Quantitative proteomic analysis of cellular responses to a designed amino acid feed in a monoclonal antibody producing Chinese hamster ovary cell line

Background: Chinese hamster ovary [CHO] cell line is considered as the most common cell line in the biopharmaceutical industry because of its capability in performing efficient post-translational modifications and producing the recombinant proteins, which are similar to natural human proteins. The optimization of the upstream process via different feed strategies has a great impact on the target molecule expression and yield

Methods: To determine and understand the molecular events beneath the feed effects on the CHO cell, a label-free quantitative proteomic analysis was applied. The proteome changes followed by the addition of a designed amino acid feed to the monoclonal antibody producing CHO cell line culture medium were investigated

Results: The glutathione synthesis, the negative regulation of the programmed cell death, proteasomal catabolic process, and the endosomal transport pathway were up-regulated in the group fed with a designed amino acid feed compared to the control group

Conclusion: Our findings could be helpful to identify new targets for metabolic engineering

Development of Genetically Modified Chinese Hamster Ovary Host Cells for the Enhancement of Recombinant Tissue Plasminogen Activator Expression

Background: Chinese hamster ovary (CHO) cells are the most commonly used host system for the expression of high quality recombinant proteins. However, the development of stable, high-yielding CHO cell lines is a major bottleneck in the industrial manufacturing of therapeutic proteins. Therefore, different strategies such as the generation of more efficient expression vectors and establishment of genetically engineered host cells have been employed to increase the efficiency of cell line development. In order to examine the possibility of generating improved CHO host cells, cell line engineering approaches were developed based on ceramide transfer protein (CERT), and X-box binding protein 1s (XBP1s). Methods: CHO cells were transfected with CERT S132A, a mutant variant of CERT which is resistant to phosphorylation, or XBP1s expression plasmids, and then stable cell pools were generated. Transient expression of t-PA was examined in engineered cell pools in comparison to un-modified CHO host cells. Results: Overexpression of CERT S132A led to the enhancement of recombinant tissue plasminogen activator (t-PA) expression in transient expression by 50%. On the other hand, it was observed that the ectopic expression of the XBP1s, did not improve the t-PA expression level. Conclusion: The results obtained in this study indicate successful development of the improved CHO host cells through CERT S132A overexpression.

Effects of peptone supplementation in different culture media on growth, metabolic pathway and productivity of CHO DG44 cells; a new insight into amino acid profiles

The optimization of bioprocess conditions towards improved growth profile and productivity yield is considered of great importance in biopharmaceutical manufacturing. Peptones as efficient sources of nutrients have been studied for their effect on media development; however, their role on metabolic pathway is not well understood. In the present study, the effect of different concentration of peptones on a recombinant Chinese hamster ovary [CHO] cell line grown in three serum-free suspension cultures was determined. Six peptones of different origins and available amino acid profiles were investigated regarding their impact on cell growth, productivity, and metabolic pathways changes. In optimized feeding strategies, increases of 136% and 159% in volumetric productivity [for a low-nutrient culture media] and 55% [for a high-nutrient culture media] were achieved. Furthermore, particular sources of peptones with specific amino acid profile developed preferential results for each different culture medium. Two peptones, SoyA2SC and SoyE-110, were the only hydrolysates that showed production improvement in all three media. Casein Peptone plus Tryptone N1 and SoyA3SC showed different improved results based on their implemented concentration for each individual basal medium. The amino acid profile of peptones may provide clues to identify the most effective feeding strategies for recombinant CHO cells

