Combined immunotherapeutic effect of Leishmania-derived recombinant aldolase and Ambisome against experimental visceral leishmaniasis.

BACKGROUND: Available therapeutics for visceral leishmaniasis (VL), a deadly parasitic infection, are usually associated with inadequate efficacy and adverse aftereffects. Further, the primary site of Leishmania parasite are host macrophages resulting in compromised immunity; ensuing marked T-cell immunosuppression. Such settings emphasize the exploration of chemo-immunotherapeutic strategies for improvising the infected person's immune status with better resolution of infection. METHODS: Present work employs the immunization of Leishmania-infected hamsters with Leishmania-derived recombinant aldolase (rLdAld) and enolase (rLdEno) proteins in consort with the sub-optimal dose of Ambisome (2.5 mg/kg). After the completion of immunization, hamsters were sacrificed on day 60 and 90 post infection and different organ samples were collected to perform immunological assay for evaluating the therapeutic efficacy and modulation in protective cellular immune responses. RESULTS: Combining these proteins, particularly rLdAld with Ambisome (2.5 mg/kg), has significantly reduced the parasitic load (∼80%) with remarkable enhancement in DTH and lymphoproliferative responses compared to the infected control and only Ambisome treated groups. Moreover, cytokine levels at RNA and protein levels were noticed to be inclined towards Th-1 phenotype through up-regulation of IFN-γ and TNF-α with significant down-regulation in IL-10 and TGF-ß expression, an indication towards the generation of protective immunity against experimental VL. CONCLUSION: Our experimental findings demonstrated that the chemo-immunotherapeutic approach could be an effective way of controlling human VL infection at minimal dosages of antileishmanial with reduced side-effects and propensity of drug resistance emergence.

Gut Microbiota Interventions for the Management of Obesity: A Literature Review.

The gut microbiota (GM) has been recognized as an important factor in the development of metabolic diseases such as obesity; it has been reported that the composition of the GM differs in obese and lean subjects, suggesting that microbiota dysbiosis can contribute to changes in body weight. Dysbiosis occurs due to an imbalance in the composition of gut bacteria, changes in the metabolic process, or changes in the distribution of microbiota within the gut. Dysbiosis can change the functioning of the intestinal barrier and the gut-associated lymphoid tissues (GALT). Microbial manipulation may help with preventing or treating weight gain and associated comorbidities. Approaches to this may range from dietary manipulation, which is suitable to treat the individual's microflora, to probiotics, prebiotics, synbiotics, and fecal microbiota transplant (FMT).

Compliance with the smoke-free public places legislation in Nepal: A cross-sectional study from Biratnagar Metropolitan City.

BACKGROUND: Smoke-free legislation banning tobacco smoking in public places was implemented across Nepal in 2014 with the ambition to reduce the impact of second-hand smoking. As part of a comprehensive policy package on tobacco control, the implementation of the legislation has seen a marked reduction in tobacco consumption. Yet there remains uncertainty about the level of compliance with smoke-free public places. OBJECTIVES: This study assesses the compliance with smoke-free laws in public places and the factors associated with active smoking in public places in Biratnagar Metropolitan City, Nepal. METHODS: A cross-sectional study was conducted in the Biratnagar metropolitan city in Province 1 of Nepal from July to December 2019. A total of 725 public places within the metropolitan city were surveyed using a structured survey tool. Active smoking was the primary outcome of the study which was defined as smoking by any person during the data collection time at the designated public place. RESULTS: The overall compliance with smoke-free legislation was 56.4%. The highest compliance (75.0%) was observed in Government office buildings. The lowest compliance was observed in eateries, entertainment, and shopping venues (26.3%). There was a statistically significant association between active smoking and the presence of 'no smoking' notices appended at the entrance and the odds of active smoking in eateries, entertainment, hospitality, shopping venues, transportations and transits was higher compared to education and health care institutions. None of the 'no smoking' notices displayed fully adhered to the contents as prescribed by the law. CONCLUSION: As more than half of the public places complied with the requirements of the legislation, there was satisfactory overall compliance with the smoke-free public places law in this study. The public venues (eateries, shopping venues and transportations) that are more frequently visited and have a high turnover of the public have lower compliance with the legislation. The content of the message in the 'no smoking' notices needs close attention to adhere to the legal requirements.

