Poly I: C-activated dendritic cells that were generated in CellGro for use in cancer immunotherapy trials

Background

For clinical applications, dendritic cells (DCs) need to be generated using GMP-approved reagents. In this study, we tested the characteristics of DCs generated in two clinical grade culture media and activated by three maturation stimuli, Poly I: C, LPS and the mixture of proinflammatory cytokines in order to identify the optimal combination of culture media and activation stimulus for the clinical use.

Method

We tested DCs generation using two GMP-certified culture media, CellGro and RPMI+5% human AB serum and evaluated DCs morphology, viability and capapability to mature. We tested three maturation stimuli, PolyI:C, LPS and the mixture of proinflammatory cytokines consisting of IL-1, IL-6, TNF and prostaglandin E2. We evaluated the capacity of activated DCs to induce antigen-specific T cells and regulatory T lymphocytes.

Results

Cell culture in CellGro resulted in a higher yield of immature DCs resulting from increased number of adherent monocytes. DCs that were generated in CellGro and activated using Poly I:C were the most efficient in expanding antigen-specific T cells compared to the DCs that were generated in other media and activated using LPS or the cocktail of proinflammatory cytokines. A comparison of all tested combinations revealed that DCs that were generated in CellGro and activated using Poly I:C induced low numbers of regulatory T cells.

Conclusion

In this study, we identified monocyte-derived DCs that were generated in CellGro and activated using Poly I:C as the most potent clinical-grade DCs for the induction of antigen-specific T cells.

Structural homology between elongation factors EF-Tu from Bacillus stearothermophilus and Escherichia coli in the binding site for aminoacyl-tRNA

Elongation factor EF-Tu (Mr approximately equal to 50 000) and elongation factor EF-G (Mr approximately equal to 78 000) were isolated from Bacillus stearothermophilus in a homogeneous form. The ability of EF-Tu to participate in protein synthesis is rapidly inactivated by N-tosyl-L-phenyl-alanylchloromethane (Tos-PheCH2Cl). EF-Tu X GTP is more susceptible to the inhibition by Tos-PheCH2Cl than is EF-Tu X GDP. Tos-PheCH2Cl forms a covalent equimolar complex with the factor by reacting with a cysteine residue in its molecule. The labelling of EF-Tu by the reagent irreversibly destroys its ability to bind aminoacyl-tRNA, which in turn protects the protein from this inactivation. This indicates that the modification of EF-Tu by Tos-PheCH2Cl occurs at the aminoacyl-tRNA binding site of the protein. To identify and characterize the site of aminoacyl-tRNA binding in EF-Tu, the factor was labelled with [14C]Tos-PheCH2Cl, digested with trypsin, the resulting peptides were separated by high-performance liquid chromatography and the sequence of the radioactive peptide was determined. The peptide has identical structure with an Escherichia coli EF-Tu tryptic peptide comprising the residues 75-89 and the Tos-PheCH2Cl-reactive cysteine at position 81 [Jonák, J., Petersen, T. E., Clark, B. F. C. and Rychlík, I. (1982) FEBS Lett. 150, 485-488]. Experiments on photo-oxidation of EF-Tu by visible light in the presence of rose bengal dye showed that there are apparently two histidine residues in elongation factor Tu from B. stearothermophilus which are essential for the interaction with aminoacyl-tRNA. This is clearly reminiscent of a similar situation in E. coli EF-Tu [Jonák, J., Petersen, T. E., Meloun, B. and Rychlík, I. (1984) Eur. J. Biochem. 144, 295-303]. Our results provide further evidence for the conserved nature of the site of aminoacyl-tRNA binding in elongation factor EF-Tu and show that Tos-PheCH2Cl reagent might be a favourable tool for the identification of the site in the structure of prokaryotic EF-Tus.

