Therapeutic targets and recent advances in protein immunotoxins

Targeted therapy has replaced the conventional methods of disease management with the advances in recombinant technology and increased understanding of molecular mechanisms of diseases. The immunotoxin strategy for diseases like cancer and a variety of autoimmune disorders has been used successfully in the past since its discovery. Since bacterial, fungal and plant toxins have various limitations like toxicity and immunogenicity, studies on fully humanized immunotoxins have gained attraction recently, which reduced toxicity significantly. Improved methods of antibody engineering have led to the emergence of various new formats of immunotoxins. This review summarizes the target moieties used in immunotoxin constructs in different diseases and describes the recent advances in immunotoxin targeting.     

Wet chemical synthesis of chitosan hydrogel–hydroxyapatite composite membranes for tissue engineering applications

Chitosan, a deacetylated derivative of chitin is a commonly studied biomaterial for tissue-engineering applications due to its biocompatibility, biodegradability, low toxicity, antibacterial activity, wound healing ability and haemostatic properties. However, chitosan has poor mechanical strength due to which its applications in orthopedics are limited. Hydroxyapatite (HAp) is a natural inorganic component of bone and teeth and has mechanical strength and osteoconductive property. In this work, HAp was deposited on the surface of chitosan hydrogel membranes by a wet chemical synthesis method by alternatively soaking the membranes in CaCl₂ (pH 7.4) and Na₂HPO₄ solutions for different time intervals. These chitosan hydrogel–HAp membranes were characterized using SEM, AFM, EDS, FT-IR and XRD analyses. MTT assay was done to evaluate the biocompatibility of these membranes using MG-63 osteosarcoma cells. The biocompatibility studies suggest that chitosan hydrogel–HAp composite membranes can be useful for tissue-engineering applications.     

Acute promyelocytic leukemia with unusual karyotype

Acute myeloid leukemia (AML-M3) is associated with the translocation t(15;17)(q22;q12-21) which disrupts the retinoic acid receptor alpha (RARA) gene on chromosome 17 and the PML gene on chromosome 15. We report a two-year-old patient with AML-M3 without the usual translocation t(15;17). Cytogenetic studies demonstrated normal appearance of chromosome 15 while the abnormal 17 homologue was apparently a derivative 17, der(17)(17qter-cen-q21:), the rearrangement distinctly shows deletion at 17q21 band and the morphology corresponding to an iso chromosome i(17q-). This case report is a rare cytogenetic presentation of acute promyelocytic leukemia (APML).     

Novel chitin/nanosilica composite scaffolds for bone tissue engineering applications

Biopolymers like chitin are widely investigated as scaffolds in bone tissue engineering. Its properties like biocompatibility, biodegradability, non-toxicity, wound healing ability, antibacterial activity, hemostatic property, etc., are widely known. However, these materials are not much bioactive. Addition of material like silica can improve the bioactivity and biocompatibility of chitin. In this work, chitin composite scaffolds containing nanosilica were prepared using chitin hydrogel and their bioactivity, swelling ability and cytotoxicity was analyzed in vitro. These scaffolds were found to be bioactive in simulated body fluid (SBF) and biocompatible when tested with MG 63 cell line. These results suggest that chitin/nanosilica composite scaffolds can be useful for bone tissue engineering applications.     

Induction and evaluation of atherosclerosis in New Zealand white rabbits

Atherosclerosis was experimentally induced in New Zealand white rabbits by feeding a high cholesterol diet for 12 weeks for screening of drugs against atherosclerosis. After 12 weeks, blood was collected from ear vein for evaluation of total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL) and very low density lipoprotein (VLDL) levels, then the animals were sacrificed to collect the livers for estimation of cholesterol, and aorta for gross and histopathological evaluations. The elevated levels of serum and liver parameters accompanied by gross and histopathological changes like accumulation of foam cells, atheromatous plaque formation and replacement fibrosis supported the successful induction of atherosclerosis in New Zealand white rabbits.     