Effect of peptone feeding on transient gene expression process in CHO DG44

Transient Gene Expression [TGE] gained popularity over the last decade as a rapid method for the production of milligram to gram quantities of recombinant proteins for preclinical studies in biophama industry. Thereby, the optimization of the TGE technique for Chinese hamster ovary [CHO] as the dominant host for the production of bio therapeutics is of great interest to reach the values for Human Embryo Kidney-293 [HEK-293] cells in terms of transfection efficiencies and production titers. TGE efficiencies are cell line and vector dependent. In transfection efficiency optimization experiments, different starting cell densities, different amounts of plasmid DNA and PEI transfection reagent were investigated to achieve the best conditions leading to maximum transfection efficiencies. Furthermore, in order to investigate the effect of peptone feeding on transfection efficiency, three different sources of peptones with the greatest effect in the CD DG44 basal media were selected; Casein Tryptone N1, Soy petone A2SC and Soy peptone E110. The transfection strategy performed here was able to make an outstanding increase in transfection efficiency of CHO DG44 cell line transfected with pTracer-SV40-mutated t-PA plasmid from 3.6% in our starting nonoptimized condition to 66.93% in finally optimized situation. Moreover, peptone feeding strategy used here was successful to increase volumetric productivities up to 37%. In addition, the amounts of both PEI and plasmid DNA were reduced up to 66% and 25%, respectively compared to our previous protocol. Here we described an optimization process for TGE in suspensionadapted CHO cells based on Polyethylenimine [PEI]/DNA concentration, DNA: PEI ratio, starting cell densities and peptone feeding strategy

role of different supplements in expression level of monoclonal antibody against human CD20

Recombinant monoclonal antibodies have been marketed in last three decades as the major therapeutic proteins against different cancers. However choosing a proper medium and supplements to reach the high expression is a challenging step. Despite of commercial serum free and chemically defined media, there are still numerous researches seeking the optimum media to gain higher expression titer. Selecting the best basal media followed by proper supplementation to increase the cell density and expression titer needs proper and accurate investigation. In this study, we have determined the expression titer of monoclonal antibody against human CD20 using soy extract, Essential Amino Acid, Non-Essential Amino Acid, Panexin NTS, Peptone, Yeast extract, Insulin-transferrin selenite, Human Serum Albumin, Bovine Serum Albumin, Lipid, and two commercially available supplements, Power and Xtreme feed. In each experiment, the expression level was compared with a well defined media, ProCHO5, RPMI 1640 and DMEM-F12. It has been shown that supplementing the ProCHO5 basal medium with 10% power feed or combination of 5% PanexinNTS,1.5 g/L yeast and 1.5g/L peptone results in the best production levels with 450 and 425 mg/L of anti CD20 mAb expression level, respectively. Panexin NTS, yeast and peptone cane be proper supplement for fed-batch cell culture instead of commercial Power feed supplement which is a cost effective way to increase expression level. And thereby ProCHO5 may be replaced with common media such as RPMI 1640 and DMEM-F12

novel approach for high level expression of soluble recombinant human parathyroid hormone [rhPTH 1-34] in escherichia coli

Parathyroid hormone [PTH] secreted by parathyroid glands regulates the metabolism of calcium and phosphorus in bone and kidney. Thereby, it can stimulate bone formation, and is a promising agent in the treatment of osteoporosis. Mature form of PTH consists of 84 amino acids; however, the first 34 residues of PTH cover the majority of hormonal action. In this study, the fusion form of highly soluble rhPTH was expressed at high level in Escherichia coli [E. coli]. His[6]-thioredoxin as an extension for rhPTH improves the solubility of inclusion body. His[6]-thioredoxin-hPTH [1-34] was ligated into pET32alpha expression vector. The insertion of 5 amino acids [Asp-Asp-Asp-Asp-Lys] in the N-terminal of PTH made this protein to be digestable specifically by enterokinase enzyme. The fusion form of rhPTH was harvested and purified by immobilized affinity chromatography followed by digestion with enterokinase. Digested rhPTH was purified by applying on size exclusion and ion exchange chromatography to get the highest purity. The mass spectroscopy analysis shows rhPTH molecular weight was 4117.5 Da. The purity was measured by HPLC column which showed more than 97%. Bioassay analysis of rhPTH was performed on rat sarcoma cell UMR-106 in parallel with commercially available rhPTH, Forteo. The result was measured through immunofluorescence detection kit. The data showed that the potency of rhPTH was comparable with commercially available medicine. Thioredoxin was applied as a fusion partner for production of highly soluble rhPTH. This specific fusion partner increased protein solubility and decreased protease reactivity. Purification process was optimized for high recovery and for purity more than 99%. As its biological activity is comparable with marketed drug, this protein is qualified for biopharmaceutical usage

