VPREB3 has previously been identified as a useful diagnostic marker, however its precise biological function is still unknown. Previous research has attempted to propose a function however, due to a lack of phenotype in VpreB3-deficient mice (unpublished) and a lack of robust reagents, i.e. monoclonal antibodies recognising VPREB3, it is still unknown. Its intracellular localisation and restricted expression have made it difficult to produce large amounts of the protein to be used in the production of monoclonal antibodies. This project attempted to address the production of soluble protein by creating a vector expressing a potentially soluble VPREB3 accomplished by replacement of the protein’s signal peptide with that of VPREB1, coupled with a HaloTag. The study sought to express the modified VPREB3 coupled with the HaloTag, following different transfection approaches in HEK 293T cells, with the HaloTag acting as a proxy for expression. Fluorescent labelling using the R110Direct Ligand and fluorescent imaging of the cells detected the expression of the HaloTag, indicating HaloTag expression from the transfection vector. However, Sanger Sequencing revealed a lack of the modified sequence within the vector and as such a lack of VPREB3 expression. The analysis of the data from the images proved a significant difference in transfection efficiency between the Invitrogen-7.5 and Alternative-7 methods, at a p = 0.05 significance level. The findings in this study contribute to the methods required for establishing a secretory VPREB3 expression system, which can be used to facilitate production of monoclonal antibodies specific for the protein and thereby aid in identifying its function.