Table 5.
The genetic engineering Brucella vaccines.
| Genetic engineering vaccines | Significance | References |
|---|---|---|
| Deletion of the B. abortus 2,308 norD and high-affinity zinc uptake system (znuA) genes | Enhanced T cells and pro-inflammatory cytokines, compared to traditional RB51 vaccinated groups. | (176) |
| Deleting the phosphoglucomutase (pgm) gene of B. abortus 2,308 | Produced a recombinant strain with no serodiagnostic interference and protective Th1 immune responses compared to the S19 strain. | (177) |
| Deletion of GntR, a transcriptional regulator of many virulent antigens in B. abortus 2,308 | Resulted in an attenuated mutant with high protection levels in mice against the parental B. abortus 2,308 challenge | (178) |
| Deletion of the NodV and NodW genes in B. abortus 2,308 | Lowered survival in cell lines and a mouse model, as such it does not affect serological diagnosis. | (179) |
| Deleted znuA and purE genes in B. abortus 2,308 | Resulted in a live-attenuated mutant that required two doses to generate appropriate immune responses in mice. | (180) |
| Deleting the cgs gene in B. abortus S19 | Increased attenuation of S19 strain without altering its protective efficacy against B. abortus 2,308 | (181) |
| Deletion of the vjbR gene in B. abortus S19 | Resulted in a recombinant mutant with higher levels of protection, reduced inflammation, and safety than S19. | (182) |
| Deletion of the membrane fusogenic protein (Mfp) or OMP19 genes | Lowered Brucella persistence in animal studies. However, challenge tests have revealed that traditional attenuated vaccines such as S19 and RB51 strains provide similar levels of protection | (183) |
| Deletion of the wbkC gene of B. abortus (ΔwbkC) which translated to formyltransferase enzyme | Showed a protection level similar to B. abortus rough strain RB51 avoiding the rifampicin resistance which is the main disadvantage of RB51. However, B. abortus ΔwbkC did not produce the same level of protection when compared to B. abortus smooth strain S19, and avoiding interfering with the serological diagnosis which is also the main disadvantage of the S19 vaccine strain | (184) |
| Glycosyltransferase Wad C gene deletion in B. abortus S19 | Produced a better immune response comparable to those provided by the S19 strain | (186) |
| Single and double deletions of CydC cydD and CydC purD genes in B. abortus RB51 | Produced substantial attenuated mutants in cell lines. Additionally, compared to the RB51 strain, mice examination showed a Th1-type immune response and strong protective efficiency against B. abortus 2,308 strain infection | (145) (187) |
| Double deletion of CydC cydD and CydC purD genes in a field isolate of B. abortus biovar 1 (BA15) | Produced similar protective effects without the need for a subsequent booster shot | (188) |
| Deletion of the ATP/GDP-binding protein motif A (p-loop) and the ATP-binding/permease protein (cyd C) in B. abortus biovar 1 strain IVKB 9007 | Resulted in effective attenuated mutants that were unable to replicate intracellularly in a cell line model | (189) |
| Single and double deletions of wzm/wzt using the attenuated strain Brucella melitensis Rev1 | It has minimal serological interference asd it is not causing abortion in pregnant ewes. | (191) |