Seroepidemiology of Spotted Fever Rickettsiosis in Uttar Pradesh: A Prospective Study.

INTRODUCTION: Spotted Fever Rickettsiosis (SFR), an acute febrile illness caused by Rickettsia rickettsii, R. conorii and R. akari which is associated with considerable morbidity and mortality. SFR is one of the most covert emerging infections of the present time which is prevalent in various parts of India as shown by the increase in the number of clinically diagnosed patients in various states except Uttar Pradesh. AIM: To diagnose SFR in clinically suspected patients using serological tests and recognition of common epidemiologic situations and clinical manifestations of SFR in the state of Uttar Pradesh. MATERIALS AND METHODS: Patients of all age groups presented with a diagnosis of Pyrexia of Unknown Origin (PUO) from May 2013 to February 2015 were evaluated. Testing was done using a nonspecific Weil felix test followed by more specific Enzyme Linked Immunosorbent Assay (ELISA) and a gold standard Immunofluorescence Assay (IFA) test for specific IgM antibodies against Rickettsia conorii. The data was statistically analysed on Graph Pad Prism (5.0) software by using Chi-square test. RESULTS: Of the 432 patient samples tested by non specific Weil felix test, 200 (46.29 %) samples showed titre 1:80 or more and were taken as positive. Similarly out of the 432 blood samples tested by both ELISA and IFA based test against Rickettsiaconorii IgM antibody, only 115 (26.62%) samples were found to be positive and these samples were also positive by Weil felix. The common symptoms noted were fever, hepatomegaly, thrombocytopenia, lymphadenopathy and rashes, nausea followed by icterus, cyanosis, headache, oedema and abdominal pain. Eschar was found in only four (3.4%) patients. We also found that 31 patients with SFR also had associated co-infections like typhoid, malaria, dengue and hepatitis. CONCLUSION: Our findings demonstrated that Weil Felix test can fill in as an underlying yet not sole strategy to perceive and analyse rickettsial ailments, as it needs specificity. So, it may be used to assess the burden in the area and later on other tests like ELISA or IFA can be added, as these are more specific diagnostic tests. Further, our results also showed that if a patient tests positive for the more common endemic infections, we must test for rickettsiosis so that appropriate treatment could be administered.

Withania somnifera chemotype NMITLI 101R significantly increases the efficacy of antileishmanial drugs by generating strong IFN-γ and IL-12 mediated immune responses in Leishmania donovani infected hamsters.

BACKGROUND: Withania somnifera (L.) Dunal (Solanaceae), commonly known as Ashwagandha, is one of the most important medicinal plant in the traditional Indian medical systems. Pharmacological studies have established that root extracts of W. somnifera contain several bioactive constituents called withanolides. The plant has long been used for its several beneficial properties and recently as an immunomodulator. HYPOTHESIS/PURPOSE: A combination therapy including a potential and safe immunostimulant with lower doses of effective drug, which can reduce the parasitic burden and simultaneously can produce an enhancement of adaptive immunity, has proven to be significantly a more effective approach than immunotherapy or drug therapy alone. STUDY DESIGN: Evaluation of the immunostimulatory effect of W. somnifera chemotype NMITLI 101R when used in combination with ED50 doses of antileishmanial drugs in Leishmania donovani infected hamsters. METHODS: Infected animals were administered with chemotype 101R(30mg/kg × 15 days) either alone or in combination with ED50 doses of miltefosine (10mg/kg × 5 days), paromomycin (30mg/kg × 5 days) or amphotericin B (0.5mg/kg × 5 days). The treated animals were euthanized on days 30 and 60 post-treatment (p.t.) and checked for parasite clearance, delayed type hypersensitivity (DTH) response, cytokine and inducible nitric oxide synthase levels by real-time PCR, nitric oxide (NO) production, reactive oxygen species (ROS) generation, lymphoproliferative and antibody responses. RESULTS: The group of animals that received 101R and ED50 dose of miltefosine showed optimum inhibition of parasite multiplication (∼98%) by day 60 p.t. followed by the group that received 101R plus paromomycin (∼94%) and 101R plus amphotericin B (∼93%). The efficacy was well supported by the increased inducible NO synthase mRNA transcript, strong IFN-γand IL-12 mediated Th1 immune responses and significantly suppressed levels of Th2 cytokines (IL-4, IL-10 and TGF-ß). Additionally, same therapy also induced significant increase in the level of NO production, ROS generation, Leishmania specific IgG2 antibody along with profound DTH and strong T-cell responses as compared with all the other treated groups. CONCLUSION: Our results suggest that combination of chemotype 101R with ED50 doses of antileishmanial drugs may provide a promising alternative for the cure of visceral leishmaniasis with significant restoration of the host immune response.

Efficacy of Leishmania donovani trypanothione reductase, identified as a potent Th1 stimulatory protein, for its immunogenicity and prophylactic potential against experimental visceral leishmaniasis.

