Human immunity to chikungunya infection

Chikungunyna virus is expanding globally and continue to cause major public health threat to Indian populations. Vaccine efforts are underway, and it is hoped that these will eventually progress to human evaluation. However, currently we have little understanding of the phenotypes and functions of the human T cells in chikungunya patients, a knowledge that is essential for improving vaccine design/testing and evaluation efforts. Here, we provide a detailed analysis of the CD8 T cell responses in chikungunya patients from India. We found that CD38+ HLADR+ CD8 T cell subset expanded dramatically in chikungunya febrile patients with frequencies averaging about 20% of the total CD8 T cells, and reaching as high as 50% of the CD8 T cells in some patients. The frequencies of these activated CD8 T cells were substantially low and barely above background levels in afebrile patients reporting to the clinic with persistent arthralgia/arthritis that was lasting for more than 30 days. These massively expanding CD8 T cells observed in the acute febrile patients were highly proliferating (KI67 ), robustly expressing markers indicative strong Th1 differentiation (T-bet), cytotoxic functions (Perforin) and inflammatory/synovial tissue homing characteristics (CX3CR1 and CXCR4). Interestingly, antigen-stimulation mediated IFN-g producing functions of these cells was highly compromized, reminiscent of the “cytokine stunned” phenotype. Taken together, these results suggest that these highly differentiated effector CD8 T cell that were massively expanding during acute chikungunya febrile infection might be involved in protection by homing to infected tissues and eliminating infected targets rather than causing inflammation.

Enhanced plant growth promoting role of phycomolecules coated zinc oxide nanoparticles with P supplementation in cotton (Gossypium hirsutum L.)

This report focuses on application of zinc oxide nanoparticles (ZnONPs) carrying phycomolecule ligands as a novel plant growth promoter aimed at increasing the crop productivity. The present investigation examined the effect of ZnONPs on plant growth characteristics, and associated biochemical changes in cotton (Gossypium hirsutum L.) following growth in a range of concentrations (25-200 mg L^-l ZnONPs) in combination with 100 mM P in a hydroponic system. Treated plants registered an increase in growth and total biomass by 130.6% and 131%, respectively, over control. Results demonstrated a significant increase in the level of chlorophyll a (141.6%), b (134.7%), carotenoids (138.6%), and total soluble protein contents (179.4%); at the same time, a significant reduction (68%) in the level of malondialdehyde (MDA) in leaves with respect to control. Interestingly, a significant increase in superoxide dismutase (SOD, 264.2%), and peroxidase (POX, 182.8%) enzyme activities followed by a decrease in the catalase (CAT) activity, in response to above treatments. These results suggest that bioengineered ZnONPs interact with meristematic cells triggering biochemical pathways conducive to an accumulation of biomass. Further investigations will map out the mode of action involved in growth promotion.

Tandem Prins/Wagner/Ritter process for the stereoselective synthesis of (3-oxabicyclo[4.2.0]octanyl)amide and (1-(5-aryltetrahydrofuran-3-yl)cyclobutyl)amide derivatives

A novel synthesis of 4-aryl-(3-oxabicyclo[4.2.0]octan-1-yl)amide and (1-(5-aryltetrahydrofuran-3-yl)cyclobutyl)amide derivatives was achieved through a sequential Prins/Wagner/Ritter process.

High intratumoural level of cytokines mediates efficient regression of a rat histiocytoma

We have studied the role of cytokines in the spontaneous regression of AK-5 histiocytoma in syngeneic rats. Animals in which the tumour regresses show high levels of cytokines in the serum compared with animals which succumb to the tumour, and levels of IL-2, IL-4, IL-12, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) are significantly higher in tumour tissue of the former. Thus there is an association between rejection of the tumour and the levels of cytokines present in the tumour mass. Our results also suggest a predominant Th1-type of response in those rats that display early tumour rejection.

Differential modulation of LAK and ADCC functions of natural killer cells from AK-5 tumor-bearing rats by IL-2, IL-12 and IFN-gamma

Modulation of NK cell activity by various lymphokines is well documented. Freshly isolated NK cells exhibit natural cytotoxicity (NC) and antibody-dependent cellular cytotoxicity (ADCC) against certain targets. Upon stimulation with IL-2, the NK cells acquire lymphokine-activated killer (LAK) activity, which enables them to kill a wide variety of targets. Our results demonstrate that freshly isolated NK cells from tumor-bearing rats exhibit NK activity towards YAC-1, and ADCC activity towards AK-5 targets. Fresh NK cells did not lyse AK-5 targets in the absence of anti AK-5 antibody. However, in vitro culture of fresh NK cells in the presence of rat recombinant IL-2 (r-IL-2) over a period of 7 days resulted in complete loss of ADCC activity with concomitant acquisition of LAK activity on AK-5 tumor targets. The LAK and ADCC activities could be effectively distinguished based on our observation that monoclonal anti-rat ICAM-1 and anti-rat LFA-1 antibodies inhibited only LAK activity, but not ADCC activity, in addition, anti-AK-5 antiserum, but not purified anti-AK-5 antibody, inhibited LAK activity, suggesting that soluble ICAM-1 present in hyperimmune serum could be responsible for inhibition of LAK activity. The loss of ADCC activity upon culture of NK cells with rIL-2 was not observed when the cultures were grown on a macrophage feeder layer. In addition, NK cells retained their ADCC activity when cultures were supplemented with a combination of recombinant IL-2 and IL-12. However IL-2, IFN-gamma or IL-12 alone did not prevent the loss of ADCC activity, suggesting the requirement of a combination of these lymphokines for the maintainance of ADCC activity.