The role of LPD-nanoparticles containing recombinant major surface glycoprotein of Leishmania (rgp63) in protection against leishmaniasis in murine model.

CONTEXT: Leishmaniasis is a major public health problem. Despite numerous attempts, yet there is no effective vaccine against human leishmaniasis, mainly due to a lack of an effective vaccine delivery system as well as adjuvant. OBJECTIVE(S): The aim of this study was to evaluate the ability of recombinant glycoprotein 63 (rgp63) as a model of Leishmania antigen, entrapped in liposome-polycation-DNA (LPD) complexes nanoparticles in inducing cell mediated immune (CMI) response and protecting against L. major in BALB/c mice. MATERIALS AND METHODS: To this end, the abundant leishmania promastigote cell surface glycoprotein, gp63, was entrapped in nano-sized LPD (CpG) particles, (LPD (CpG)-rgp63), and BALB/c mice were immunized three times with either (LPD (CpG)-rgp63) or rgp63-CpG DNA or LPD (CpG) or free rgp63 and dextrose 5%. Various parameters including footpad thickness, splenic load of L. major parasites, rgp63-binding IgGs and also cytokine levels of rgp63-reactive T lymphocytes were then compared among different vaccinated animals. RESULTS: The lowest number of parasites in spleen, the higher levels of IgG2a after challenge infection, the minimal footpad swelling and high level of IFN-γ secretion, all indicated that adjuvants and antigen-delivery systems are essential in modifying immune responses; as mice received LPD (CpG)-rgp63 induced immune response stronger than the other groups. CONCLUSIONS: This study demonstrates that LPD nanoparticle is a promising and adaptable delivery system which could be modified towards specific vaccine targets to induce a more potent immune response in combination with rgp63.

The role of liposome size on the type of immune response induced in BALB/c mice against leishmaniasis: rgp63 as a model antigen.

To develop an efficient liposomal vaccine delivery system, the size of liposomes is critical to their adjuvant activities. In the present study, liposomes with different sizes (100, 400, 1000 nm) containing recombinant major surface glycoprotein of Leishmania (rgp63) were prepared, characterized, and inoculated subcutaneously into BALB/c mice to evaluate the rate of protection and the type of immune response generated against leishmaniasis. The lowest footpad lesion size and splenic parasite burden were seen in the mice immunized with large size (≥400 nm) liposomes after challenge with Leishmania major. The production of IFN-γ was only elevated in the spleen cells of mice immunized with large size (≥400 nm) liposomes. The highest IgG2a/IgG1 ratio was also seen in the sera of the mice immunized with large size (≥400 nm) liposomes before and 14 weeks after challenge. The results showed that immunization with small size (100 nm) liposomes induces a Th2 response, whereas immunization with large size (≥400 nm) liposomes induces a Th1 type of immune response. There was no significant difference in the type of induced immune response between the mice immunized with liposomes of 400 nm and those immunized with liposomes of 1000 nm or unextruded. The results of the current study demonstrated that the size of liposomes plays a significant role in the type of generated immune response.

Effect of topical liposomes containing paromomycin sulfate in the course of Leishmania major infection in susceptible BALB/c mice.

The aim of this study was to evaluate the antileishmanial effects of topical liposomal paromomycin sulfate (PM) in Leishmania major-infected BALB/c mice. Liposomes containing 10 or 15% PM (Lip-PM-10 and Lip-PM-15, respectively) were prepared by the fusion method and were characterized for their size and encapsulation efficiency. The penetration of PM from the liposomal PM formulations (LPMFs) through and into skin was evaluated in vitro with Franz diffusion cells fitted with mouse skin at 37 degrees C for 8 h. The in vitro permeation data showed that almost 15% of the LPMFs applied penetrated the mouse skin, and the amount retained in the skin was about 60% for both formulations. The 50% effective doses of Lip-PM-10 and Lip-PM-15 against L. major promastigotes in culture were 65.32 and 59.73 microg/ml, respectively, and those against L. major amastigotes in macrophages were 24.64 and 26.44 microg/ml, respectively. Lip-PM-10 or Lip-PM-15 was used topically twice a day for 4 weeks to treat L. major lesions on BALB/c mice, and the results showed a significantly (P < 0.001) smaller lesion size in the mice in the treated groups than in the mice in the control group, which received either empty liposomes or phosphate-buffered saline (PBS). Eight weeks after the beginning of the treatment, every mouse treated with LPMFs was completely cured. The spleen parasite burden was significantly (P < 0.001) lower in mice treated with Lip-PM-10 or Lip-PM-15 than in mice treated with PBS or control liposomes, but no significant difference was seen between the two groups treated with either Lip-PM-10 or Lip-PM-15. The results suggest that topical liposomal PM may be useful for the treatment of cutaneous leishmaniasis.