In visceral leishmaniasis (VL), Th1-type of immune responses play an important role which correlates with recovery from and resistance to disease resulting in lifelong immunity. Based on this rationale, the soluble leishmanial antigens that elicit cellular responses in peripheral blood mononuclear cells (PBMCs) from cured Leishmania patients were characterized through immunoproteomic approach which led to the identification of trypanothione reductase (TPR) (a cytosolic enzyme explored as a drug target), as one of the potent Th1 stimulatory protein. In this study, the immunogenicity of recombinant Leishmania donovani TPR (rLdTPR) was assessed in PBMCs of cured Leishmania-infected patients/hamsters and further evaluated its prophylactic efficacy against L. donovani challenges in hamsters. Substantial proliferative responses to rLdTPR, as compared to soluble L. donovani antigen, were observed in Leishmania-infected cured patients as well as in hamsters. Moreover, rLdTPR reasonably stimulated PBMCs of cured Leishmania patients to produce IFNγ, IL-12, and TNF-α but not IL-4 or IL-10. On the other hand, the protein downregulated LPS-induced IL-10 as well as soluble L. donovani antigen-induced IL-4 production in PBMCs of Leishmania patients. In case of cured hamsters, rLdTPR generates mixed Th1 and Th2 immune response. Vaccination with rLdTPR along with Bacillus Calmette-Guerin (BCG) was able to provide considerably good prophylactic efficacy (~60%) against L. donovani challenge in hamsters. The efficacy was supported by the increased inducible NO synthase mRNA transcript and Th1-type cytokines IFNγ, IL-12, and TNF-α and downregulation of IL-4, IL-10, and TGF-ß. Since rLdTPR protein is an important target, further attempts towards determination of immunodominant regions for designing fusion peptides may be taken up to optimize its prophylactic efficacy.

Leishmania donovani triose phosphate isomerase: a potential vaccine target against visceral leishmaniasis.

Visceral leishmaniasis (VL) is one of the most important parasitic diseases with approximately 350 million people at risk. Due to the non availability of an ideal drug, development of a safe, effective, and affordable vaccine could be a solution for control and prevention of this disease. In this study, a potential Th1 stimulatory protein- Triose phosphate isomerase (TPI), a glycolytic enzyme, identified through proteomics from a fraction of Leishmania donovani soluble antigen ranging from 89.9-97.1 kDa, was assessed for its potential as a suitable vaccine candidate. The protein- L. donovani TPI (LdTPI) was cloned, expressed and purified which exhibited the homology of 99% with L. infantum TPI. The rLdTPI was further evaluated for its immunogenicity by lymphoproliferative response (LTT), nitric oxide (NO) production and estimation of cytokines in cured Leishmania patients/hamster. It elicited strong LTT response in cured patients as well as NO production in cured hamsters and stimulated remarkable Th1-type cellular responses including IFN-ã and IL-12 with extremely lower level of IL-10 in Leishmania-infected cured/exposed patients PBMCs in vitro. Vaccination with LdTPI-DNA construct protected naive golden hamsters from virulent L. donovani challenge unambiguously (∼90%). The vaccinated hamsters demonstrated a surge in IFN-ã, TNF-á and IL-12 levels but extreme down-regulation of IL-10 and IL-4 along with profound delayed type hypersensitivity and increased levels of Leishmania-specific IgG2 antibody. Thus, the results are suggestive of the protein having the potential of a strong candidate vaccine.

A novel recombinant Leishmania donovani p45, a partial coding region of methionine aminopeptidase, generates protective immunity by inducing a Th1 stimulatory response against experimental visceral leishmaniasis.

The development of a vaccine against visceral leishmaniasis (VL) conferring long-lasting immunity remains a challenge. Identification and proteomic characterization of parasite proteins led to the detection of p45, a member of the methionine aminopeptidase family. To our knowledge the present study is the first known report that describes the molecular and immunological characterization of p45. Recombinant Leishmania donovani p45 (rLdp45) induced cellular responses in cured hamsters and generated Th1-type cytokines from peripheral blood mononuclear cells of cured/endemic VL patients. Immunization with rLdp45 exerted considerable prophylactic efficacy (∼85%) supported by an increase in mRNA expression of iNOS, IFN-γ, TNF-α and IL-12 and decrease in TGF-ß and IL-4, indicating its potential as a vaccine candidate against VL.

Evaluation of Leishmania donovani protein disulfide isomerase as a potential immunogenic protein/vaccine candidate against visceral Leishmaniasis.

In Leishmania species, Protein disulfide isomerase (PDI)--a redox chaperone, is reported to be involved in its virulence and survival. This protein has also been identified, through proteomics, as a Th1 stimulatory protein in the soluble lysate of a clinical isolate of Leishmania donovani (LdPDI). In the present study, the molecular characterization of LdPDI was carried out and the immunogenicity of recombinant LdPDI (rLdPDI) was assessed by lymphocyte proliferation assay (LTT), nitric oxide (NO) production, estimation of Th1 cytokines (IFN-γ and IL-12) as well as IL-10 in PBMCs of cured/endemic/infected Leishmania patients and cured L. donovani infected hamsters. A significantly higher proliferative response against rLdPDI as well as elevated levels of IFN-γ and IL-12 were observed. The level of IL-10 was found to be highly down regulated in response to rLdPDI. A significant increase in the level of NO production in stimulated hamster macrophages as well as IgG2 antibody and a low level of IgG1 in cured patient's serum was observed. Higher level of IgG2 antibody indicated its Th1 stimulatory potential. The efficacy of pcDNA-LdPDI construct was further evaluated for its prophylactic potential. Vaccination with this construct conferred remarkably good prophylactic efficacy (∼90%) and generated a robust cellular immune response with significant increases in the levels of iNOS transcript as well as TNF-α, IFN-γ and IL-12 cytokines. This was further supported by the high level of IgG2 antibody in vaccinated animals. The in vitro as well as in vivo results thus indicate that LdPDI may be exploited as a potential vaccine candidate against visceral Leishmaniasis (VL).