innovation in motion

SRP® Technology

Vaxxinova proudly brings you SRP® Technology – a better way to make vaccines. SRP is unique because it works by starving bacteria of iron, an essential element for bacterial health.  SRP technology was discovered and developed in our laboratories, and we are the only manufacturer of this technology.

lab technician assistant analyzing a blood sample in test tube at laboratory with microscope. Medical, pharmaceutical and scientific research and development concept.

Microbiological Principle​

Pathogenic (disease-causing) bacteria require iron for growth and survival. But iron is also essential to animal hosts, which lock away iron using high-affinity soluble proteins such as heme and transferrin. Therefore, in order for bacteria to successfully invade and infect a host, they must utilize their own special iron-gathering protein systems to compete with the host for iron.

Specialized transport proteins called Siderophore Receptors (siderophore is Greek for iron carrier) are located on the outer surface of bacteria. Siderophore receptors belong to a class of tube-shaped proteins called Porins, which transport nutrients through the bacterial cell wall. Together, Siderophore Receptors and Porins (SRP®) can be extracted from bacteria to form a purified protein vaccine.

The 3-D structure of siderophore receptors can be visualized using the RCSB Protein Data Bank website. Pictured here (see link) is the ferric hydroxamate uptake receptor (FhuA) from E. coli, in complex with the much smaller siderophore protein, ferrichrome.

Test tubes closeup, science laboratory research and development concept

What is an SRP® Vaccine?

Siderophore Receptor and Porin proteins are the basis of all vaccines made using our patented SRP® Technology. It has long been recognized that SRP proteins are highly conserved; in other words, many various bacterial species carry these identical proteins, even though the rest of their exterior structures (LPS, which determines serotype) are unique. This feature makes SRP proteins an attractive target for vaccine development, which has been recognized in scientific literature for many years.

Our scientists discovered an extraction technique to harvest SRP proteins from commercial scale bacterial fermentations. This made it possible to purify SRP in quantities sufficient for economic vaccine production. Purified SRP can be formulated with many common vaccine adjuvants for administration into a host population by injection.

Bacteria macro photographed media in petri dishes in the laboratory

Active Immunization Using SRP Antigens

There are a number of essential features regarding these specialized transport proteins that open a window of opportunity for disease prevention through active immunization.

These specialized transport proteins are exposed on the outer membrane of the bacterium, making them susceptible to circulating antibodies produced by the host.

Biochemical and genetic analysis has shown these outer membrane proteins (OMPs) to be highly conserved and expressed in high copy number; e.g., OmpA, OmpC and OmpF are present at 100,000 copies per bacterial cell.

Active immunization against SRP proteins results in disabling bacterial cell wall receptors required for acquisition of elemental iron, which is an essential bacterial nutrient for metabolism and survival in host animal tissues.

Antibody mediated response to these surface exposed outer membrane proteins can increase opsonization, that is, increase macrophage activity resulting in increased phagocytosis and induce complement mediated bacterial lysis.

A number of these porins demonstrate immuno-regulatory activity, acting as T and/or B cell activators which stimulate the synthesis of various cytokines or activate intracellular signaling pathways, thus enhancing the protective efficacy of the vaccine composition.

Our Intellectual Property

Vaxxinova US has a family of patents protecting SRP® Technology as well as many other discoveries. This patent portfolio consists of more than 150 granted patents in the U.S., Europe and other countries, a score of pending patent applications and numerous patent drafts. Most major geographic markets of significance to animal health have been protected. We expect this proprietary base to grow and strengthen the technology thus lengthening the exclusivity period of product protection.

-45 US patents with numerous pending applications

-Over 120 international patents with numerous pending applications