Owais Mohammad

Antigen entrapped in the escheriosomes leads to the generation of CD4(+) helper and CD8(+) cytotoxic T cell response.

In previous study, we demonstrated the potential of Escherichia coli (E. coli) lipid liposomes (escheriosomes) to undergo membrane-membrane fusion with cytoplasmic membrane of the target cells including professional antigen presenting cells. Our present study demonstrates that antigen encapsulated in escheriosomes could be successfully delivered simultaneously to the cytosolic as well as endosomal processing pathways of antigen presenting cells, leading to the generation of both CD4(+) T-helper and CD8(+) cytotoxic T cell response. In contrast, encapsulation of same antigen in egg phosphatidyl-choline (egg PC) liposomes, just like antigen-incomplete Freunds adjuvant (IFA) complex, has inefficient access to the cytosolic pathway of MHC I-dependent antigen presentation and failed to generate antigen-specific CD8(+) cytotoxic T cell response. However, both egg PC liposomes as well as escheriosomes-encapsulated antigen elicited strong humoral immune response in immunized animals but antibody titre was significantly higher in the group of animals immunized with escheriosomes-encapsulated antigen. These results imply usage of liposome-based adjuvant as potential candidate vaccine capable of eliciting both cell-mediated as well as humoral immune responses. Furthermore, antigen entrapped in escheriosomes stimulates antigen-specific CD4(+) T cell proliferation and also enhances the level of IL-2, IFN-gamma and IL-4 in the immunized animals.

Engineering of a metagenome derived lipase toward thermal tolerance: Effect of asparagine to lysine mutation on the protein surface

A highly thermostable mutant lipase was generated and characterized. Mutant enzyme demonstrated 144 fold enhanced thermostability over the wild type enzyme at 60°C. Interestingly, the overall catalytic efficiency (k(cat/)K(m)) of mutant was also enhanced (~20 folds). Circular dichroism spectroscopy, studied as function of temperature, demonstrated that the mutant lipase retained its secondary structure up to 70-80°C, whereas wild type protein structure was completely distorted above 35°C. Additionally, the intrinsic tryptophan fluorescence (a probe for the tertiary structure) also displayed difference in the conformation of two enzymes during temperature dependent unfolding. Furthermore, mutation N355K resulted in extensive H-bonding (Lys355 HZ1OE2 Glu284) with a distance 2.44 Å. In contrast to this, Wt enzyme has not shown such H-bonding interaction.

Development, characterization and efficacy of niosomal diallyl disulfide in treatment of disseminated murine candidiasis

UNLABELLED In the current study, a novel niosome based formulation of diallyl disulfide (DADS) was evaluated for its potential to treat disseminated candidiasis in mouse model. Among various non-ionic surfactants tested, niosome formulation prepared using Span 80 was found to be most efficient in the entrapment of DADS. The DADS loaded niosomes had size dimensions in the range of 140 ± 30 nm with zeta potential of -30.67 ± 4.5. Liver/kidney function tests as well as histopathologic studies suggested that noisome-based DADS formulations are safe at the dose investigated. When administered to Candida albicans infected animals, the DADS bearing niosomal formulation cleared the fungal burden and increased their survival much efficiently than its free form. FROM THE CLINICAL EDITOR In this study, a novel niosomal formulation of the antifungal DADS was utilized in a murine candidiasis model, resulting in more efficient fungal clearance compared to the free formulation.

Synthesis and characterization of Schiff base octaazamacrocyclic complexes and their biological studies

A condensation reaction between 1,2-diphenylethane-1,2-dione dihydrazone (DPEDDH) and dimethyl or diethyloxalate in methanol resulted in a novel Schiff base octaazamacrocyclic ligand, (L): (6,7,14,15-tetraoxa-2,3,10,11-tetraphenyl-1,4,5,8,9,12,13,16-octaazacyclohexadecane-1,3,9,11-tetraene). Subsequently metal complexes of the type [MLX2] and [CuL]X2; (M=Mn(II), Co(II), Ni(II) and Zn(II); X=Cl or NO3) were synthesized by the reaction of the free macrocyclic ligand (L) with the corresponding metal salts in 1:1 molar ratio. These complexes were characterized on the basis of analytical data, molar conductivity and magnetic susceptibility measurements, ESI-mass, IR, NMR ((1)H and (13)C), EPR and electronic spectral studies. The thermal stability of the complexes was also studied by TGA and DTA analyses. These studies show that all the complexes have octahedral arrangement around the metal ions except copper complexes which are square planar. The ligand and its complexes were screened for their antibacterial activity in vitro against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and were also studied for their anticancer activity against the human cancer cells lines: HeLa (Human cervical carcinoma), MCF7 (Human breast adenocarcinoma) and Hep3B (Human Hepatocellular carcinoma). The recorded IC50 values for the tested compounds show moderate to good cytotoxicity against these cancer cell lines. The copper complex, [CuL]Cl2, showed excellent antimicrobial activity against tested microorganisms which is almost equivalent to the standard drug ciprofloxacin.

