Vaccines for Rickettsia prowazekii
Recovery from a rickettsial infection confers very strong long-lasting protective immunity against subsequent reinfection. Therefore, it is very possible to develop a vaccine against a rickettsial disease which is very helpful in the prevention and control of diseases.
Rickettsia prowazekii
Rickettsia prowazekii (R. prowazekii), an obligate intracellular Gram-negative bacterium, is the etiologic agent of epidemic typhus. This disease is usually spread by rubbing the infected body louse or its feces into the skin abrasions. Infection can also occur by inhalation or mucosal inoculation of the aerosol form of the bacteria. R. prowazekii can remain infectious for several months in dried louse feces and antibiotic-resistant strains have been developed in the laboratory. Consequently, R. Prowazekii can be easily used as a biological weapon and is listed as a B selection agent by the Centers for Disease Control and Prevention (CDC) of the United States. Therefore, it is imperative to investigate virulence factors by proteomics as well as other approaches.
Vaccines for Rickettsia prowazekii
The attenuated Madrid E (E) strain of R. prowazekii, which had been demonstrated as an effective vaccine, is a spontaneous laboratory variant that was originally isolated from a typhus patient in Madrid in 1941 and quickly passaged 255 times in succession in embryonated eggs. Although the attenuated Madrid E strain has been used as a live vaccine and proved to provide good protection, it is unfortunate that it also shows the possibility of restoring virulence. The protective effect provided by the E strain of Madrid suggests that an irreversible, avirulent strain of R. prowazekii will be a safe and effective vaccine against this lethal infectious pathogen. By analyzing gene sequence differences or gene activities between avirulent and virulent strains, several genes are found to be associated with virulence. One of them is the R. prowazekii pld (Rp819) gene, which encodes a protein homologous to the phospholipase D (PLD) protein family. This protein exhibits PLD activity and has a conserved secretion signal, indicating that the encoded protein can be exposed at the host-pathogen interface. PLD plays an important role in the growth of rickettsia cells, so this protein is identified as a possible virulence factor for R. prowazekii.
The role of mutation or knockout of the pld gene in rickettsia cell growth and virulence is assessed. The pld mutant exhibits attenuated virulence in the guinea pig model and protect the animal from attack by subsequent virulent strains. Therefore, the transformant has potential as an irreversible attenuated vaccine strain and provides a new tool for understanding rickettsial biology and furthering advances in the prevention of epidemic typhus. In addition to the PLD gene, other virulence-related genes have gradually been discovered, and their mutations or deletions have an important influence on the virulence of the strain and are expected to be candidates for vaccine strains.
Our Services for Rickettsia prowazekii Vaccines
- Analysis of gene sequences
- Mutation or knockout of virulence gene
- Animal experiments and effect evaluation
- Analysis and processing of result data
Creative Biolabs has a team of professionals, each of them strictly controls every step of the way from program design to final data analysis, and strives to provide the first-class service to customers around the world. If you have any needs, please do not hesitate to contact us.
All of our products can only be used for research purposes. These vaccine ingredients CANNOT be used directly on humans or animals.
