• Vaccine Ontology ID: VO_0000674
• Type: Recombinant vector vaccine
• Preparation: S. flexneri SFL124-27 is a spontaneous rough mutant of the attenuated S. flexneri auxotrophic strain SFL124, which carries a deletion of the aroD gene. A recombinant strain SFL124-27 that expresses S. dysenteriae 1 O antigen was selected as the vaccine candidate (Klee et al., 1997).
• Virulence: The vaccine was demonstrated to be immunogenic in animal models, leading to 47% full protection and 53% partial protection against challenge with the wild-type strain (Klee et al., 1997).

• Vaccine Ontology ID: VO_0011466
• Type: Subunit vaccine
• Status: Research
• Antigen: IpaB, IpaC, and IpaD, and LPS (Turbyfill et al., 2000).
• ipaB gene engineering:
  • Type: Recombinant protein preparation
  • Detailed Gene Information: Click Here.
• IpaC gene engineering:
  • Type: Recombinant protein preparation
  • Detailed Gene Information: Click Here.
• ipaD gene engineering:
  • Type: Recombinant protein preparation
  • Detailed Gene Information: Click Here.
• Preparation: A novel method has been developed for isolating a macromolecular complex containing the major known virulence factors and immunogens from intact, viable, virulent shigellae. This structure was referred as the invasin complex, or invaplex. It has been possible to isolate two forms of the invaplex, called invaplex 24 and invaplex 50, by FPLC ion-exchange chromatography from S. flexneri 2a and S. flexneri 5. Both forms contain the invasins (IpaB, IpaC, and IpaD) and LPS, but IpaA and VirG, a truncated form of VirG, were found only in Invaplex 50. Other unidentified proteins were also present in both invaplex preparations (Turbyfill et al., 2000).
• Immunization Route: Intranasally
• Description: Isolated invasin complex (invaplex), which contains the major antigens of virulent Shigella, is shown to be immunogenic when delivered by a mucosal route without the need for any additional adjuvant. Western blot analysis of the complex indicates that all of the major virulence antigens of Shigella, including IpaB, IpaC, and IpaD, and LPS are components of this macromolecular complex. (Turbyfill et al., 2000)

• Vaccine Ontology ID: VO_0000682
• Type: Subunit vaccine
• Antigen: The antigen for this acellular vaccine is purified Shigella flexneri LPS (Orr et al., 1993).
• Preparation: Purified shigella LPS and group C serotype 2b N. meningitidis outer membrane proteins were mixed at a 1:1 ratio in PBS containing 1% Empigen. The mixture was dialyzed across a dialysis membrane against PBS. Samples of the purified LPS were mixed with PBS and sodium bicarbonate (Orr et al., 1993).
• Virulence: Strong anamnestic responses were found , so acellular Shigella vaccines can protect against Shigella infection (Orr et al., 1993).

• Vaccine Ontology ID: VO_0011468
• Type: Subunit vaccine
• Status: Research
• Antigen: IpaB, IpaC, and IpaD, and LPS (Turbyfill et al., 2000).
• ipaB gene engineering:
  • Type: Recombinant protein preparation
  • Detailed Gene Information: Click Here.
• IpaC gene engineering:
  • Type: Recombinant protein preparation
  • Detailed Gene Information: Click Here.
• ipaD gene engineering:
  • Type: Recombinant protein preparation
  • Detailed Gene Information: Click Here.
• Preparation: A novel method has been developed for isolating a macromolecular complex containing the major known virulence factors and immunogens from intact, viable, virulent shigellae. This structure was referred as the invasin complex, or invaplex. It has been possible to isolate two forms of the invaplex, called invaplex 24 and invaplex 50, by FPLC ion-exchange chromatography from S. flexneri 2a and S. flexneri 5. Both forms contain the invasins (IpaB, IpaC, and IpaD) and LPS, but IpaA and VirG, a truncated form of VirG, were found only in Invaplex 50. Other unidentified proteins were also present in both invaplex preparations (Turbyfill et al., 2000).
• Immunization Route: Intranasally
• Description: Isolated invasin complex (invaplex), which contains the major antigens of virulent Shigella, is shown to be immunogenic when delivered by a mucosal route without the need for any additional adjuvant. Western blot analysis of the complex indicates that all of the major virulence antigens of Shigella, including IpaB, IpaC, and IpaD, and LPS are components of this macromolecular complex.