Graft survival and cytokine production profile after limbal transplantation in the experimental mouse model

Limbal transplantation or limbal stem cell (LSC) transfer represents the only way to treat severe ocular surface damage or LSC deficiency. However, limbal allografts are promptly rejected in spite of extensive immunosuppressive therapy. To characterize immune response after limbal transplantation, we established an experimental model of limbal transplantation in the mouse. Syngeneic, allogeneic and xenogeneic (rat) limbal grafts were grafted orthotopically in BALB/c mice and graft survival was evaluated. The presence of graft donor cells and the expression of IL-2, IL-4, IL-10, IFN-γ and inducible nitric oxide synthase (iNOS) mRNA in the grafts were detected by real-time PCR. While syngeneic grafts survived permanently, allografts were rejected in 9.0±1.8 days and xenografts in 6.5±1.1 days. The manifestation of clinical symptoms of rejection correlated with the disappearance of donor cells in the graft and in the recipient cornea. Intragraft expression of iNOS mRNA and distinct expression patterns of Th1 (IL-2, IFN-γ) and Th2 (IL-4, IL-10) cytokines were detected during rejection of limbal allografts and xenografts. The limbal graft rejection was prevented with anti-CD4, but not anti-CD8 monoclonal antibody therapy. The results indicate that limbal grafts do not enjoy immune privilege of the eye and are promptly rejected by Th1 (allografts) or by a combined Th1 and Th2 (xenografts) type of immune response involving CD4+ cells and iNOS expression. Targeting this pathway may be an effective way to prevent and treat limbal graft rejection.

Use of stabilometric platform and visual feedback in rehabilitation of patients after the brain injury

Rehabilitation of patients after the brain injury requires employing of all available mechanisms of neuroplasticity. To achieve it, the voluntary activation of brain systems that are involved in the signal processing, represents the most effective tool. The control of balance is a complex neuronal mechanism based on unconditioned and conditioned reflexes, as well as on the actual cognitive processes. As it requires participation of several brain regions, training of the posture support mechanisms can provide a highly effective tool for rehabilitation. The aim of the study was to develop methods for the long-term follow up and training of the balance skills in patients with different types of brain impairment. To obtain standard data, the stabilometric platform Posturograph STP-03 and special examination programs were also used in the study of the equilibrium skill training by healthy volunteers. For the assessment of the learning efficiency two criteria from the recorded data were used - the velocity of adjustment of the gravity centre and the accuracy of the movements. Stabilometric platform was used also for the balance skill training with the visual biofeedback. Our results show that the proposed program for the equilibrium skill training offers a comparatively simple method of the adequate duration with numerical and graphical output, which allows fast interpretation of the treatment results. The synoptic form of results can also stimulate the patient's motivation during the long-term training for the mobility improvement.

The influence of excessive stress on medical students in the Czech Republic - national sample

PURPOSE

The Czech Republic has been dealing with a long-term shortage of doctors, which, according to demographic forecasts, will continue to worsen due to the retirement of stronger generations of doctors in contrast to the gradual aging of the population, which will require more health care over time. The country´s political set is trying to respond to this shortage and demographic forecasts by gradually increasing financial funding of medical faculties with the aim of increasing the number of graduates of the program in the field of general medicine.

METHODS

Anonymous questionnaire survey was conducted among students and graduates of general medicine at all eight Czech medical faculties. A total of 3183 respondents participated in the survey. There were 2843 medical students, which represents approximately 28% of all medical students in the Czech Republic. The distribution of respondents within the study years was approximately even and approximately corresponded to the real distribution of students between individual faculties in country, which makes survey a national sample. The statistical processing was performed in the statistical software R. Apart from the basic comparison using percentage relative frequencies and Pearson´s chi-squared test, in this study we used Odds ratios (OR) with CI 0,95 from logistic regression model for a better interpretation of some outputs.

