Steven G. Reed

Characterization of KLK4 expression and detection of KLK4-specific antibody in prostate cancer patient sera.

The ability to identify prostate tumor or prostate tissue specific genes that are expressed at high levels and use their protein products as targets could greatly aid in the diagnosis and treatment of prostate cancer. Using a polymerase chain reaction (PCR)-based subtraction technique, we have recovered the recently described KLK4 (prostase) gene from human prostate cDNA. In this study, KLK4 gene expression in human prostate tumors was further characterized using cDNA quantitative PCR and immunohistochemistry, demonstrating that the gene is specifically expressed at both the mRNA and protein levels in normal human prostate tissue, and in both primary and metastatic prostate tumor samples. Quantitative mRNA analysis also demonstrated low level expression including adrenal gland, salivary gland and thyroid. Finally, it was demonstrated that prostate cancer patient sera contain antibodies that bind specifically to recombinant KLK4 protein. This antibody has been used to detect KLK4-specific peptides in epitope mapping experiments. The relatively specific expression profile and elevated level of KLK4 mRNA and protein in both tumor and normal prostate tissues, in addition to detectable KLK4-specific antibody in cancer patient sera, supports additional efforts to determine if KLK4 can play a role in the diagnosis of prostate cancer, the monitoring of residual disease, or act as a target for immunotherapy.

A combination of TLR-4 agonist and saponin adjuvants increases antibody diversity and protective efficacy of a recombinant West Nile Virus antigen

Members of the Flaviviridae family are the leading causes of mosquito-borne viral disease worldwide. While dengue virus is the most prevalent, the recent Zika virus outbreak in the Americas triggered a WHO public health emergency, and yellow fever and West Nile viruses (WNV) continue to cause regional epidemics. Given the sporadic nature of flaviviral epidemics both temporally and geographically, there is an urgent need for vaccines that can rapidly provide effective immunity. Protection from flaviviral infection is correlated with antibodies to the viral envelope (E) protein, which encodes receptor binding and fusion functions. TLR agonist adjuvants represent a promising tool to enhance the protective capacity of flavivirus vaccines through dose and dosage reduction and broadening of antiviral antibody responses. This study investigates the ability to improve the immunogenicity and protective capacity of a promising clinical-stage WNV recombinant E-protein vaccine (WN-80E) using a novel combination adjuvant, which contains a potent TLR-4 agonist and the saponin QS21 in a liposomal formulation (SLA-LSQ). Here, we show that, in combination with WN-80E, optimized SLA-LSQ is capable of inducing long-lasting immune responses in preclinical models that provide sterilizing protection from WNV challenge, reducing viral titers following WNV challenge to undetectable levels in Syrian hamsters. We have investigated potential mechanisms of action by examining the antibody repertoire generated post-immunization. SLA-LSQ induced a more diverse antibody response to WNV recombinant E-protein antigen than less protective adjuvants. Collectively, these studies identify an adjuvant formulation that enhances the protective capacity of recombinant flavivirus vaccines.West Nile Virus: adjuvant combinations boost vaccine efficacyThere is currently no approved human vaccine for West Nile Virus (WNV); however, it is known that protective immune responses are generally directed to the viral E protein. Neal Van Hoeven and colleagues at the Infectious Disease Research Institute in Seattle use recombinant WNV E-protein antigen adjuvanted with different combinations of a synthetic Toll-like receptor 4 agonist (SLA) and the saponin QS21 to determine optimal vaccination strategies in preclinical mouse and hamster models. SLA plus QS21 synergize in the production of neutralizing antibodies and when used together generate higher antibody diversity—a property that directly correlates with their protective capacity in vivo. Uniquely, the combination of QS21 plus SLA was also able to elicit robust T helper 1 responses. These findings highlight a promising adjuvant combination that might form the basis of an effective human WNV vaccine.

Vaccines Against Mycobacterium tuberculosis: An Overview from Preclinical Animal Studies to the Clinic

More than a decade ago the World Health Organization (WHO) declared tuberculosis (TB) a global emergency and called on the biomedical community to strengthen its efforts to combat this scourge. The WHO predicts that by 2020 almost one billion people will be infected, with 35 million dying from the disease if research for new approaches to the management of this disease is unsuccessful (1). Designing a better TB vaccine is a high priority research goal. This chapter will review the various strategies currently being used to prevent and treat TB. In spite of the numerous new vaccine candidates in clinical trials, and several others in the preclinical pipeline, no clear TB vaccine development strategy has emerged.