• Vaccine Ontology ID: VO_0000739
• Type: Live, attenuated vaccine
• Antigen: The protective antigen for this vaccine is O-antigen from S. flexneri 2a (Shim et al., 2007).
• Preparation: Virulent S. flexneri 2a 2457T strains were incubated, then cultured. The cells were then subjected to a high-pressure homogenizer to break down the bacterial ribosome. The ribosome was then purfied. The O-antigen concentration accounted for approximately 5% of the preparation. This vaccine is composed of O-antigen and ribosome isolated from S. flexneri 2a (Shim et al., 2007).
• Virulence: SRV is immunogenic and provides protective efficacy in mice (Shim et al., 2007).

• Vaccine Ontology ID: VO_0004703
• Type: Recombinant vector vaccine
• Status: Research
• Host Species for Licensed Use: Baboon
• Preparation: A tandemly-linked rfb-rfp gene cassette was cloned into low copy plasmid pGB2 to create pSd1 (Xu et al., 2007).
• Immunization Route: Intramuscular injection (i.m.)

• Vaccine Ontology ID: VO_0004701
• Type: Recombinant vector vaccine
• Status: Research
• Host Species for Licensed Use: Baboon
• Preparation: Ty21a-Ss simultaneously expresses both homologous Ty21a and heterologous S. sonnei O-antigens (Dharmasena et al., 2013).
• Immunization Route: Intramuscular injection (i.m.)

Mouse Response

• Host Strain: BALB/c
• Vaccination Protocol: To assess whether the recombinant O antigen was immunogenic and to compare the immunogenicity with that of wild-type S. dysenteriae 1, groups of five six-week-old female BALB/c mice were immunized on days 0, 14, and 28 by intraperitoneal injection of 0.2 x 10^8 to 1.0 x 10^8 heat-killed bacteria suspended in PBS. Two weeks after the last immunization, the mice were sacrificed, blood samples were collected, and antibody titers against LPS of S. dysenteriae 1 were determined by enzyme-linked immunosorbent assay (Klee et al., 1997).
• Persistence: The antibody titers of mice immunized with S. dysenteriae 1 or S. flexneri SFL124-27::Tn(rfp-rfb)-39 were significantly higher than the titers in the nonimmunized group and in mice immunized with the rough strain SFL124-27. This indicates the synthesis of enough surface-displayed LPS molecules to trigger a specific immune response, a prerequisite for a vaccine strain (Klee et al., 1997).
• Challenge Protocol: No challenge was done on the mice, as this was only to assess the immunogenicity of the recombinant O antigen.

Mouse Response

• Host Strain: BALB/cByJ
• Vaccination Protocol: The ability of the invaplex fractions to promote an immune response in BALB/cByJ mice was tested in groups of five mice. Each mouse was immunized intranasally with 5 μg of invaplex 24 or invaplex 50 from S. flexneri 2a or S. flexneri 5 on days 0, 14, and 28. Saline was used to immunize control animals. A total antigen volume of 25 μl was delivered in 5 to 6 small drops applied to the external nares with a micropipette (Turbyfill et al., 2000).
• Challenge Protocol: Three weeks after the final immunization with either S. flexneri 2a invaplex 24, invaplex 50, or saline, mice (15 per group) were challenged intranasally with a lethal dose of S. flexneri 2a 2457T (10^7 CFU/30 μl) as described for the mouse lung model. The mouse challenge dose was prepared from a frozen lot of S. flexneri 2a that had been harvested during the log phase of growth, which is the time of optimal invasiveness for shigellae, and then stored in liquid nitrogen (Turbyfill et al., 2000).
• Efficacy: A significant level of protection against lethal challenge was achieved in mice immunized with S. flexneri 2a invaplex 24. Invaplex-immunized mice lost weight upon challenge, but by days 3 to 4 they began to recover and gain weight whereas control mice soon died. Similar levels of protection were afforded by invaplex 24 (12 of 15 mice survived).