Design of small molecules with HIV fusion inhibitory property based on Gp41 interaction assay

Gp41 of HIV [Human Immunodeficiency Virus] is a protein that mediates fusion between viral and cellular membranes. The agent, T-20, which has been approved for HIV inhibition, can restrain Gp41 function in the fusion process; nevertheless, it has disadvantages like instability, high cost of production and injection form to be delivered twice a day. Several molecules like NB-2 and NB-64 have been discovered that can inhibit HIV infection. These molecules were used as template compounds to design and develop more effective small molecules functioning as HIV-1 fusion inhibitors targeting Gp41. The process included in silico docking protocols using HEX and ArgusLab applications. A multisource database was created, after choosing the best molecules; they were tested in vitro for inhibitory activity by HIV-1 single-cycle model, transfected in HEK cells [293T]. Computational analysis and experimental data were combined to explore molecular properties and the most potent ones were found, with the best suitable criteria for interaction with Gp41. Several examples [DAA-6, DAA-9 and DAA-12] could inhibit infection in vitro as effective as NB-2, NB- 64. Since disadvantages of available fusion inhibitor [T-20], it seems necessary to find similar molecules to be approved and have small size providing suitable bioactivity profile. The molecules explored in this study can be good candidates for further investigations to be used as oral HIV fusion inhibitors in the future

[Enhancement of recombinant human tissue plasminogen activator expression in CHO cells using matrix attachment region containing vectors in combination with promoter activation strategy]

Development of high producing mammalian cell lines is a major bottleneck in manufacturing of recombinant therapeutic proteins. This study examines the effect of using the matrix attachment region from the human interferon beta gene in combination with promoter activation strategy with E1A 13S protein on human tissue plasminogen activator [t-PA] expression in Chinese hamster ovary [CHO] cells. The matrix attachment region was cloned in 3' and 5' flanking sides of the t-PA expression cassette in pTPA vector to generate pMTPA. After transfection of the cells with pTPA and pMTPA vectors, stable cell pools were developed and the t-PA expression level determined for each stable cell line. In the next step, E1A 13S expression plasmid was transfected to stable cell pools and t-PA titers were measured after 72 hours. Integration of pTPA and pMTPA vectors in the CHO genome was confirmed by PCR analysis on genomic DNA of stable cell pools. Analysis of the t-PA expression level showed a three-fold enhancement in pMTPA transfected cells compared to pTPAcontaining cells. t-PA expression was further enhanced up to 1771 U/ml by transient expression of E1A 13S in pMTPA stable cell pools. These results have shown that incorporation of matrix attachment region in an expression vector in combination with promoter activation can effectively enhance recombinant protein expression levels in CHO cells.

Immune responses against a new HIV-1 p24-gp41/pCAGGS-IL-12 DNA vaccine in balb/c mice