Preparation, characterization, and in vivo evaluation of nanoliposomes-encapsulated bevacizumab (avastin) for intravitreal administration.

PURPOSE: Intravitreal injections can cause several ocular complications, including vitreous hemorrhage, endophthalmitis, retinal detachment, and cataract, and clearly repeated injections can multiply the risk of these complications. Bevacizumab is used for the treatment of different ocular diseases. For improvement of drug availability after intravitreal administration, in this study, liposomal bevacizumab as a novel drug delivery system was prepared and compared with conventional formulas in the market. METHODS: Bevacizumab was encapsulated into liposomes via the dehydration-rehydration method. After reducing the size of liposome to the nanoscale, the final liposomal formulation was tested in an animal model. Left eyes of rabbits received liposomal bevacizumab and the right eyes were injected by soluble bevacizumab. The free drug concentration in aqueous humor and vitreous samples at Days 3, 7, 14, 28, and 42 after the injection was determined by enzyme-linked immunosorbent assay. RESULTS: Mean concentration of free bevacizumab in the eyes that received liposomal bevacizumab compared with the eyes injected with soluble bevacizumab was 1 (48 versus 28 microg/mL) and 5 (16 versus 3.3 microg/mL) times higher at Days 28 and 42, respectively. Mean concentration of free bevacizumab in the aqueous humor of both injected eyes was almost the same at the different intervals. CONCLUSION: The results of this study showed the beneficial effects of liposomes in prolonging the residency of bevacizumab in the vitreous.

The role of liposome charge on immune response generated in BALB/c mice immunized with recombinant major surface glycoprotein of Leishmania (rgp63).

Liposomes as a lipid-based system have been shown to be an effective adjuvant formulation. In this study, the role of liposome charge in induction of a Th1 type of immune response and protection against leishmaniasis in BALB/c mice was studied. Liposomes containing rgp63 were prepared by Dehydration-Rehydration Vesicle (DRV) method. Neutral liposomes consisted of dipalmitoylphosphatidylcholine and cholesterol. Positively and negatively charged liposomes were prepared by adding dimethyldioctadecylammonium bromide (DDAB) or dicetyl phosphate (DCP) to the neutral liposome formulation, respectively. Female BALB/c mice were immunized subcutaneously with negatively, positively charged or neutral liposomes encapsulated with rgp63, rgp63 in soluble form or PBS, three times in 3week intervals. The extent of protection and type of immune response generated were studied in different groups of mice. The group of mice immunized with rgp63 encapsulated in neutral liposomes showed a significantly (P<0.01) smaller footpad swelling upon challenge with Leishmania major compared with positively or negatively charged liposomes. The mice immunized with neutral liposomes also showed a significantly (P<0.01) the lowest splenic parasite burden, the highest IgG2a/IgG1 ratio and IFN-gamma production and the lowest IL-4 level compared to the other groups. The results indicated that a Th1 type of immune response was induced in mice immunized with neutral liposomes more efficiently than positively charged liposomes and conversely negatively charged liposomes induced a Th2 type of immune response.

Common features of tuberculosis and sarcoidosis.

