The Application Of Filamentous Phage In The Treatment Of Melanoma And The Prevention Of Candida Albicans Infection

Filamentous phage is a kind of a human-safe filament virus nanofiber specifically infecting bacteria(～900 nm long and 6-7 nm wide).Phage display is a common technology with which the gene of foreign peptide can be inserted into the genome of the phage;the foreign peptide can be then fused and expressed on the outside wall of the phage.Thousands of recombinant phages displayed with different peptides can form a phage display library,from which the specific targeted peptide can be selected with the aim molecular.Phage can be useful in several fields because of the specificity of the peptide displayed on the phage to the aim molecular,for example: screening for the targeted site,as a vector of the antigen,imaging in vivo,studying the interaction between moleculars,and so on.In the field of screening for the targeted site,the tumor cells specific peptide selected from the phage display library was conjugated with the anti-tumor medicine to form complex,the complex would target and cure the tumor.In this study,With the technology of phage library screening,we selected two melanoma specific peptides from the M13 phage display library,the peptides were conjugated with 808 nm Near-infrared light sensitive gold nanorods to form targeted complex,the complex can transform the light to local high temperature which can leads to the cancer cells death.The results showed that the complex combined with peptide and gold nanorods can kill the melanoma cells in vitro under the 808 nm laser and slow down the melanoma tumor growth in vivo after administered with 808 nm laser.Phage is also an excellent vector because of its brilliant immunogenicity in vivo.The second part of this paper was conducted with a hybrid phage which was displayed with an epitope peptide of Sap2(EPS,with a sequence of Val-Lys-Tyr-Thr-Ser)on its side wall and thus serve as a vaccine for preventing Candida albicans(CA)infection.Candidiasis is a clinical intractable issue.CA can be probably a kind of pathogenic fungi in the patients who have a poor immunity such as cancer patients.It will be a big problem once it invaded the deeper organ in patients.In the second part of this paper,the engineered virus nanofibers and recombinant Sap2(r Sap2)are then separately used to immunize mice.The humoral and cellular immune responses in the immunized mice are evaluated.Surprisingly,the virus nanofibers significantly induce mice to produce strong immune response as r Sap2 and generate antibodies that can bind Sap2 and CA to inhibit the CA infection.Consequently,immunization with the virus nanofibers in mice dramatically increased the survival rate of CA-infected mice.As virus nanofibers,phages can not only act as effective antigen vector,but also are cost-effective by infecting bacteria to mass-produce.All these results suggest that hybrid phage nanofibers displaying EPS can be a vaccine candidate against fungal infection.In conclusion,phage is not only a vehicle used for searching the specific peptide of melanoma through a process called biopanning,consequently aimed to targeted cancer therapy;but also an excellent vector which can used to be a vaccine candidate against fungal infection.