Khima Pandey

Immunomodulation in human dendritic cells leads to induction of interferon-gamma production by Leishmania donovani derived KMP-11 antigen via activation of NF-κB in Indian kala-azar patients.

Dendritic cells (DCs) and macrophages (MΦs) are well-known antigen presenting cells with an ability to produce IL-12 which indicates that they have potential of directing acquired immunity toward a Th1-biased response. The aim of this study was to examine the effect of Leishmania specific KMP-11 antigen through comparison of immune responses after presentation by DCs and MΦs to T cells in Indian patients with VL. Patients with DCS and MΦs were directed against a purified Leishmania donovani antigen (KMP-11) and phytohaemagglutinin (PHA). The cytokines (IL-12, IL-10, and TGF-β) producing abilities of the DCs and MΦs against these antigens were determined by flow cytometry. The transcription factor (NF-κB) and T-cell cytokine support (IFN-γ, IL-10), which could be significant in effector immune function, were also determined. Severe hindrance in the immune protection due to Leishmania parasites, as revealed by decreased expression of IL-12 and upregulation of IL-10 and TGF-β expression in the MΦs compared to DCs, occurred in VL patients. The production of IL-12 in response to L. donovani KMP-11 antigen was increased in DCs which was reduced in MΦs of VL patients. In contrast, the presentation of KMP-11 antigen by DCs to T-lymphocytes in VL patients significantly increased the IFN-γ produced by these immune cells, whereas the levels of IL-10 were significantly elevated after presentation of KMP-11antigen by MΦs. The VL patients were observed with severely dysfunctional MΦs in terms of NF-κB activity that could be recovered only after stimulation of DCs with L. donovani KMP-11 antigen. Immunologically the better competitiveness of KMP-11 antigen through a dendritic cell delivery system may be used to revert T-cell anergy, and control strategy can be designed accordingly against kala-azar.

Imidazolium salt-supported Mukaiyama reagent: an efficient condensation reagent for amide bond formation

A novel imidazolium salt-supported Mukaiyama reagent (2-chloropyridinium salt) has been developed and explored as an efficient coupling agent for amide bond formation. The use of an ionic liquid-supported reagent enabled isolation of the amide products by simple extraction with organic solvents in high purity and avoiding column chromatography purification.

Functionalized ionic liquid-assisted chromatography-free synthesis of bis(indolyl)methanes

A chromatography-free synthesis of bis(indolyl)methanes has been developed using sulfonic acid and sulfonyl hydrazine-functionalized ionic liquids as catalyst and scavenger, respectively. The employed excess aldehyde for completion of the reaction was scavenged by sulfonyl hydrazine-functionalized ionic liquid. Purification of products without column chromatography, ease of monitoring and shorter reaction time are the salient features of the developed protocol. The reuse and regeneration of the catalyst and scavenger have been achieved up to 5 and 2 times, respectively, without significant loss of activity.Graphical Abstract

Ionic liquid-supported benzyl azide: an efficient soluble scavenger for alkynes

An ionic liquid functionalized with benzyl azide was synthesized and its synthetic utility was evaluated by scavenging excess alkynes in the synthesis of 2,4-disubstituted quinoline via the Povarov reaction. The ionic liquid-supported benzyl azide gave excellent efficiency in alkyne scavenging (85–100%). Purification of the products without column chromatography, ease of monitoring, high loading of the scavenger and shorter scavenging time are some of the advantages of this approach over solid-supported scavengers.

Design of digital weight transfer display for agricultural tractors

A microcontroller based digital display unit was developed for 2WD agricultural tractors to measure and display the weight transfer from tractor front axle. The device includes a transducer for measuring the tractor front end reaction, an amplifier to amplify the transducer signal and a microcontroller to calculate and display the weight transfer from the front axle. The developed device can be mounted on any make and model of 2WD tractor. The digital display unit was rigorously tested in the laboratory as well as in the field. A maximum of + 3.5% variation in weight transfer was observed between the theoretically calculated and experimentally observed values.