Development of an effective vaccine is highly needed in order to restrict the AIDS pandemic. DNA vaccines initiate both arms of immunity without the potential of causing disease. HIV-1 p24 and gp41 [gag and env] proteins play important roles in viral pathogenesis and are effective candidates for immune induction and vaccine design. In this study, new DNA vaccine candidates constructed from HIV-1 fused p24- gp41 or gp41 alone were evaluated in Balb/c mice for induction of cellular and humoral immune responses. Recombinant plasmids, pcDNA3.1/Hygro expression vector containing immunogenic sequences of fused p24-gp41 or gp41alone were produced. Dendrosome used as a system for carrying vectors in laboratory animals, and an IL-12 containing vector [pCAGGS-IL-12] was co-immunized with the p24-gp41 vector as a genetic adjuvant. Induction of effective immune responses against the designed vectors as DNA vaccine candidates in Balb/c mice was evaluated. Levels of total antibodies, IgG isotypes [IgG2a and IgG1]? IFN-alpha and IL-4 were measured by ELISA. MTT assay was used to evaluate lymphoproliferation. The results confirmed that the immunogenic epitopes of both p24 and gp41 genes are highly effective inducers of immune responses, and administration of fused p24-gp41 alone or along with IL-12 resulted in further enhancement of immune responses. Group 4 that received fused fragments [p24-gp41] along with an IL-12 expressing vector demonstrated a significantly higher Stimulation Index [SI] and IFN-alpha production [p<0.0001] with a significant increase in IgG2a/IgG1 ratio, indicating the stimulation of CMI towards Th1. Although gp41 containing vector [group 6] also showed significant increases in both proliferation and IFN-alpha production, the responses were persistently lower than that of p24-gp41 containing vectors. Total antibody production was highest in group 6 as expected. Dendrosome proved to be an efficient carrier of recombinant plasmids constructed in this study. Further studies are necessary to evaluate these constructs as HIV vaccine candidates

[ comparison of bone morphogenetic protein-7 mutant expression in prokaryotic and eukaryotic hosts]

Bone morphogenetic protein-7 [BMP-7] is a multifunctional growth factor predominantly recognized for its osteoinductive properties. Due to the high cost of this protein, the availability of BMP-7 for treatment is limited. The heterologous production of recombinant hBMP-7 has been performed in a number of expression systems. In this study a novel form of BMP-7 was expressed in eukaryotic and prokaryotic hosts. For expression in the prokaryotic system, the novel protein was secreted to the periplasmic space of Escherichia coli using a pelB signal sequence followed by singlestep purification by Ni2+-charged column chromatography. In the mammalian cell expression system, we transferred a full-length cDNA encoding precursor of the novel protein to CHO cells then selected stable clones by using the appropriate antibiotic concentration. Expressions in both systems were confirmed by Western blot analysis. The novel recombinant protein was produced as a 36-38 kDa dimer in the CHO cell line and a 16 kDa monomer in the Escherichia coli system. Quantitative analysis according to ELISA showed that the expression levels of the mutant protein in the eukaryotic and prokaryotic expression systems were 40 ng/ml and 135 ng/ml of the culture media, respectively. In this study, the expression level in Escherichia coli was at least three times more than observed in the CHO cells. However, further optimization is required to obtain a dimer protein in Escherichia coli. The results show that periplasmic expression may be suitable for the production of complex proteins such as BMPs

Periplasmic expression of a novel human bone morphogenetic protein-7 mutant in escherichia coli

Bone Morphogenetic Proteins [BMPs] belong to the transforming growth factor-beta [TGF-beta] superfamily, and play an important role in bone metabolism. Recombinant forms of BMP-2 and BMP-7 are the only BMPs used clinically. In this study the mature part of human bone morphogenetic protein-7 [BMP-7] was engineered through substitution of the BMP-7 Nterminal sequence by heparin-binding site of BMP-2. This targeted substitution was made to enhance the binding affinity of the novel protein to the extracellular matrix components such as heparin and heparan sulfate proteoglycans [HSPGs]. The engineered protein was expressed in Escherichia coli [E.coli]. The PelB signal sequence was used to translocate soluble proteins into the periplasmic space of E.coli. The protein was purified from periplasmic extract using Ni-NTA chromatography and the SDS-PAGE and western blot analysis confirmed the successful expression of the novel protein. The novel hBMP-7 mutant was produced as approximately 16 kDa monomer. It was found that the heparin binding of this protein was approximately 50% more than that of the wild-type at a protein concentration of 500 ng/ml. The findings showed that the periplasmic expression may be suitable to produce complex proteins like BMPs

