Showing 5 results for Immunogenicity
S. Takrim , M. Motamedi , M. Jafari , J. Amani , A.h. Salmanian ,
Volume 10, Issue 1 (3-2019)
Abstract
Newcastle disease virus (NDV) is an infectious agent of a large variety of birds, including chickens, which poses a real threat to the poultry industry. This virus is a member of the avian Paramyxoviridae. NDV is enveloped with membrane-embedded spikes consisting of glycosylated hemagglutinin (HN) and fusion (F) proteins. The mean death time after vNDV infection is 2-6 days, hence, the presence of preexisting antibodies prior to infection appears to be the most critical protection from this disease. Antibodies produced against the HN and F trans-membrane surface glycoproteins are able to neutralize NDV upon subsequent infection and inhibition of viral fusion with the host cell membrane, respectively. In this experimental study, the immunogenic epitopes of the F protein of NDV were designed artificially and were expressed in the heterologous system (Escherichia coli), using the appropriate vector (pET32a). In order to evaluate the immunogenicity of the recombinant f fragment, the protein was injected into the animal model. Immune response and the rise of specific antibodies titers were determined in immune sera. The results showed that immunization of mice with this recombinant protein could elicit significant serum IgG antibody up to 1/204800 titer. We show that the recombinant F protein was recognized by the mice sera immunized with the commercial vaccine. Moreover, the reactivity of vaccine strain virus with sera from F protein immunized mice suggested that the F protein is able to present similar epitopes with viral vaccine strain and hopefully could stimulate the immune system of the animal against the infectious viruses.
Volume 12, Issue 2 (6-2009)
Abstract
Objective: The Brucella melitensis virB operon, encoding a type IV secretion system (T4SS), is required for intracellular replication and persistent infection in the mouse model. The product of the second gene of the virB operon, virB2, is predicted to be localized at the bacterial surface, where they could potentially interact with host cells. Studies to date have focused on characterization of transposon mutations in this gene, which is expected to exert polar effects on downstream genes. We researched on the evaluation of relation between virB2 mutant with immunogenicity in mouse model and intracellular replication in macrophages J774.
Materials and Methods: In order to determine whether VirB2 is required for the function of the T4SS apparatus, we constructed and characterized deletion mutation of virB2 and kanamycin resistance gene replaced instead of virB2. For demonstration of intracellular replication, macrophages J774 and BALB/c mices were infected with wild type Brucella melitensis and mutated.
Results: After 48 h, number of mutated Brucella severe decreased severly compaired to wild type in macrophages J774, and Brucella with virB2 deletion decreased from 1×106 CFU/spleen less than 1000 CFU/spleen during 8 weeks, also total IgG increased in both but IL-12 and IFN-γ increased only in wild type.
Conclusion: VirB2 was essential for intracellular replication in mouse models and J774 macrophages. The virB2 mutant was unable to cause persistent infection in the mouse model, demonstrating the essential role of VirB2 in the function of the T4SS apparatus
Volume 12, Issue 4 (10-2010)
Abstract
Objective: 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.
Materials and Methods: 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.
Results: 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.
Conclusion: 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.
Volume 16, Issue 4 (2-2014)
Abstract
Objective: Acinetobacter baumannii (A. baumannii) is a major hospital pathogen with a high capacity to resist most common anti-microbial agents. A. baumannii is the etiologic agent for various illnesses including pneumonia, meningitis, and bloodstream infections. Biofilm associated proteins (Bap) are specific cell surface proteins essential for the formation of biofilm and play a main role in its pathogenicity. Previously, we have studied various regions of this protein. Considering different criteria, some regions were introduced as conserved and immunogenic. The immunogenicity of one of those regions pertaining to amino acids 706-1076 previously examined has shown that its expression triggers high antibody levels when injected to mice thereby protecting the animals against the bacterium. The present study examines region 4 of the Bap protein in order to validate the previous bioinformatics studies and its immunogenicity. Methods: In order to obtain immunity against this pathogen, a 1620 bp gene from Bap was amplified and cloned in pET32a. This region from Bap was cloned, expressed and verified by monoclonal antibodies. BALB/c mice were immunized by subcutaneous injection of the pure recombinant protein. Mice immune response was determined by ELISA. Results: High titer of raised antibodies implied that the recombinant protein was a strong antigen and immunogen. Conclusion: The results indicate that this protein can be a suitable choice for developing a new recombinant vaccine against A. baumannii.
Volume 22, Issue 3 (7-2019)
Abstract
Aims: Nef protein has been considered as an attractive target for the development of therapeutic HIV-1 vaccine. Furthermore, strong immunological properties of heat shock proteins (HSPs) led to their use as for subunit vaccine candidates. In the current study, the generation of Hsp20-Nef fusion protein was performed in E. , and in BALB/c mice.
Materials and Methods: At first, of Hsp20-Nef recombinant protein E. BL21 and Rosetta strains by SDS-PAGE and western blotting using anti-Nef monoclonal antibody. Then, the recombinant protein was purified by a reverse staining method. Finally, its potency was evaluated to elicit antibody response against HIV-1 Nef antigen using indirect ELISA in mice.
Findings: Our data showed a clear band of ~1230bp related to Hsp20-Nef fusion on agarose gel indicating the correct gene cloning in pET28a vector. The expression of Hsp20-Nef protein was confirmed as a clear band of ~47 SDS-PAGE and western blotting. In the immunological assay, the Hsp20-Nef protein and also the Nef protein emulsified with Freund’s adjuvant significantly enhanced the level of total compared to other groups. Moreover, of Hsp20-Nef was higher than Freund’s adjuvant/Nef in protein regimens (p<0.05).
Conclusion: The Hsp20-Nef fusion protein was effectively expressed in E. and significantly induced antibody response against HIV-1 Nef antigen.
