• Vaccine Name: S. flexneri 2a LPS vaccine complexed with N. meningitidis proteosomes
• Target Pathogen: Shigella
• Target Disease: Shigellosis
• 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).

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).

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).