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.

Scientists at Epitopix 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.

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.