A Chimera of Th1 Stimulatory Proteins of Leishmania donovani Offers Moderate Immunotherapeutic Efficacy with a Th1-Inclined Immune Response against Visceral Leishmaniasis.

Immunotherapy, a treatment based on host immune system activation, has been shown to provide a substitute for marginally effective conventional chemotherapy in controlling visceral leishmaniasis (VL), the deadliest form of leishmaniasis. As the majority of endemic inhabitants exhibit either subclinical or asymptomatic infection which often develops into the active disease state, therapeutic intervention seems to be an important avenue for combating infections by stimulating the natural defense system of infected individuals. With this perspective, the present study focuses on two immunodominant Leishmania (L.) donovani antigens (triosephosphate isomerase and enolase) previously proved to be potent prophylactic VL vaccine candidates, for generating a recombinant chimeric antigen. This is based on the premise that in a heterogeneous population, a multivalent antigen vaccine would be required for an effective response against leishmaniasis (a complex parasitic disease). The resulting molecule rLdT-E chimeric protein was evaluated for its immunogenicity and immunotherapeutic efficacy. A Th1 stimulating adjuvant BCG was employed with the protein which showed a remarkable 70% inhibition of splenic parasitic multiplication positively correlated with boosted Th1 dominant immune response against lethal L. donovani challenge in hamsters as evidenced by high IFN-γ and TNF-α and low IL-10. In addition, immunological analysis of antibody subclass presented IgG2-based humoral response besides considerable delayed-type hypersensitivity and lymphocyte proliferative responses in rLdT-E/BCG-treated animals. Our observations indicate the potential of the chimera towards its candidature for an effective vaccine against Leishmania donovani infection.

Erdheim Chester disease: a subtle quiddity; the first case reported from Nepal.

Erdheim-Chester disease (ECD) is a rare entity throughout the world. This is the first case reported in Nepal. ECD is a rare aggressive, non-Langerhan's histocytosis of unknown origin with classical histological features. The patient usually presents with bone pain or skeletal symptoms along with other constitutional syndrome. Although, no definitive therapy has been approved, interferon-alfa (or Pegylated Interferon-alfa) is considered as initial therapy. In this case report, we found a patient with right-sided localized chest pain for which he was evaluated with bone scan and excisional bone biopsy and its findings support the diagnosis of ECD.

Prophylactic interferon-γ and interleukin-17 facilitate parasite clearance in experimental visceral leishmaniasis.

BACKGROUND AND OBJECTIVE: The synergy of interleukin (IL)-17 along with other pro-inflammatory cytokines is well known in various autoimmune and infectious diseases. A longitudinal study in the Sudanese population showed an association of IL-17 with the protection of kala-azar outbreak. The protective role of IL-17 is also known in terms of expansion of IL-17-producing cells in vaccine-induced immunity. However, the prophylactic role of IL-17 in visceral leishmaniasis has still not been validated. In the present study, we evaluated the prophylactic efficacy of IL-17A and interferon (IFN)-γ in Leishmania donovani-challenged Balb/c mice. MATERIALS AND METHODS: Two doses of recombinant IL (rIL)-17A and/or IFN-γ were administered intraperitoneally after/at 1 week interval and then the mice were challenged with amastigote form of L. donovani. At 45 days of postchallenge, mice were sacrificed and evaluated for change in the body and organ weight, parasitic load in visceral organs, and fold change in gene expression of cytokines. RESULTS: We observed that the prophylactic use of rIL-17A and IFN-γ alone or in combination significantly inhibited the parasitic load in visceral organs. Furthermore, pro-inflammatory cytokine gene expression increased up to 2-4-folds in mice treated with recombinant cytokines. CONCLUSION: Our results suggest that prophylactic use of recombinant IFN-γ and IL-17A inhibits parasitic growth in visceral organs of L. donovani-challenged experimental mice model, especially through upregulation of pro-inflammatory cytokines' gene expression.

Immunogenicity and Protective Efficacy of T-Cell Epitopes Derived From Potential Th1 Stimulatory Proteins of Leishmania (Leishmania) donovani.