RESULTS

The results show that the vast majority of Czech medical students experience excessive stress during their studies, which increases the risk of students´ somatic problems (OR = 4.89, CI 0.95 = (4.11;5.83), p < 0.001)., targeted alcohol use (OR = 2.29, CI 0.95 = (1.73;3.04), p < 0,001) and the use of anxiolytic or antidepressant medication to reduce it (OR = 2.99, CI 0.95 = (2.24;4.01), p < 0.001). Students experiencing higher levels of excessive stress are more likely to leave their studies based on their own decision (4.20 (CI 0.95 (3.39;5.19), p < 0.001) and not to enter clinical practice after graduation (OR = 2.62, CI 0.95 = (2.06;3.33), p < 0.001).

CONCLUSIONS

The survey shows the need for an open discussion at the highest level about the possibilities of reasonable reduction of unnecessary stress during medical studies. Medical students in the Czech Republic are exposed to excessive stress with all the consequences described above. All that remains is to state the existence of unnecessary components of stress, which represent an opportunity to reduce it, thereby achieving better conditions for studying, improvement in the staff situation in the Czech healthcare system and a reduction in inefficiently spent financial resources for the education of young doctors.

TRIAL REGISTRATION

No registration.

[Characterization of null alleles in human histocompatibility complex antigens (HLA)]

The widespread application of DNA techniques in medicine and biology has allowed the typing of human leukocyte antigens (HLA) at the molecular level. Comparative studies between serological and molecular biology methods have shown the existence of null alleles, which code HLA antigens with low or no cell surface expression. Null alleles are not detectable by standard serological typing methods and may be overlooked/or incorrectly assigned by available DNA methods. Although null alleles are infrequent in human populations, they should not be ignored. Errors in typing of null alleles may cause complications in the evaluation of HLA matching of donor/recipient pairs that were originally considered HLA-compatible. The detection of null alleles and their frequency in various populations requires typing of a large number of individuals by both serological and DNA-based methods. Knowledge of the haplotype(s) associated with null alleles may be helpful for their identification. For this purpose, it is necessary to perform family studies.

Thymoma - disease of many faces

A thymoma belongs to rather rare tumors, although it holds the first place among primary mediastinal tumors in adults. The biological characteristics of thymomas are considerably divergent. The tumors are usually asymptomatic at the begining, later due to a local spread, symptoms from the infiltration or compression of adjacent structures arise, they metastasize rarely. Thymomas are often associated with various autoimmune or endocrinologic diseases. The authors present case of the patient with less common paraneoplasia - autoimmune hemolytic anemia (AIHA). Main strategy of treatment thymom with AIHA isn´t clear. The most important seems to be the early started corticotherapy. Achieving remission of secondary AIHA has importace in following therapy of thymoma - surgical resection or chemotherapy. Thymectomy has positive effect on the course of associated paraneoplastic syndromes and prognosis in general.

Glycopolymer Inhibitors of Galectin-3 Suppress the Markers of Tissue Remodeling in Pulmonary Hypertension

Pulmonary hypertension is a cardiovascular disease with a low survival rate. The protein galectin-3 (Gal-3) binding β-galactosides of cellular glycoproteins plays an important role in the onset and development of this disease. Carbohydrate-based drugs that target Gal-3 represent a new therapeutic strategy in the treatment of pulmonary hypertension. Here, we present the synthesis of novel hydrophilic glycopolymer inhibitors of Gal-3 based on a polyoxazoline chain decorated with carbohydrate ligands. Biolayer interferometry revealed a high binding affinity of these glycopolymers to Gal-3 in the subnanomolar range. In the cell cultures of cardiac fibroblasts and pulmonary artery smooth muscle cells, the most potent glycopolymer 18 (Lac-high) caused a decrease in the expression of markers of tissue remodeling in pulmonary hypertension. The glycopolymers were shown to penetrate into the cells. In a biodistribution and pharmacokinetics study in rats, the glycopolymers accumulated in heart and lung tissues, which are most affected by pulmonary hypertension.