Mouse Response

• Host Strain: BALB/c
• Vaccination Protocol: BALB/c mice were were immunized either orally or intranasally with 100 miroliters of PBS containing 100 micrograms of LPS with 0.2 M sodium bicarbonate that was given either alone or complexed with 100 micrograms of proteosomesusing a bent metal tube. For intranasal immunization, 25 micrograms of LPS either alone or complexed with 10 micrograms of proteosomeswas slowly placed into one or both of the nares. The control group recieved diluent without antigen (Orr et al., 1993).
• Immune Response: Vaccination produced high levels of anti-LPS IgG and anti-LPS IgA in mice immunized two or three times (Orr et al., 1993).
• Challenge Protocol: Mice were challenged with LPS two weeks after their last immunization (Orr et al., 1993).
• Efficacy: All mice in control groups were infected. 14 out of 19 and 11 out of 16 mice were protected from severe infection after intranasal or oral vaccination. 9 out of 16 animals were protected from any illness (Orr et al., 1993).

Mouse Response

• Host Strain: BALB/cByJ
• Vaccination Protocol: The ability of the invaplex fractions to promote an immune response in BALB/cByJ mice was tested in groups of five mice. Each mouse was immunized intranasally with 5 μg of invaplex 24 or invaplex 50 from S. flexneri 2a or S. flexneri 5 on days 0, 14, and 28. Saline was used to immunize control animals. A total antigen volume of 25 μl was delivered in 5 to 6 small drops applied to the external nares with a micropipette (Turbyfill et al., 2000).
• Challenge Protocol: Three weeks after the final immunization with either S. flexneri 2a invaplex 24, invaplex 50, or saline, mice (15 per group) were challenged intranasally with a lethal dose of S. flexneri 2a 2457T (107 CFU/30 μl) as described for the mouse lung model (18). The mouse challenge dose was prepared from a frozen lot of S. flexneri 2a that had been harvested during the log phase of growth, which is the time of optimal invasiveness for shigellae, and then stored in liquid nitrogen (Turbyfill et al., 2000).
• Efficacy: A significant level of protection against lethal challenge was achieved in mice immunized with S. flexneri 2a invaplex 50. Invaplex-immunized mice lost weight upon challenge, but by days 3 to 4 they began to recover and gain weight whereas control mice soon died. Similar levels of protection were afforded by invaplex 50 (10 of 15 mice survived) (Turbyfill et al., 2000).

Mouse Response

• Host Strain: BALB/c
• Vaccination Protocol: Mice were subcutaneously or intranasally vaccinated on days 0 and 14 with a 2.5 microgram dose of the O-antigen. For a control, attenuated S. flexneri 2a SC602 strain (5 x 10^6 CFU) was administered (Shim et al., 2007).
• Immune Response: Both subcutaneous and intranasal vaccination induced high levels of Ag-specific IgG Ab in sera. Intranasal vaccination elicited robust levels of LPS-specific IgA Ab in the mucosal secretions. The heightened levels were identical to those produced by vaccination with the S. flexneri 2a SC602 strain (Shim et al., 2007).
• Challenge Protocol: One week after the second vaccination, the mice were challenged with virulent S. flexneri 2a (1 x 10^7 or 5 x 10^7 CFU) to induce pulmonary pneumonia (Shim et al., 2007).
• Efficacy: Groups of mice vaccinated intranasally with SRV demonstrated less severe pneumonia than those mice that received subcutaneous vaccines. SRV administration via the parenteral route did not effictively protect against the challenge. Almost 65% of mice that received the intranasal vaccine survived the two vaccine doses compared to about 20% of mice that received the subcutaneous dose. These data suggest that a higher degree of protective immunity is conferred against Shigella by SRV when it is administered by the intranasal route (Shim et al., 2007).

