persistence of infection of host tissues in CD.

Regional Dichotomy in Enteric Mucosal Immune Responses to a Persistent Mycobacterium avium ssp. paratuberculosis Infection

Chronic enteric Mycobacterium avium ssp. paratuberculosis (MAP) infections are endemic in ruminants globally resulting in significant production losses. The mucosal immune responses occurring at the site of infection, specifically in Peyer's patches (PP), are not well-understood. The ruminant small intestine possesses two functionally distinct PPs. Discrete PPs function as mucosal immune induction sites and a single continuous PP, in the terminal small intestine, functions as a primary lymphoid tissue for B cell repertoire diversification. We investigated whether MAP infection of discrete vs. continuous PPs resulted in the induction of significantly different pathogen-specific immune responses and persistence of MAP infection. Surgically isolated intestinal segments in neonatal calves were used to target MAP infection to individual PPs. At 12 months post-infection, MAP persisted in continuous PP (n = 4), but was significantly reduced (p = 0.046) in discrete PP (n = 5). RNA-seq analysis revealed control of MAP infection in discrete PP was associated with extensive transcriptomic changes (1,707 differentially expressed genes) but MAP persistent in continuous PP elicited few host responses (4 differentially expressed genes). Cytokine gene expression in tissue and MAP-specific recall responses by mucosal immune cells isolated from PP, lamina propria and mesenteric lymph node revealed interleukin (IL)22 and IL27 as unique correlates of protection associated with decreased MAP infection in discrete PP. This study provides the first description of mucosal immune responses occurring in bovine discrete jejunal PPs and reveals that a significant reduction in MAP infection is associated with specific cytokine responses. Conversely, MAP infection persists in the continuous ileal PP with minimal perturbation of host immune responses. These data reveal a marked dichotomy in host-MAP interactions within the two functionally distinct PPs of the small intestine and identifies mucosal immune responses associated with the control of a mycobacterial infection in the natural host.

From Beef to Bees: High-Throughput Kinome Analysis to Understand Host Responses of Livestock Species to Infectious Diseases and Industry-Associated Stress

Within human health research, the remarkable utility of kinase inhibitors as therapeutics has motivated efforts to understand biology at the level of global cellular kinase activity (the kinome). In contrast, the diminished potential for using kinase inhibitors in food animals has dampened efforts to translate this research approach to livestock species. This, in our opinion, was a lost opportunity for livestock researchers given the unique potential of kinome analysis to offer insight into complex biology. To remedy this situation, our lab developed user-friendly, cost-effective approaches for kinome analysis that can be readily incorporated into most research programs but with a specific priority to enable the technology to livestock researchers. These contributions include the development of custom software programs for the creation of species-specific kinome arrays as well as comprehensive deconvolution and analysis of kinome array data. Presented in this review are examples of the application of kinome analysis to highlight the utility of the technology to further our understanding of two key complex biological events of priority to the livestock industry: host immune responses to infectious diseases and animal stress responses. These advances and examples of application aim to provide both mechanisms and motivation for researchers, particularly livestock researchers, to incorporate kinome analysis into their research programs.

An update on Mycobacterium avium subspecies paratuberculosis antigens and their role in the diagnosis of Johne's disease

Mycobacterium avium subsp. paratuberculosis (MAP) is responsible for Johne's disease (JD) or paratuberculosis. Diagnosis of MAP infection by measuring host cell-mediated and humoral immune responses has been a major focus in MAP research. For this purpose, several MAP antigens such as secreted protein, cell envelope protein, cell-mediated immune and lipoprotein antigens have been identified and tested to measure their diagnostic utility with varying degree of success. Identifying the optimal antigen or antigen combinations for diagnosis of infected animals is hindered by the complex nature of the disease, prolonged subclinical infection, the differential expression of antigens and scarcity of well characterized MAP-specific epitopes making selection of a single MAP antigen very difficult. Thus, multiplexing of antigens with larger scale and longitudinal studies may lead to development of cost-effective next generation serodiagnostics. This mini review focuses on the role of different MAP antigens in the diagnosis of JD.

