SRP® Technology » SRP® Vaccines

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.