Medical biotechnology trends and achievements in Iran

A healthcare system has been the most important priority for all governments worldwide. Biotechnology products have affected the promotion of health care over the last thirty years. During the last several decades, Iran has achieved significant success in extending healthcare to the rural areas and in reducing the rates of infant mortality and increasing population growth. Biomedical technology as a converging technology is considered a helpful tool to fulfill the Iranian healthcare missions. The number of biotechnology products has reached 148 in 2012. The total sales have increased to 98 billion USD without considering vaccines and plasma derived proteins in 2012. Iran is one of the leading countries in the Middle East and North Africa in the area of Medical biotechnology. The number of biotechnology medicines launched in Iran is 13 products until 2012. More than 15 products are in pipelines now. Manufacturers are expecting to receive the market release for more than 8 products by the end of 2012. Considering this information, Iran will lead the biotechnology products especially in area of biosimilars in Asia after India in next three years. The present review will discuss leading policy, decision makers' role, human resource developing system and industry development in medical biotechnology

Human tissue plasminogen activator expression in Escherichia coli using cytoplasmic and periplasmic cumulative power

Tissue plasminogen activator [tPA] is a serine protease, which is composed of five distinct structural domains with 17 disulfide bonds, representing a model of high-disulfide proteins in human body. One of the most important limitations for high yield heterologous protein production in Escherichia coli [E. coli] is the expression of complex proteins with multiple disulfide bridges. In this study the combination of two distinct strategies, manipulated cytoplasm and native periplasm, was applied to produce the functional full length tPA enzyme in E. coli. Using a PelB signal peptide sequence at 5' site of tPA gene, the expression cassette was prepared and subsequently was transformed into a strain with manipulated oxidizing cytoplasm. Then the induction was made to express the protein of interest. The SDS-PAGE analysis and gelatin hydrolysis confirmed the successful expression of functional tPA. The results of this study showed that complex proteins can be produced in E. coli using the cumulative power of both cytoplasm and periplasm

[Study on co-administration of GM-CSF, IL-15 on the enhancement of the immunogenicity of HIV-1 P24-Nef expression vector in BALB/c mouse model]

Today, AIDS is considered as a global problem and many efforts to generate an effective vaccine against this disease have been made, but remain inconclusive. DNA vaccines are a member of the new generation of vaccines that can efficiently stimulate the immune system. However, recent findings indicate low immunogenicity for these vaccines and it is believed that these types of vaccines require strategies that could infer more immunogenicity. The employment of adjuvants could be considered as one of the most important methods involved. In this study, a DNA vaccine candidate for HIV P24-Nef is constructed and then using genetic adjuvants IL-15 and GM-CSF, cellular immune responses have been studied. In this study the gene structure of HIV P24-Nef in eukaryotic expression vector was constructed and expression vectors of IL-15 and GM-CSF were used as adjuvants. After inoculation of the candidate vaccine to BALB/c mice, cytokine patterns, lymphocytes proliferation and cytotoxicity were analyzed. Our findings indicate that candidate vaccine significantly stimulated cellular immune responses. The usage of IL-15 and GM-CSF as DNA adjuvants together and separately with candidate vaccine has strengthened cellular immune responses significantly. Co-administration of DNA adjuvants significantly increased cellular immune responses when the ratio of the vaccine dose was more than the adjuvants. The sequences that we selected as candidate vaccine demonstrated good immunogenicity in mouse model and co-administration of IL-15 and GM-CSF DNA adjuvants increased cellular immune response to DNA vaccine construct

[Evaluation of intramuscular versus intra-dermal inoculation of bacterial plasmid encoding nucleoprotein of influenza virus]

The use of bacterial plasmids carrying specific genes of pathogens as genetic vaccines is a relatively new technique for induction of cellular immune responses against microbial pathogens. Mechanisms of production of specific immune responses against these vaccines are not still completely understood. Therefore, it is necessary to examine various routes of inoculation to find the best way of immunization for specific antigens. In this research, intramuscular method of inoculation of influenza vaccine nucleoprotein [NP] encoding vector was compared with that of intra-dermal method. In this study, the ability of two different methods of immunization [intramuscular and intra-dermal] in induction of CTL responses as well as their efficiency in clearance of influenza virus from the lung of BALB/c mice was compared. Female BALB/c mice were immunized with influenza virus NP expressing plasmids on days 0, 14 and 28. CTL activity of mice was evaluated by lactate dehydrogenase technique two weeks after the last inoculation. In addition, the mice were challenged by live influenza virus and the viral titer was measured 4 days postchallenge in the lungs of animals. The results of experiments demonstrated that intramuscular immunization of mice induces a stronger CTL response. Mice immunized by intramuscular route also showed a higher ability in virus clearance from the lungs. Results of this study showed that different routes of immunization of influenza NP genetic vaccine induce different levels of cell-mediated immune responses and protection from the live virus