Efficacy of niosomal formulation of diallyl sulfide against experimental candidiasis in Swiss albino mice

AIM We developed a niosomal formulation of diallyl sulfide (DAS), a garlic oil component, and evaluated its efficacy against experimental candidiasis in mice. METHODS DAS-bearing niosomes prepared from sorbitan monoester surfactants were evaluated for drug entrapment efficiency, release kinetics, toxicity, size, zeta-potential and others. Mice challenged with Candida albicans were treated with various DAS formulations. The efficacy of the formulations was assessed on the basis of reduction in mortality and decrease in residual fungal load in vital organs, such as liver and spleen, of treated mice. RESULTS Niosomal DAS (12 mg/kg body weight) significantly reduced fungal load and mortality in treated animals compared with the free form of DAS. Niosomal DAS was also found to be free of toxic manifestations, as revealed by histopathological studies, as well as liver/kidney function tests. CONCLUSION Incorporation of DAS in niosomes enhances its antifungal efficacy. Further studies are needed to optimize the current findings to develop an efficient nature-derived alternative antifungal therapeutic strategy.

Escheriosome mediated cytosolic delivery of Candida albicans cytosolic proteins induces enhanced cytotoxic T lymphocyte response and protective immunity.

Protection against intracellular fungal infections, in a manner similar to viral challenges necessitates activation of both humoral and cell mediated immune responses in unison. Most of the presently available antigen delivery vehicles including egg phosphatidyl-choline (egg-PC) liposomes, can evoke mainly humoral immune responses in the immunized animals. Keeping this fact into consideration, we earlier developed Escherichia coli membrane lipid vesicles (escheriosomes) and demonstrated that escheriosomes successfully fuse with the plasma membrane of macrophages ensuing in effective cytoplasmic delivery of entrapped antigen, a pre-requisite for inducing CD8(+) T cell response against antigens. In the present study, we report the ability of escheriosomes encapsulated Candida albicans (C. albicans) cytosolic antigens (cAg), to generate protective immunity against systemic C. albicans infection in BALB/c mice. The immunization schedule using escheriosome encapsulated cAg induced strong antigen-specific CD8(+) T-cell responses, which were markedly higher than that observed in mice immunized with IFA-antigen emulsion, or antigen encapsulated in egg PC liposomes. Interestingly, immunization with cAg delivered in escheriosomes was also successful in complete elimination of C. albicans infection in Balb/c mice. The study suggests that escheriosomes may function as a novel immunoadjuvants and emerge as an effective tool for generating protective immunity against C. albicans infection.

Efficacy of amoxicillin bearing microsphere formulation in treatment of Listeria monocytogenes infection in Swiss albino mice.

The present study deals with the evaluation of the efficacy of amoxicillin bearing poly-lactic-glycolic acid (PLGA) microsphere formulation in treatment of experimental listeriosis in Swiss albino mice. Amoxicillin bearing PLGA microspheres were prepared by water-in-oil-in-water emulsion technique. PLGA microwspheres significantly regulated sustained release of encapsulated drug over extended time period. The rate of release increased in temperature dependent manner. Amoxicillin bearing PLGA microsphere successfully cleared bacterial burdens in vital organs (kidney, spleen, and brain) and also increased survival rate of treated animals in comparison to free form of the drug. The higher efficacy of microsphere based novel formulation of amoxicillin could be attributed to its targeted delivery to infected macrophages as well as sustained release over extended period of time.