Cyclodextrin/chitosan nanoparticles for oral ovalbumin delivery: Preparation, characterization and intestinal mucosal immunity in mice

A novel oral protein delivery system with enhanced intestinal penetration and improved antigen stability based on chitosan (CS) nanoparticles and antigen-cyclodextrin (CD) inclusion complex was prepared by a precipitation/coacervation method. Ovalbumin (OVA) as a model antigen was firstly encapsulated by cyclodextrin, either β-cyclodextrin (β-CD) or carboxymethyl-hydroxypropyl-β-cyclodextrin (CM-HP-β-CD) and formed OVA-CD inclusion complexes, which were then loaded to chitosan nanoparticles to form OVA loaded β-CD/CS or CM-HP-β-CD/CS nanoparticles with uniform particle size (836.3 and 779.2 nm, respectively) and improved OVA loading efficiency (27.6% and 20.4%, respectively). In vitro drug release studies mimicking oral delivery condition of OVA loaded CD/CS nanoparticles showed low initial releases at pH 1.2 for 2 h less than 3.0% and a delayed release which was below to 30% at pH 6.8 for further 72 h. More importantly, after oral administration of OVA loaded β-CD/CS nanoparticles to Balb/c mice, OVA-specific sIgA levels in jejunum of OVA loaded β-CD/CS nanoparticles were 3.6-fold and 1.9-fold higher than that of OVA solution and OVA loaded chitosan nanoparticles, respectively. In vivo evaluation results showed that OVA loaded CD/CS nanoparticles could enhance its efficacy for inducing intestinal mucosal immune response. In conclusion, our data suggested that CD/CS nanoparticles could serve as a promising antigen-delivery system for oral vaccination.

Resilience to infection by Mycobacterium avium subspecies paratuberculosis following direct intestinal inoculation in calves

Mycobacterium avium subspecies paratuberculosis (Map) is the cause of Johne’s disease, a chronic enteritis of cattle. A significant knowledge gap is how persistence of Map within the intestinal tract after infection contributes to progression of disease. To address this, we exposed calves to Map by direct ileocecal Peyer’s patch injection. Our objective was to characterize the persistence of Map in tissues, associated intestinal lesions, fecal Map shedding, and serum antibody responses, through the first 28-weeks post-inoculation (wpi). Previous work using this model showed 100% rate of Map infection in intestine and lymph node by 12 wpi. We hypothesized that direct inoculation of Map into the distal small intestine would induce intestinal Map infection with local persistence and progression towards clinical disease. However, our data show decreased persistence of Map in the distal small intestine and draining lymph nodes. We identified Map in multiple sections of distal ileum and draining lymph node of all calves at 4 and 12 wpi, but then we observed reduced Map in distal ileum at 20 wpi, and by 28 wpi we found that 50% of animals had no detectable Map in intestine or the lymph node. This provides evidence of resilience to Map infection following direct intestinal Map inoculation. Further work examining the immune responses and host–pathogen interactions associated with this infection model are needed to help elicit the mechanisms underlying resilience to Map infection.

MAP1981c, a Putative Nucleic Acid-Binding Protein, Produced by Mycobacterium avium subsp. paratuberculosis, Induces Maturation of Dendritic Cells and Th1-Polarization

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative pathogen of chronic granulomatous enteropathy (Johne's disease) in animals, and has been focused on its association with various autoimmune diseases in humans, including Crohn's disease. The discovery of novel mycobacterial antigens and exploring their role in host immunity can contribute to the advancement of effective defense strategies including vaccines and diagnostic tools. In a preliminary study, we identified cellular extract proteins of MAP that strongly react with the blood of patients with Crohn's disease. In particular, MAP1981c, a putative nucleic acid-binding protein, showed high expression levels and strong reactivity to IgG and IgM in the sera of patients. Here, we investigated the immunological features of MAP1981c and focused on its interaction with dendritic cells (DCs), confirming its immunomodulatory ability. MAP1981c was shown to recognize Toll-like receptor (TLR) 4, and induce DC maturation and activation by increasing the expression of co-stimulatory (CD80 and CD86) and MHC class I/II molecules and the secretion of pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α) in DCs. This DC activation by MAP1981c was mediated by downstream signaling of TLR4 via MyD88- and TRIF-, MAP kinase-, and NF-κB-dependent signaling pathways. In addition, MAP1981c-treated DCs activated naïve T cells and induced the differentiation of CD4⁺ and CD8⁺ T cells to express T-bet, IFN-γ, and/or IL-2, but not GATA-3 and IL-4, thus indicating that MAP1981c contributes to Th1-type immune responses both in vitro and in vivo. Taken together, these results suggest that MAP1981c is a novel immunocompetent antigen that induces DC maturation and a Th1-biased response upon DC activation, suggesting that MAP1981c can be an effective vaccine and diagnostic target.