Generation and characterization of high affinity humanized fab against hepatitis B surface antigen. Mol Biotechnol. 2009;43:29-40. [PMID: 19326261 DOI: 10.1007/s12033-009-9165-9]

Recent Progress on Neutralizing Antibodies against Hepatitis B Virus and its Implications

BACKGROUND

Hepatitis B virus (HBV) infection remains a global health problem. As "cure" for chronic hepatitis B is of current priority, hepatitis B immunoglobulin (HBIG) has been utilized for several decades to provide post-exposure prophylaxis. In recent years, a number of monoclonal antibodies (mAbs) targeting HBV have been developed and demonstrated with high affinity, specificity, and neutralizing potency.

OBJECTIVE

HBV neutralizing antibodies may play a potentially significant role in the search for an HBV cure. In this review, we will summarize the recent progress in developing HBV-neutralizing antibodies, describing their characteristics and potential clinical applications.

RESULTS AND CONCLUSION

HBV neutralizing antibodies could be a promising alternative in the prevention and treatment of HBV infection. More importantly, global collaboration and coordinated approaches are thus needed to facilitate the development of novel therapies for HBV infection.

A repertoire of high-affinity monoclonal antibodies specific to S. typhi: as potential candidate for improved typhoid diagnostic

Typhoid fever is a significant global health problem with highest burden on the developing world. The severity of typhoid is often underestimated, and currently available serological diagnostic assays are inadequate due to lack in requisite sensitivity and specificity. This underlines an absolute need to develop a reliable and accurate diagnostics that would benefit long-term disease control and treatment and to understand the real disease burden. Here, we have utilized flagellin protein of S. typhi that is surface accessible, abundantly expressed, and highly immunogenic, for developing immunodiagnostic tests. Flagellin monomers are composed of conserved amino-terminal and carboxy-terminal, and serovar-specific middle region. We have generated a panel of murine monoclonal antibodies (mAbs) against the middle region of flagellin, purified from large culture of S. typhi to ensure its native conformation. These mAbs showed unique specificity and very high affinity toward S. typhi flagellin without showing any cross-reactivity with other serovars. Genetic analysis of mAbs also revealed high frequency of somatic mutation due to antigenic selection process across variable region to achieve high binding affinity. These antibodies also displayed stable binding in stringent reaction conditions for antigen-antibody interactions, like DMSO, urea, KSCN, guanidinium HCl, and extremes of pH. One of the mAbs potentially reversed the TLR5-mediated immune response, in vitro by inhibiting TLR5-flagellin interaction. In our study, binding of these mAbs to flagellin, with high affinity, present on bacterial surface, as well as in soluble form, validates their potential use in developing improved diagnostics with significantly higher sensitivity and specificity.

Phage display creates innovative applications to combat hepatitis B virus

Hepatitis B virus (HBV) has killed countless lives in human history. The invention of HBV vaccines in the 20^th century has reduced significantly the rate of the viral infection. However, currently there is no effective treatment for chronic HBV carriers. Newly emerging vaccine escape mutants and drug resistant strains have complicated the viral eradication program. The entire world is now facing a new threat of HBV and human immunodeficiency virus co-infection. Could phage display provide solutions to these life-threatening problems? This article reviews critically and comprehensively the innovative and potential applications of phage display in the development of vaccines, therapeutic agents, diagnostic reagents, as well as gene and drug delivery systems to combat HBV. The application of phage display in epitope mapping of HBV antigens is also discussed in detail. Although this review mainly focuses on HBV, the innovative applications of phage display could also be extended to other infectious diseases.