摘要：The presence of anti-p53 antibody in serum is a biomarker for cancer. However, its high sensitivity detection is still an issue in cancer diagnosis. To tackle this challenge, we used fd phage, a human-safe bacteria-specific virus nanofiber that can be mass-produced by infecting host bacteria in an error-free manner, and genetically engineered it to display a peptide capable of recognizing and capturing anti-p53 antibody on its side wall. We employed the resultant phage nanofibers as a capture probe to develop a modified version of the enzyme- linked immunosorbent assay （ELISA） method, termed phage-ELISA. We compared it to the traditional ELISA method for the detection of anti-p53 antibody, p53-ELISA, which uses recombinant wild-type p53 protein to capture anti-p53 antibody. We applied phage-ELISA to detect anti-p53 antibody in an experimental group of 316 patients with various types of malignant tumors. We found that a detection rate of 17.7% （56 positive cases） was achieved by phage-ELISA, which was comparable to the detection rate of 20.6% for p53-ELISA （65 positive cases）. However, when both phage and p53 were combined to form antibody-capturing probes for phage/p53-ELISA, a detection rate of 30.4% （96 positive cases） was achieved. Our work showed that owing to the combined capture of the anti-p53 antibody by both phage nanofibers and p53, the phage/p53-ELISA achieved the highest diagnostic accuracy and detection efficiency for the anti-p53 antibody in patients with various types of cancers. Our work suggests that a combination of nanofibers and antigens, both of which capture antibody, could lead to increased detection sensitivity, which is useful for applications in the life sciences, clinical medicine, and environmental sciences.

摘要：Candida albicans （C. albicans） infection has a high mortality rate in immunocompromised patients. Owing to the inefficiency of the current diagnostic system and the absence of licensed vaccines against candidiasis, the prevention of C. albicans infection remains a challenge. C. albicans infection can be evaluated and prevented by the anti-secreted aspartyl proteinase 2 antibody （anti-Sap2 IgG） and Hsp90 antibody （anti-Hsp90 IgG）. In this study, to explore a new agent for the improvement of the diagnosis and the prevention of C. albicans infection, an engineered fd bacteriophage, which is considered a human-safe virus nanofiber, was designed and prepared with two epitopes that could induce and capture anti-Sap2 IgG and anti-Hsp90 IgG. The dual-display phage was employed as a novel capture probe to develop a new enzyme-linked immunosorbent assay （ELISA） method, which significantly improved the detection rate compared with those of the ELISA in which recombinant protein Sap2 was used as coating antigen to capture the spedfic antibodies （rSap2-ELISA） and the ELISA in which recombinant protein Hsp90 was used as coating antigen to capture the specific antibodies （rHsp90-ELISA）. In addition, the nanofibers acted as a potential vaccine to immunize mice, as well as recombinant proteins, more efficiently mediated humoral and cellular immune responses, decreased levels of C. albicans colonization, and increased the survival rates in C. albicans-infected mice. Therefore, the phage dual-display nanofiber has been shown to be a powerful bifunctional agent for protection against and sensitive detection of clinical infections, which has the potential to be widely used in the life sciences, clinical medicine, and environmental sciences.