Development of a suitable vaccine against visceral leishmaniasis (VL), a fatal parasitic disease, is considered to be vital for maintaining the success of kala-azar control programs. The fact that Leishmania-infected individuals generate life-long immunity offers a viable proposition in this direction. Our prior studies demonstrated that T-helper1 (Th1) type of cellular response was generated by six potential recombinant proteins viz. elongation factor-2 (elF-2), enolase, aldolase, triose phosphate isomerase (TPI), protein disulfide isomerase (PDI) and p45, derived from a soluble antigenic fraction (89.9-97.1 kDa) of Leishmania (Leishmania) donovani promastigote, in treated Leishmania patients and golden hamsters and showed significant prophylactic potential against experimental VL. Moreover, since, it is well-known that our immune system, in general, triggers production of specific protective immunity in response to a small number of amino acids (peptide), this led to the identification of antigenic epitopes of the above-stated proteins utilizing immunoinformatics. Out of thirty-six, three peptides-P-10 (enolase), P-14, and P-15 (TPI) elicited common significant lymphoproliferative as well as Th1-biased cytokine responses both in golden hamsters and human subjects. Further, immunization with these peptides plus BCG offered 75% prophylactic efficacy with boosted cellular immune response in golden hamsters against Leishmania challenge which is indicative of their candidature as potential vaccine candidates.

Over-Expression of Cysteine Leucine Rich Protein Is Related to SAG Resistance in Clinical Isolates of Leishmania donovani.

BACKGROUND: Resistance emergence against antileishmanial drugs, particularly Sodium Antimony Gluconate (SAG) has severely hampered the therapeutic strategy against visceral leishmaniasis, the mechanism of resistance being indistinguishable. Cysteine leucine rich protein (CLrP), was recognized as one of the overexpressed proteins in resistant isolates, as observed in differential proteomics between sensitive and resistant isolates of L. donovani. The present study deals with the characterization of CLrP and for its possible connection with SAG resistance. METHODOLOGY AND PRINCIPAL FINDINGS: In pursuance of deciphering the role of CLrP in SAG resistance, gene was cloned, over-expressed in E. coli system and thereafter antibody was raised. The expression profile of CLrP and was found to be over-expressed in SAG resistant clinical isolates of L. donovani as compared to SAG sensitive ones when investigated by real-time PCR and western blotting. CLrP has been characterized through bioinformatics, immunoblotting and immunolocalization analysis, which reveals its post-translational modification along with its dual existence in the nucleus as well as in the membrane of the parasite. Further investigation using a ChIP assay confirmed its DNA binding potential. Over-expression of CLrP in sensitive isolate of L. donovani significantly decreased its responsiveness to SAG (SbV and SbIII) and a shift towards the resistant mode was observed. Further, a significant increase in its infectivity in murine macrophages has been observed. CONCLUSION/SIGNIFICANCE: The study reports the differential expression of CLrP in SAG sensitive and resistant isolates of L. donovani. Functional intricacy of CLrP increases with dual localization, glycosylation and DNA binding potential of the protein. Further over-expressing CLrP in sensitive isolate of L. donovani shows significantly decreased sensitivity towards SAG and increased infectivity as well, thus assisting the parasite in securing a safe niche. Results indicates the possible contribution of CLrP to antimonial resistance in L. donovani by assisting the parasite growth in the macrophages.

Visceral Leishmaniasis: Advancements in Vaccine Development via Classical and Molecular Approaches.

Visceral leishmaniasis (VL) or kala-azar, a vector-borne protozoan disease, shows endemicity in larger areas of the tropical, subtropical and the Mediterranean countries. WHO report suggested that an annual incidence of VL is nearly 200,000 to 400,000 cases, resulting in 20,000 to 30,000 deaths per year. Treatment with available anti-leishmanial drugs are not cost effective, with varied efficacies and higher relapse rate, which poses a major challenge to current kala-azar control program in Indian subcontinent. Therefore, a vaccine against VL is imperative and knowing the fact that recovered individuals developed lifelong immunity against re-infection, it is feasible. Vaccine development program, though time taking, has recently gained momentum with the emergence of omic era, i.e., from genomics to immunomics. Classical as well as molecular methodologies have been overtaken with alternative strategies wherein proteomics based knowledge combined with computational techniques (immunoinformatics) speed up the identification and detailed characterization of new antigens for potential vaccine candidates. This may eventually help in the designing of polyvalent synthetic and recombinant chimeric vaccines as an effective intervention measures to control the disease in endemic areas. This review focuses on such newer approaches being utilized for vaccine development against VL.