by
Kaustuv Nayak;
Lichen Jing;
Ronnie M. Russell;
D. Huw Davies;
Gary Hermanson;
Douglas M. Molina;
Xiaowu Liang;
David R. Sherman;
William W. Kwok;
Junbao Yang;
John Kenneth;
Syed F. Ahamed;
Anmol Chandele;
Murali Kaja;
David M. Koelle
Elicitation of CD4 IFN-gamma T cell responses to Mycobacterium tuberculosis (MTB) is a rational vaccine strategy to prevent clinical tuberculosis. Diagnosis of MTB infection is based on T-cell immune memory to MTB antigens. The MTB proteome contains over four thousand open reading frames (ORFs). We conducted a pilot antigen identification study using 164 MTB proteins and MTB-specific T-cells expanded in vitro from 12 persons with latent MTB infection. Enrichment of MTB-reactive T-cells from PBMC used cell sorting or an alternate system compatible with limited resources. MTB proteins were used as single antigens or combinatorial matrices in proliferation and cytokine secretion readouts. Overall, our study found that 44 MTB proteins were antigenic, including 27 not previously characterized as CD4 T-cell antigens. Antigen truncation, peptide, NTM homology, and HLA class II tetramer studies confirmed malate synthase G (encoded by gene Rv1837) as a CD4 T-cell antigen. This simple, scalable system has potential utility for the identification of candidate MTB vaccine and biomarker antigens.
by
Julie A. Womack;
Terrence E. Murphy;
Harini Bathulapalli;
Kathleen M. Akgun;
Cynthia Gibert;
Ken M. Kunisaki;
David Rimland;
Maria Rodriguez-Barradas;
H. Klar Yaggi;
Amy C. Justice;
Nancy S. Redeker
The anaerobic gastrointestinal pathogen Clostridium difficile must form a metabolically dormant spore to survive in oxygenic environments and be transmitted from host to host. The regulatory factors by which C. difficile initiates and controls the early stages of sporulation in C. difficile are not highly conserved in other Clostridium or Bacillus species. Here, we investigated the role of two conserved oligopeptide permeases, Opp and App, in the regulation of sporulation in C. difficile. These permeases are known to positively affect sporulation in Bacillus species through the import of sporulation-specific quorum-sensing peptides. In contrast to other spore-forming bacteria, we discovered that inactivating these permeases in C. difficile resulted in the earlier expression of early sporulation genes and increased sporulation in vitro. Furthermore, disruption of opp and app resulted in greater virulence and increased the amounts of spores recovered from feces in the hamster model of C. difficile infection. Our data suggest that Opp and App indirectly inhibit sporulation, likely through the activities of the transcriptional regulator SinR and its inhibitor, SinI. Taken together, these results indicate that the Opp and App transporters serve a different function in controlling sporulation and virulence in C. difficile than in Bacillus subtilis and suggest that nutrient availability plays a significant role in pathogenesis and sporulation in vivo. This study suggests a link between the nutritional status of the environment and sporulation initiation in C. difficile.
by
Lori N. Eidson;
George T. Kannarkat;
Christopher J. Barnum;
Jianjun Chang;
Jaegwon Chung;
Chelsea Caspell-Garcia;
Peggy Taylor;
Brit Mollenhauer;
Michael G. Schlossmacher;
Larry Ereshefsky;
Mark Yen;
Catherine Kopil;
Mark Frasier;
Kenneth Marek;
Vicki Hertzberg;
MariadeLourdes Tansey
Background: Efforts to identify fluid biomarkers of Parkinson's disease (PD) have intensified in the last decade. As the role of inflammation in PD pathophysiology becomes increasingly recognized, investigators aim to define inflammatory signatures to help elucidate underlying mechanisms of disease pathogenesis and aid in identification of patients with inflammatory endophenotypes that could benefit from immunomodulatory interventions. However, discordant results in the literature and a lack of information regarding the stability of inflammatory factors over a 24-h period have hampered progress. Methods: Here, we measured inflammatory proteins in serum and CSF of a small cohort of PD (n=12) and age-matched healthy control (HC) subjects (n=6) at 11 time points across 24h to (1) identify potential diurnal variation, (2) reveal differences in PD vs HC, and (3) to correlate with CSF levels of amyloid β (Aβ) and α-synuclein in an effort to generate data-driven hypotheses regarding candidate biomarkers of PD. Results: Despite significant variability in other factors, a repeated measures two-way analysis of variance by time and disease state for each analyte revealed that serum IFNγ, TNF, and neutrophil gelatinase-associated lipocalin (NGAL) were stable across 24h and different between HC and PD. Regression analysis revealed that C-reactive protein (CRP) was the only factor with a strong linear relationship between CSF and serum. PD and HC subjects showed significantly different relationships between CSF Aβ proteins and α-synuclein and specific inflammatory factors, and CSF IFNγ and serum IL-8 positively correlated with clinical measures of PD. Finally, linear discriminant analysis revealed that serum TNF and CSF α-synuclein discriminated between PD and HC with a minimum of 82% sensitivity and 83% specificity. Conclusions: Our findings identify a panel of inflammatory factors in serum and CSF that can be reliably measured, distinguish between PD and HC, and monitor inflammation as disease progresses or in response to interventional therapies. This panel may aid in generating hypotheses and feasible experimental designs towards identifying biomarkers of neurodegenerative disease by focusing on analytes that remain stable regardless of time of sample collection.
by
Geoffrey Hart;
Munir Akkaya;
Asiya Chida;
Chungwen Wei;
Scott Jenks;
Christopher Tipton;
Chenfeng He;
Ben S. Wendel;
Jeff Skinner;
Gunjan Arora;
Kassoum Kayentao;
Aissata Ongoiba;
Ogobara Doumbo;
Boubacar Traore;
David L. Narum;
Ning Jiang;
Peter D. Crompton;
Ignacio Sanz;
Susan K. Pierce
Plasmodium falciparum malaria is a deadly infectious disease in which Abs play a critical role in naturally acquired immunity. However, the specificity and nature of Abs elicited in response to malaria are only partially understood. Autoreactivity and polyreactivity are common features of Ab responses in several infections and were suggested to contribute to effective pathogen-specific Ab responses. In this article, we report on the regulation of B cells expressing the inherently autoreactive VH4-34 H chain (identified by the 9G4 mAb) and 9G4 + plasma IgG in adults and children living in a P. falciparum malaria-endemic area in West Africa. The frequency of 9G4 + peripheral blood CD19 + B cells was similar in United States adults and African adults and children; however, more 9G4 + B cells appeared in classical and atypical memory B cell compartments in African children and adults compared with United States adults. The levels of 9G4 + IgG increased following acute febrile malaria but did not increase with age as humoral immunity is acquired or correlate with protection from acute disease. This was the case, even though a portion of 9G4 + B cells acquired phenotypes of atypical and classical memory B cells and 9G4 + IgG contained equivalent numbers of somatic hypermutations compared with all other VHs, a characteristic of secondary Ab repertoire diversification in response to Ag stimulation. Determining the origin and function of 9G4 + B cells and 9G4 + IgG in malaria may contribute to a better understanding of the varied roles of autoreactivity in infectious diseases.