Tuberculosis (TB) is a disease caused by Mycobacterium tuberculosis. Despite the availability of novel therapeutic approaches, TB is considered as one of the leading causes of death due to infectious diseases worldwide. Alveolar macrophages are the first line of defense against M. tuberculosis; they ingest and sequester the bacilli within granulomatous structures. Control and resolution of the infection requires activated T lymphocytes as well as Th1 cytokines. There are two forms of TB: active TB and latent TB. Latent TB is a state in which M. tuberculosis survives in the body without causing overt signs and symptoms. People with latent TB are noncontagious. However, M. tuberculosis can become active in the body, multiply, and cause overt TB. Sarcoidosis, on the other hand, is an autoimmune disease of unknown etiology which can affect multiple systems of the body. Nonspecific constitutional symptoms, such as fever, fatigue, malaise, and weight loss, are present in approximately one-third of patients. Chest X-ray usually shows hilar and mediastinal lymphadenopathy. Although the lungs are the most common sites of inflammation, sarcoidosis can also involve other organs, such as the eyes (intraocular and adnexal), skin, lymph nodes, salivary glands, heart, spleen, liver, and the nervous system. Recent investigations have provided further insights into the genetic basis of sarcoidosis and the way genotype determines the clinical presentation and phenotype of patients. Histopathologic features are usually insufficient for diagnosis of sarcoidosis. Diagnosis of sarcoidosis in endemic areas for TB can become a great challenge. Both TB and sarcoidosis are granulomatous diseases; TB is characterized by caseating granulomas, whereas sarcoidosis is characterized by noncaseating granulomas. New cases of sarcoidosis are increasingly being diagnosed in areas endemic for TB due to increased orientation of physicians and availability of diagnostic modalities. However, it is often difficult to differentiate sarcoidosis from TB, especially when caseous necrosis is not seen and acid-fast staining is negative in the biopsy specimen of patient with TB. Granulomatous inflammation in sarcoidosis is believed to be caused by the presence of a persistent poorly degradable unknown antigen in combination with a nonresolving host response. M. tuberculosis has been extensively studied as a possible cause of sarcoidosis. Results suggest that granulomas form in the lungs as a result of the immune response to inhaled M. tuberculosis and serve as the central site of host-pathogen interaction during M. tuberculosis infection. M. tuberculosis DNA detection in sarcoidosis samples by traditional polymerase chain reaction (PCR) has been used for the pathological study of sarcoidosis; however, it is likely that real time quantitative PCR analysis of specific mRNAs and microRNAs will be necessary as a sensitive, precise, and rapid diagnostic test for detecting trace of TB in Sarcoidosis. In conclusion, diagnosis of sarcoidosis in areas with a high burden of TB poses a significant challenge. Improved diagnostic tests including genetic tests can improve our knowledge and help in distinguishing these two diseases.

Association of serum TNF-α, IL-8 and free light chain with HLA-DR B alleles expression in pulmonary and extra-pulmonary sarcoidosis.

BACKGROUND: Sarcoidosis is a systemic disease of unknown etiology characterized histologically by the observation of non-caseating granulomas and several immunological abnormalities. Sarcoidosis is a multi-organ disorder which involves formation of granulomas in many tissues including the lungs (pulmonary) and others such as skin, bone, heart (extra pulmonary). Associations between human leukocyte antigens (HLA), the encoded cell surface receptor (HLA-DR) and sarcoidosis have been reported in several studies. Several HLA-DR alleles have been described as potential risk factors for sarcoidosis in distinct ethnic groups however evidence for a relationship between HLA-DR alleles and pulmonary and extra-pulmonary sarcoidosis (EPS) is still scarce. Although the etiology of the disease remains unclear, infectious and environmental factors have been postulated. Inflammatory cytokines and chemokines may play important roles in the pathogenesis of sarcoidosis and serum free light chain (FLC) numbers have been implicated in several immunologic disorders. PURPOSE OF THE STUDY: The aim of the present study was to investigate HLA associations with serum cytokines and FLC in Iranian patients with pulmonary (n = 86) and EPS (n = 46). RESULTS: We found that among the 16 HLA DRB alleles only *7 and *12 were different in sarcoidosis patients. The levels of TNF-α and IL-8 in pulmonary sarcoidosis patients were higher than in EPS (P < 0.05) whereas the levels of FLC subunits in EPS were higher than in pulmonary sarcoidosis. CONCLUSION: This data may suggests a link between HLA-DRB *12 and sarcoidosis in Iranian population.

Enhancement of immune response and protection in BALB/c mice immunized with liposomal recombinant major surface glycoprotein of Leishmania (rgp63): the role of bilayer composition.

