Novel Protein for Development of a Chlamydial Vaccine

BIO 2007 Innovation Corridor “Best Poster” Award

The poster presented by Anna Z. Amar, Technology Development Associate, National Institute of Allergy and Infectious Diseases (NIAID), NIH – for a Novel Protein for Development of a Chlamydial Vaccine – was awarded “Best Poster” at the BIO 2007 Convention. 

The technology developed by Harlan D. Caldwell, Ph.D, Chief and Senior Investigator of the Laboratory of Intracellular Parasites, Rocky Mountain Laboratory, NIAID, relates to a novel chlamydial protein, termed polymorphic membrane protein D (PmpD) that can be used to develop a vaccine against all chlamydial serovariants that cause important human diseases, including sexually transmitted infection (STI) and blinding trachoma. The antigenically common PmpD is a target of protective neutralizing antibodies and, therefore, could be developed and used as a single univalent vaccine to prevent both chlamydial STI and trachoma. 

Chlamydia trachomatis isolates consist of 15 different serovariants that cause STI and blinding trachoma. Chlamydia is the leading cause of bacterial STI with an estimated 10 million new cases per year in the US alone. Infection of females can result in tubal factor infertility. Trachoma is the leading cause of preventable blindness in the developing world with an estimated 200 million individuals being afflicted by the disease. Trachoma has recently been identified as one of the world’s most important neglected infectious diseases. Control of both STI and trachoma by antibiotic intervention is not effective. Hence there is an urgent need for a safe and effective vaccine against both chlamydial STI and trachoma. Polymorphic membrane protein D is a novel chlamydial pan-neutralizing antigen that is the only known common neutralizing target shared by all human chlamydial isolates. These unique biological and antigenic properties make PmpD a highly valued target for the generation of a univalent vaccine that potentially could protect against all chlamydial serovariants that cause both STI and blinding trachoma. 

The market value of a vaccine capable of preventing chlamydial STI is expected to be $3-5 billion per year. This could rise to $10 billion or more by the year 2010 as the only current treatment, antibiotic intervention, is negatively affecting natural immunity, thereby leading to an anticipated increase in the prevalence of chlamydial STI. 

Currently there is no vaccine for the prevention of human chlamydial diseases. This technology represents the first antigen that could be developed as a univalent recombinant protein, DNA or infectious vectored vaccine capable of protecting against all human chlamydial serovariants.