Mouse Response

• Vaccination Protocol: Groups of 10 mice were inoculated intraperitoneally with one or two 0.5 ml doses of either vaccine suspension or sterile PBS (Xu et al., 2007).
• Vaccine Immune Response Type: VO_0003057
• Challenge Protocol: Immunized and control mice were challenged 5 weeks after immunization with a lethal dose of 7.5 × 10^5 cfu of the freshly grown, mid-log phase virulent S. dysenteriae 1 stxA-deleted strain (1617Δ stxA) in 0.5 ml of 5% hog gastric mucin (Sigma) in sterile PBS (Xu et al., 2007).
• Efficacy: Animal immunization studies showed that Ty21a (pSd1) induces protective immunity against high stringency challenge with virulent S. dysenteriae 1 strain 1617 (Xu et al., 2007).

Mouse Response

• Vaccination Protocol: Mice were immunized with vaccine candidate strains (Ty21a-Ss) or negative controls Ty21a alone and PBS (Dharmasena et al., 2013).
• Vaccine Immune Response Type: VO_0003057
• Challenge Protocol: Immunized and control mice were challenged intraperitoneally, 2 weeks after final immunization, with ∼5 × 10^6 CFU/ml of freshly grown, mid-log-phase virulent S. sonnei strain 53GI in 0.25 ml (∼2 × 10^6 CFU per mouse) of 5% hog gastric mucin (Sigma) dissolved in sterile saline (i.e. approximately 100 times the 50% lethal infectious dose [LD50]) (Dharmasena et al., 2013).
• Efficacy: Ty21a-Ss elicited strong dual anti-LPS serum immune responses and 100% protection in mice against a virulent S. sonnei challenge (Dharmasena et al., 2013).

Guinea pig Response

• Host Strain: Dunkin Hartley
• Vaccination Protocol: The Sereny test with guinea pigs was performed as follows: Congo red-positive colonies of the Shigella vaccine candidate were diluted in PBS, and 25 ml was applied to the conjunctival sacs of 15 adult Dunkin Hartley guinea pigs at days 0, 7, 14, and 21 with an average of four immunizing doses, 3.7 x 10^9 bacteria per eye (Klee et al., 1997).
• Persistence: Vaccination led to statistically significant amounts of antibodies against S. Dysenteriae (Klee et al., 1997).
• Immune Response: None of the four immunization doses given to the 15 guinea pigs resulted in detectable keratoconjunctivitis, thereby demonstrating the safety of this prototype vaccine candidate in this animal model (Klee et al., 1997).
• Challenge Protocol: At day 35, the animals were challenged with 10^8 bacteria of the virulent strain S. dysenteriae 1 W30864 per eye, and the symptoms of keratoconjunctivitis were recorded for 6 days. As a control, another group of 14 nonvaccinated guinea pigs was also challenged with the virulent strain at day 35 (Klee et al., 1997).
• Efficacy: In the vaccinated group, 7 of 15 animals developed no signs of keratoconjunctivitis (47% full protection), and in the other 8 animals, later development of the disease was observed (53% partial protection), resulting in a combined protection of 100%, whereas in the nonvaccinated group 71% of challenged animals rapidly developed severe disease.The vaccinated animals developed symptoms of keratoconjunctivitis later than animals of the control group, and the absolute number of guinea pigs showing strong reactions, or purulent inflammation of the whole eye, was significantly reduced (Klee et al., 1997).

Guinea pig Response

• Host Strain: DH
• Vaccination Protocol: Anesthetized guinea pigs were immunized. Orally, they each received 200 microliters of PBS with sodium bicarbonate and 200 micrograms of the LPS complex. Intranasally, each guinea pig received 50 microliters of PBS with 40 micrograms of the LPS complex (Orr et al., 1993).
• Immune Response: Guinea pig titers proved strong anti-LPS IgG antibodies and anti-LPS IgA antibodies (Orr et al., 1993).
• Challenge Protocol: The conjunctival sac of one eye of each animal was inoculated with 30 microliters of a suspension containing and estimeted 10^8 of homologous bacteria (Orr et al., 1993).
• Efficacy: The vaccines elicited an in vivo protection against homologous bacteria (Orr et al., 1993).