Phage T7 as a Potential Platform for Vaccine Development

2021 ◽  
pp. 75-93
Author(s):  
Chuan Loo Wong ◽  
Chean Yeah Yong ◽  
Khai Wooi Lee
Keyword(s):  
Vaccine Development ◽  
Phage T7

scholarly journals Reduced pathogenicity of velogenic NDV strain AF22420-I via site-directed mutagenesis of V gene

2021 ◽  
pp. 59-70
Author(s):  
Bei Ru Lee ◽  
Jeevanathan Kalyanasunandram ◽  
Kavitha Murulitharan ◽  
Kok Song Lai ◽  
Suet Lin Chia ◽  
...  
Keyword(s):  
Vaccine Development ◽  
Lethal Dose ◽  
Therapeutic Vaccine ◽  
Premature Stop Codon ◽  
Site Directed Mutagenesis ◽  
Silent Mutation ◽  
V Protein ◽  
P Gene ◽  
Anti Cancer ◽  
Phage T7

Newcastle disease virus (NDV), an avian paramyxovirus, has the potential to be used as an anti-cancer therapeutic vaccine due to its oncolytic and immunostimulatory activities. The virus can be categorised into three pathotypes: lentogenic, mesogenic, and velogenic; of the three pathotypes, the lentogenic strains such as the La Sota are the preferred pathotype for vaccine development due to their low virulence to birds. On the other hand, the translation of the virus to clinic of the velogenic strain AF2240-I is hindered by its virulence towards birds although it exhibits strong oncolysis with significant outcomes both in vitro and in vivo. This study aims to reduce the pathogenicity of AF2240-I yet retaining the anti-cancer properties of the virus. To achieve this, the V protein that acts as an interferon antagonist was chosen to be mutated. It is a non-structural protein that does not interfere with the binding and infection of the virus; hence, mutation of this virulence factor was deducted to be able to reduce harm to the avian species but retain its anti-cancer properties as much as possible. The V protein, which was produced from the insertion of an additional G into a conserved editing site of the P gene, was mutated by substituting the G nucleotide at position 411 from the start of P gene to a T nucleotide. This mutation will produce a premature stop codon from the V mRNA, resulting in a truncated V protein; but only causes a silent mutation in the P protein. The recombinant virus was recovered by the use of BHK cells stably expressing the phage T7 RNA polymerase. The pathogenicity of the mutated virus was determined in 9- to 11-day-old embryonated SPF chicken eggs. The mean death time (MDT) was determined to be 73.6 hours at the minimal lethal dose of 10-7, resembling to that of a mesogenic strain. The virulence of the mutated virus has been successfully reduced where it could be potentially used as the vector for the development of recombinant oncolytic virus for cancer treatment.

Electron Microscopy of Bacteriophage T7 Internal Head Proteins

1975 ◽  
Vol 33 ◽  
pp. 638-639
Author(s):  
P. Serwer
Keyword(s):  
Electron Microscopy ◽  
Bacteriophage T7 ◽  
Specimen Preparation ◽  
Dna Molecule ◽  
The Core ◽  
Internal Core ◽  
Phage T7 ◽  
T7 Phage ◽  
Preparation Techniques ◽  
Internal Head

The genome of bacteriophage T7 is a duplex DNA molecule packaged in a space whose volume has been measured to be 2.2 x the volume of the B form of T7 DNA. To help determine the mechanism for packaging this DNA, the configuration of proteins inside the phage head has been investigated by electron microscopy. A core which is roughly cylindrical in outline has been observed inside the head of phage T7 using three different specimen preparation techniques.When T7 phage are treated with glutaraldehyde, DNA is ejected from the head often revealing an internal core (dark arrows in Fig. 1). When both the core and tail are present in a particle, the core appears to be coaxial with the tail. Core-tail complexes sometimes dislodge from their normal location and appear attached to the outside of a phage head (light arrow in Fig. 1).

Drug and Vaccine Development and Access

2020 ◽  
Author(s):  
Micah Berman ◽  
Efthimios Parasidis ◽  
Patricia J. Zettler
Keyword(s):  
Vaccine Development

HIV-1 Accessory Proteins: Which one is Potentially Effective in Diagnosis and Vaccine Development?

2020 ◽  
Vol 28 ◽  
Author(s):  
Alireza Milani ◽  
Kazem Baesi ◽  
Elnaz Agi ◽  
Ghazal Marouf ◽  
Maryam Ahmadi ◽  
...  
Keyword(s):  
Immune Response ◽  
Vaccine Development ◽  
Treated Group ◽  
Vaccine Antigen ◽  
Accessory Proteins ◽  
Serological Method ◽  
Th2 Immune Response ◽  
Untreated Individuals ◽  
Immunogenic Properties ◽  
Hiv 1

Background:: The combination antiretroviral therapy (cART) could increase the number of circulating naive CD4 T lymphocytes, but was not able to eradicate human immunodeficiency virus-1 (HIV-1) infection. Objective:: Thus, induction of strong immune responses is important for control of HIV-1 infection. Furthermore, a simple and perfect serological method is required to detect virus in untreated-, treated- and drug resistant- HIV-1 infected individuals. Methods:: This study was conducted to assess and compare immunogenic properties of Nef, Vif, Vpr and Vpu accessory proteins as an antigen candidate in mice and their diagnostic importance in human as a biomarker. Results:: Our data showed that in mice, all heterologous prime/ boost regimens were more potent than homologous prime/ boost regimens in eliciting Th1 response and Granzyme B secretion as CTL activity. Moreover, the Nef, Vpu and Vif proteins could significantly increase Th1 immune response. In contrast, the Vpr protein could considerably induce Th2 immune response. On the other hand, among four accessory proteins, HIV-1 Vpu could significantly detect treated group from untreated group as a possible biomarker in human. Conclusion:: Generally, among accessory proteins, Nef, Vpu and Vif antigens were potentially more suitable vaccine antigen candidates than Vpr antigen. Human antibodies against all these proteins were higher in HIV-1 different groups than healthy group. Among them, Vpu was known as a potent antigen in diagnosis of treated from untreated individuals. The potency of accessory proteins as an antigen candidate in an animal model and a human cohort study are underway.

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