[Evaluation of immune responses from immunization of HIV-1 P24-Nef fusion peptide vaccine with monophosphoryl lipid A [MPL] in BALB/c mice]

Several vaccines against HIV have been investigated but none has been approved as an effective HIV vaccine. An approach that could induce stronger immune response against the pathogen is utilizing a multi-epitopic vaccine. This strategy was used in the design of several vaccines and resulted in improved immune responses. In this study a multi-epitopic fusion peptide including parts of HIV-1 Nef and P24 as a vaccine candidate was injected into mice and immune humoral responses measured with total antibody and IgG sub-classes using ELISA. Also measurement of cellular immune responses through evaluation of spleen cells proliferation response using MTT and cytotoxicity by LDH were performed. Finally, the cytokine pattern of IFN-gamma and IL-4 were also determined with ELISA. The results indicate that candidate vaccine stimulated mouse splenic lymphocyte proliferation response and also induced strong cytotoxicity responses. Analysis of humoral immune response has shown that the candidate vaccine has induced specific antibody production mainly of the IgG2a sub-class. Also cytokine pattern evaluation has shown that IFN-gamma secretion was dominant. The use of immunogen and conserved epitopes from P24 and Nef induced strong humoral and cellular immune responses and this construct could be candidate for further studies in animal models

Characterization of immune responses induced by combined clade-A HIV-1 recombinant adenovectors in mice

Numerous evidences indicate that in some HIV-1 positive patients, the humoral and cellular immune responses are induced against HIV-1 proteins and this is inversely related to the progress of infection. The aim of this study was the evaluation of the Adenovectors containing HIV genes in induction of immune responses in mice. The HIV-1 genes including gag p24, rev, nef and exon-1 of tat were amplified from HIV-1 RNA [clade-A]. The cDNA of each gene was cloned into a transfer vector. The transfer vector was then co-transformed into E. coli strain BJ5183 together with pAdenovector ?E1/E3. The recombinant adenoviral construct was transfected into QBI-293A cells. Recombinant viruses were purified and titrated on 293 cell plates. Expression of transgenes was evaluated using western blotting. Then 1012 viral particles were injected into 15 groups of 5 mice and all patterns of combination of these 4 HIV-1 genes were evaluated. After 2 weeks, humoral and cellular immune responses were evaluated using ELISA, cell proliferation and ELISpot [IL-2, IL-4 and IFN- gamma] assays, consecutively. It was demonstrated that each gene was expressed. The response targets were mostly toward Th1, though several Th2 responses were also observed. Single injection in our study induced a good cellular response but the humoral responses were not as strong as the cellular ones. Considering and comparing all results and evaluating the various possible interactions revealed that simultaneous injection of tat and gag has enhanced the humoral and cellular responses

