Research on the conjugates of synthetic polyelectrolytes with antigenic molecules, such as proteins, peptides, or carbohydrates, is an attractive area due to their highly immunogenic character in comparison to classical adjuvants. For example, polyacrylic acid (PAA) is a weak polyelectrolyte and has been used in several biomedical applications such as immunological studies, drug delivery, and enzyme immobilization. However, to our knowledge, there are no studies that document immune-stimulant properties of PAA in Leishmania infection. Therefore, we aimed to develop a potential vaccine candidate against leishmaniasis by covalently conjugating PAA with an immunologically vital molecule of lipophosphoglycan (LPG) found in Leishmania parasites. In the study, LPG and PAA were conjugated by a multi-step procedure, and final products were analyzed with GPC and MALDI-TOF MS techniques. In cytotoxicity experiments, LPG-PAA conjugates did not indicate toxic effects on L929 and J774 murine macrophage cells. We assume that LPG-PAA conjugate can be a potential vaccine candidate, and will be immunologically characterized in further studies to prove its potential.

Some protozoan infections such as Toxoplasma, Cryptosporidium, and Plasmodium can be transmitted through stem cell transplantations. To our knowledge, so far, there is no study about transmission of Leishmania parasites in stem cell transplantation and interactions between parasites and stem cells in vitro. Therefore, the aim of this study was to investigate the interaction between different species of Leishmania parasites and adipose tissue-derived mesenchymal stem cells (ADMSCs). ADMSCs have been isolated, cultured, characterized, and infected with different species of Leishmania parasites (L. donovani, L. major, L. tropica, and L. infantum). Infectivity was examined by Giemsa staining, microculture, and polymerase chain reaction methods. As a result, infectivity of ADMSCs by Leishmania parasites has been determined for the first time in this study. According to our findings, it is very important that donors are screened for Leishmania parasites before stem cell transplantations in regions where leishmaniasis is endemic.

To determine the antileishmanial vaccine effectiveness of lipophosphoglycan (LPG) and polyacrylic acids (PAA) conjugates on in vivo mice models. LPG molecule was isolated and purified from large-scale Leishmania donovani parasite culture. Protection efficacies of LPG alone, in combination with Freund's adjuvant, in a physical mixture and in conjugate (consisting of various LPG concentrations) with PAA, were comparatively determined by various techniques, such as cultivation with the micro-culture method, assessment of in vitro infection rates of peritoneal macrophages, determination of parasite load in liver with Leishman-Donovan Units, and detection of cytokine responses. Obtained results demonstrated that the highest vaccine-mediated immune protection was provided by LPG-PAA conjugate due to all parameters investigated. According to the Leishman-Donovan Units results, the sharpest decline in parasite load was seen with a ratio of 81.17% when 35 μg LPG containing conjugate was applied. This value was 44.93% for the control group immunized only with LPG. Moreover, decreases in parasite load were 53.37%, 55.2% and 65.8% for the groups immunized with 10 μg LPG containing LPG-PAA conjugate, a physical mixture of the LPG-PAA, and a mixture of LPG + Freund's adjuvant, respectively. Furthermore, cytokine results supported that Th1 mediated protection occurred when mice were immunized with LPG-PAA conjugate. It has been demonstrated in this study that conjugate of LPG and PAA has an antileishmanial vaccine effect against visceral leishmaniasis. In this respect, the present study may lead to new vaccine approaches based on high immunogenic LPG molecule and adjuvant polymers in fighting against Leishmania infection.

The influence of coconut oil (CO) on a gelatin-based film was investigated when used as a potential wound dressing material. There is limited study on CO in protein-based wound dressing materials. Therefore, in this study a self-supporting, continuous and homogenous CO incorporated gelatin-based film was formulated and obtained by solution casting method. The influence of CO on physicochemical and thermal properties of gelatin-based film was also determined. Moreover, the effect CO in gelatin films on cell viability and cell migration was analysed with a preliminary cell culture study. Homogenous dispersion of 10% (w/w) CO was obtained in films when 3% (v/w) Tween 80, a surfactant, was incorporated to 20% (w/w) plasticized gelatin film forming solution. Effect of CO on gelatin-based film was observed via phase separation by scanning electron microscopy analysis. Water uptake of gelatin film with no CO, GE film; and 10% (w/w) CO incorporated GE film, GE-CO, were 320% and 210%, respectively, after 3 h in water. Fourier transform infrared spectroscopy analysis showed triglyceride component of CO and increased hydrogen bonding between NH groups of gelatin in GE-CO films. Differential scanning calorimetry results suggested a more ordered structure of GE-CO film due to an increase in melt-like transition temperature and melting enthalpy of GE-CO film. CO content also increased cell viability, assessed by XTT assay since cell viability was approximately 100% when L929 cell culture was incubated with GE-CO of 5–100 μg ml ⁻¹ . Moreover, GE-CO samples within 5–25 μg ml ⁻¹ concentration range, increased proliferation of L929 cells since cell viability was significantly higher than the 100% viable cell culture control ( P < 0.05) which is also an indication of efficient healing. However, GE decreased viability of L929 cells significantly at 100–10 μg ml ⁻¹ concentration range ( P < 0.05) and were toxic at concentrations of 100, 75 and 50 μg ml ⁻¹ which decreased ∼50% of the viability of the cells. Scratch Assay to assess in vitro wound healing showed cell migration towards scratch after 24 h as an indication of wound healing only in GE-CO samples. This study showed that, CO could efficiently be added to gelatin-based films for preparation of a primary wound dressing biomaterial which is also demonstrated to have a promising wound healing effect for minor wounds.