Safety, efficacy and pharmacokinetics of tuftsin-loaded nystatin liposomes in murine model

Present study was performed to evaluate the efficacy, toxicity and pharmacokinetics of antifungal drug nystatin incorporated in immunomodulator tuftsin-bearing liposomes. In vitro toxicity of free nystatin and nystatin incorporated in tuftsin-free or tuftsin-loaded liposomes was assessed by incubation of nystatin formulations with human erythrocytes. The toxicity profile of free nystatin and liposomal formulations of nystatin with or without tuftsin was also analyzed by monitoring the level of blood urea nitrogen (BUN) and serum creatinine in the treated BALB/c mice. The results of the present work showed that tuftsin-loaded nystatin liposomes like conventional nystatin liposomes exerted less toxicity to human erythrocytes as compared with free nystatin. Moreover, mice treated with tuftsin-loaded nystatin liposomes showed insignificant elevation in the biochemical values of serum creatinine and blood urea. The stability of nystatin liposomes upon incorporation of tuftsin was evaluated by monitoring the leakage of the entrapped drug in human serum. Tuftsin-loaded liposomes held nystatin for longer duration in the presence of serum than identical nystatin liposomes without tuftsin. Pharmacokinetics of the both tuftsin-free or tuftsin-loaded liposomal formulations nystatin was analyzed by determining the level of nystatin in the systemic circulation of mice at different time points. Mice injected with tuftsin-loaded nystatin liposomes showed higher level of the drug in the systemic circulation compared with those treated with conventional nystatin liposomes. The efficacy of tuftsin-loaded nystatin liposomes against A. fumigatus was evaluated by assessing the fungal burden in the lungs of treated mice. Treatment with tuftsin-loaded nystatin liposomes was most effective in eliminating fungal burden from lung tissues of infected mice compared to those treated with free nystatin or nystatin liposomes without tuftsin. The immunopotentiating activity, increased stability and less toxicity of tuftsin-incorporated nystatin liposomes, supports the idea for its prophylactic and therapeutic use in the clinical setting.

Prophylactic Role of Liposomized Chloroquine Against Murine Cryptococcosis Less Susceptible to Fluconazole

No HeadingPurpose.The prophylactic role of liposomized chloroquine (lip-CQ) has been assessed against less susceptible Cryptococcus neoformans infection in murine model.Methods.In the current study, we investigated the antifungal activity of lip-CQ against C. neoformans in macrophages cell line (J 774) and murine model. Mice were pretreated with free as well as liposomized formulations of CQ at various doses. The anticryptococcal activity of fluconazole was compared in mice with or without CQ pretreatment. The efficacy of CQ prophylaxis was assessed by survival as well as colony forming units (cfu) in brain and lungs of treated mice.Results.Fluconazole alone was not found significantly effective against C. neoformans in both in vitro and in vivo studies. However, the antifungal activity of fluconazole increases in chloroquine-pretreated mice. Lip-CQ was found to be more effective in comparison to the same dose of free chloroquine in reducing fungal burden from macrophages in vitro and lungs and brain of C. neoformans infected mice.Conclusions.The enhanced prophylactic activity of lip-CQ seems due to rapid uptake of drug-containing liposomes by macrophages. The liposome-mediated accumulation of CQ in macrophages makes the environment unfavorable (alkaline) for the intracellular multiplication of C. neoformans. Moreover, the increased incidence of multidrug resistance and diversity of pathogenic microorganisms inhibited or killed by CQ makes it the drug of choice for prophylactic therapy.

TLR Agonist Augments Prophylactic Potential of Acid Inducible Antigen Rv3203 against Mycobacterium tuberculosis H37Rv in Experimental Animals

In general, the members of Lip gene family of Mycobacterium tuberculosis evoke strong immune response in the host. Keeping this fact into consideration, we investigated role of Rv3203, a cell wall associated protein with lipolytic activity, in imparting protection against experimental murine tuberculosis. The data of the present study suggested that archaeosome encapsulated Rv3203 induce strong lymphocyte proliferation, up-regulated Th-1 biased cytokines profile, increased expression of co-stimulatory markers on both antigen presenting cells and T lymphocytes. The immuno-prophylactic response was further modulated by exposure of the animals to zymosan, a TLR2/6 agonist, prior to immunization with archaeosome encapsulated Rv3203. Interestingly, pre-treatment of experimental animals with zymosan boosted strong immunological memory as compared to archaeosome encapsulated Rv3203 as well as BCG vaccine. We conclude that priming of immunized animal with TLR agonist followed by immunization with archaeosomes encapsulated Rv3203 offer substantial protection against tuberculosis infection and could be a potential subunit vaccine based prophylactic strategy.