Cytokine gene promoter polymorphisms and mortality in acute renal failure

BACKGROUND: Although cytokines play a pivotal role in the inflammatory responses that mediate the severity of acute renal failure (ARF), the importance of pro- and anti-inflammatory cytokine gene promoter polymorphisms has been unexplored. METHODS: We prospectively evaluated the relationship of single nucleotide polymorphism in the promoter region of tumor necrosis factor alpha (TNF-alpha) and interleukin-10 (IL-10) to mortality in 61 patients with ARF requiring intermittent hemodialysis. Cytokine genotyping was performed on leukocytes using PCR techniques. Cox proportional-hazards regression analysis was used to explore these relationships. RESULTS: The mean (+/-SD) APACHE II score was 24 +/- 7, MOF score 2 +/- 1, and 64% had sepsis. The TNF-alpha high producer genotype (-308 A-allele carrier) was associated with a higher risk of death after adjustment for the APACHE II score (HR=2.5; P=0.04), and the IL-10 intermediate/high producer genotype (-1082 G-allele carrier) was associated with a lower risk of death after adjustment for the MOF score (HR=0.36; P=0.03). Considering combinations of genotypes, the TNF-alpha high and IL-10 low producer genotype combination was associated with a approximately 6-fold increased risk of death compared to the TNF-alpha-low and IL-10 intermediate/high producer genotype combination, after adjustment for either APACHE II (P=0.004), MOF score (P=0.004) or sepsis (P=0.006). CONCLUSIONS: TNF-alpha and IL-10 gene polymorphisms are related to the risk of death among patients with ARF who require dialysis. Larger studies are needed to confirm these relationships.     

Proliferative responses of Brugia malayi TPX-1 and its epitopic peptide(29-43) in an endemic population of human lymphatic filariasis

Although the antioxidant thioredoxin peroxidase (TPX) is a putative target exploited in vaccine studies of lymphatic filariasis, the high sequence homology with host peroxiredoxins remains a great concern. The emergence of immunomics offers a powerful tool for novel vaccine design. Further, due to the cellular hypo-response in filariasis, analysis of T epitope repertoire becomes imperative in disease control. Here, we report the cellular responses of filarial TPX-1 and the identification of T epitope (29-43) in the host non-homologous region. The strong proliferative responses induced by the peptide mimetic in mice splenocytes and human PBMC's prove the existence of T epitope recognized in endemic population.     

Preparation and characterization of novel beta-chitin-hydroxyapatite composite membranes for tissue engineering applications

Beta-chitin is a biopolymer principally found in shells of squid pen. It has the properties of biodegradability, biocompatibility, chemical inertness, wound healing, antibacterial and anti-inflammatory activities. Hydroxyapatite (HAp) is a natural inorganic component of bone and teeth and has osteoconductive property. In this work, beta-chitin-HAp composite membranes were prepared by alternate soaking of beta-chitin membranes in CaCl2 (pH 7.4) and Na2HPO4 solutions for 2 h in each solution. After 1, 3 and 5 cycles of immersion, beta-chitin membranes were characterized using the SEM, FT-IR, EDS and XRD analyses. The results showed the presence of apatite layer on surface of beta-chitin membranes, and the amounts of size and deposition of apatite layers were increased with increasing number of immersion cycles. Human mesenchymal stem cells (hMSCs) were used for evaluation of the biocompatibility of pristine as well as composite membranes for tissue engineering applications. The presence of apatite layers on the surface of beta-chitin membranes increased the cell attachment and spreading suggesting that beta-chitin-HAp composite membranes can be used for tissue engineering applications.     

Identification of a highly immunoreactive epitope of Brugia malayi TPx recognized by the endemic sera

Filarial thiordoxin peroxidase is a major antioxidant that plays a crucial role in parasite survival. Although Brugia malayi TPx has been shown to be a potential vaccine candidate, it shares 63% homology with its mammalian counterpart, limiting its use as a vaccine or drug target. In silico analysis of TPx sequence revealed a linear B epitope in the host's nonhomologous region. The peptide sequence (TPx peptide(27-48)) was synthesized, and its reactivity with clinical sera from an endemic region was analyzed. The peptide showed significantly high reactivity (P < 0.05) against the sera of putatively immune individuals compared to the nonendemic control sera. It also showed high reactivity against the sera of patients with chronic pathology and patent infection. The high reactivity of the peptide with endemic immune sera equivalent to that of whole protein shows that it forms a dominant B epitope of TPx protein and thus could be utilized for incorporation into a multiepitope vaccine construct for filariasis.