Browsing by Subject "homologinen rekombinaatio"

Cancer afflicts an ever-growing number of people globally each year. In part due to a complex pathophysiology where much is still unknown, the need for new cancer treatments has been persistent, fuelled further by the issue of treatment resistance. An emerging field holding much promise in oncology is immunotherapy, a subgroup of which is oncolytic virus treatments. These treatments utilize the inherent or acquired ability of certain viruses to selectively replicate in tumor cells to fight cancer. One of these viruses is the adenovirus. With these viruses it is possible to modulate the immune response e.g. through the expression of certain genes. The thesis focuses on genetically arming an oncolytic adenovirus in an effort to enhance treatment efficacy. The transgene of choice is the CD40 ligand (CD40L), a costimulatory molecule capable of aiding in the development of systemic antitumor immunity. Adenoviruses have previously been designed expressing the CD40L, however, a novel aspect was introduced with the design and incorporation of a soluble a form of the protein. The main aim of the study was the construction of four functional oncolytic adenoviruses, encoded with either the human or mouse variants of the two CD40L proteins (full-length and soluble). Successful completion required protocols for the cloning, bacterial colony screening, and primary virus production to be established. Insertion of the CD40L transgenes into the E3-gp19k region of the chosen Ad5Δ24 backbone was first attempted with the traditional approach of homologous recombination. The method that ultimately proved successful was a one-step Gibson Assembly® reaction. Screening the bacterial colonies with colony polymerase chain reaction, the potential CD40L positive clones underwent restriction analysis to affirm the presence of the transgene in the viral genome, as well as the retainment of critical elements. Two out of three recombined plasmids carrying the full-length CD40L proceeded to transfection and virus propagation in A549 cells, after which the presence of the adenovirus and CD40L expression was confirmed with immunostaining. Finally, a protocol was successfully established by the construction of one of the intended four viruses. The protocol entails all the main steps from cloning until primary virus production, additionally offering the option of applying it to the genetic arming of the Ad5Δ24 with other transgenes of interest. In terms of future perspectives for the project, following construction of the remaining viruses, the intentions are to validate transgene expression and functionality for all constructs, as well as compare the immunogenicity between the full-length and soluble CD40L. In the event of promising results, the project will hopefully proceed to in vivo studies.