Development of new generation vaccines requires adjuvants to elicit the type and intensity of immune response needed for protection. Liposomes have been shown to be an effective adjuvant formulation. In this study, the role of liposome bilayer composition with different phase transition temperature (T(c)) to induce a T helper 1 (Th1) type of immune response and protection against leishmaniasis in BALB/c mice was assessed. Liposome formulations with different bilayer compositions consisting of egg phosphatidylcholine (EPC, T(c)<0 degrees C), dipalmitoylphosphatidylcholine (DPPC, T(c) 41 degrees C), or distearoylphosphatidylcholine (DSPC, T(c) 54 degrees C) were prepared. All liposomes were contained rgp63 as a recombinant antigen and used to immunize mice subcutaneously 3 times in 3-week intervals. Evaluation of lesion development and splenic parasite burden after challenge with L. major, evaluation of Th1 cytokine (IFN-gamma) and Th2 cytokine (IL-4), and titration of IgG isotypes were carried out to assess the type of generated immune response and extent of protection. The results indicated the generated immune response in mice was influenced by the bilayer composition of liposomes, so that mice immunized with liposomes consisting of EPC induced a Th2 type of immune response while liposome consisting of DPPC or DSPC induced Th1 type of immune response. It seems that liposomes prepared with higher Tm phospholipids are suitable formulation to induce Th1 type of immune response and protection, and so might be used for further investigations to develop an effective vaccine against leishmaniasis.

Coencapsulation of CpG oligodeoxynucleotides with recombinant Leishmania major stress-inducible protein 1 in liposome enhances immune response and protection against leishmaniasis in immunized BALB/c mice.

CpG oligodeoxynucleotides (CpG ODN) have been shown to have potent adjuvant activity for a wide range of antigens. The purpose of this study was to determine the potential benefit of using liposomes as a delivery vehicle to enhance the adjuvant activity of CpG ODN with Leishmania major stress-inducible protein 1 (LmSTI1) antigen in induction of the Th1 response in a murine model of leishmaniasis. BALB/c mice were immunized subcutaneously three times in 3-week intervals with liposomal recombinant LmSTI1 (Lip-rLmSTI1), rLmSTI1 coencapsulated with CpG ODN in a liposome (Lip-rLmSTI1-CpG ODN), rLmSTI1 plus CpG ODN in phosphate-buffered saline (PBS), rLmSTI1 plus non-CpG ODN in PBS, rLmSTI1 in PBS, empty liposome, or PBS. The intensity of infection induced by L. major promastigote challenge was measured by footpad swelling. A significant (P < 0.001) inhibition of infection in mice immunized with Lip-rLmSTI1-CpG ODN was shown compared to the other groups, and no parasite was detected in the spleens of this group 14 weeks after challenge. The highest immunoglobulin G2a (IgG2a) titer and the highest IgG2a/IgG1 ratio were also shown in the sera of mice immunized with Lip-rLmSTI1-CpG ODN before and 14 weeks after challenge. The results indicated the superiority of CpG ODN in its liposomal form over its soluble form to induce the Th1 response when used in association with rLmSTI1 antigen. It seems that using a liposome delivery system carrying CpG ODN as an adjuvant coencapsulated with Leishmania antigen plays an important role in vaccine development strategies against leishmaniasis.

The role of CpG ODN in enhancement of immune response and protection in BALB/c mice immunized with recombinant major surface glycoprotein of Leishmania (rgp63) encapsulated in cationic liposome.

CpG oligodeoxynucleotides (CpG ODN) are known to be a potent immunoadjuvant for a wide range of antigens. The aim of this study was to evaluate the role of CpG ODN co-encapsulated with rgp63 antigen in cationic liposomes (Lip-rgp63-CpG ODN) in immune response enhancement and protection in BALB/c mice against leishmaniasis. Lip-rgp63-CpG ODN prepared by using dehydration-rehydration vesicle (DRV) method significantly inhibited (P<0.001) Leishmania major infection in mice measured by footpad swelling compared to Lip-rgp63, rgp63 alone, rgp63 plus CpG ODN, PBS or control liposomes. The mice immunized with Lip-rgp63-CpG ODN also showed the lowest spleen parasite burden, highest IgG2a/IgG1 ratio and IFN-gamma production and the lowest IL-4 production compared to the other groups. The results indicate that co-encapsulation of CpG ODN in liposomes improves the immunogenicity of Leishmania antigen.