Immunogenicity of a new HIV-1 DNA Construct in a BALB/c mouse model

Cell mediated immunity, especially cytotoxic T cell responses against HIV-1 infection, plays a critical role in controlling viral replication and disease progression. DNA vaccine is a novel technology which is known to stimulate strong cellular immune responses. Many DNA vaccines have been tested for HIV infection but there is still no effective vaccine against this infection. Construction of a vaccine consisting of multiple conserved and immunogenic epitopes may increase vaccine efficacy. In the present study a DNA vaccine candidate constructed from HIV-1 P24-Nef was evaluated and cellular immune responses were assessed in murine BALB/c model. HIV-1 P24-Nef gene was cloned in PCDNA3.1 expression vector. Mice were immunized with DNA construct and IL-4 and IFN-gamma evaluation was per-formed using ELISPOT. Cytotoxicity response was evaluated with Granzyme B ELIS-POT assay and lymphocyte proliferation was evaluated with LTT assay. Analysis of immune responses showed that, compared to control groups, the candidate vaccine induced production of higher levels of both IL-4 and IFN-gamma [p<0.05]. Cytotoxicity and lymphocyte proliferation responses of mice vaccinated with the candidate vaccine were significantly increased compared to control groups [p<0.05]. HIV-1 P24-Nef DNA construct displayed strong immunogenicity in a murine model

Application of SYBR-Green Real Time RT-PCR for quantification of human immunodeficiency virus type-1 [HIV-1] and comparison with COBAS AMPLICOR test

In this study, a SYBR Green real-time RT-PCR assay for quantification of HIV-1 viral RNA was developed. This assay was performed based on amplification of the pol region of HIV-1 and product analysis by an ABI 7500 system. We quantified HIV-1 viral load in 26_seropositive patients by this system and the data were subsequently compared with results obtained with a reference technique represented by COBAS AMPLICOR HIB-1 Monitor test. The results demonstrated that this technique could detect up to 500 HIV-1 RNA copies/ml of plasma. The linearity of this approach was conserved over a wide range of HIV-1 copy numbers [5x10[2]- 5x10[9]]. Since no positive signal was observed in seronegative volunteers, the specificity of the test was calculated as 100%. Comparison of the results with those obtained by the reference quantification method, revealed a significant correlation between the results [R[2] =0.95]. On the basis of the most recent recorded cases for HIV-1 infection and AIDS in Iran, the prevalence of this disease is rising rapidly and the situation has been called to be alarming by national health representatives. Determination of HIV-1 viral load in plasma has been considered as the most effective single prediction tool for monitoring HIV-1 patients treated with antiviral drugs. In this study, we have developed a SYBR-Green Real Time RT-PCR assay for quantitative analysis of HIV-1 in infected patients. Since a synthetic RNA standard was used in this assay, the upper limit of detection was detected to be higher than the standard test [5x10[9] versus 7.5x10[5]]. This can be important in patients with acute high viral load infections. Reproducibility was assessed by Intra assay and Inter assay analysis, Coefficient of variations Ct, in reproducibility tests for Intra assay and Inter assay variability were less than 3% and 4.5% accordingly. The above results, indicates that the new developed test can be a used in substitution of the commercial assay for quantitative analysis of HIV-1

Immune response analysis of immunized Balb/C mice with HIV-1 fusion p24 - gp41 genes as DNA vaccine candidate

The global HIV epidemic continues to expand and exceeding previous predictions. An effective vaccine represents the best hope to curtail the HIV epidemic. DNA vaccines induce humoral and cellular responses and mimic live vaccines without their pathogenic potential. The importance of CD8[+]CTL responses in controlling HIV and SIV viremia has led to production of a series of vaccines candidates that effectively induce these responses. It is now widely believed that an HIV vaccine strategy must stimulate both a strong humoral [antibody] as well as cell-mediated [CTL] immune response. The p24 and gp41 play many important roles in host-virus interaction and pathogenesis. These proteins are considered as attractive vaccine candidate in which their immunogenecity and immunomodulatory effects have been confirmed. In this study, a construct, pcDNA3.1Hygro- [p24-gp41], was evaluated as a DNA vaccine candidate in Balb/C mice for generation of effective cellular immune responses. For immunizing, we used dendrosome, a novel family of vehicles for transfection and therapy. IFN-gamma cytokine production and total antibody were detected by ELISA. Lymphoprolifration assay was performed by MTT test. ELISA and MTT assays confirmed that the cited p24-gp41 fusion gene is able to enhance immune responses in mice. The construct that was used in this research can be a good candidate for DNA vaccine against HIV-1, if the future complementary tests demonstrate the same trends of immunogenic responses shown in this study