alexa AroD deletion attenuates Shigella flexneri strain 2457T and makes it a safe and efficacious oral vaccine in monkeys.


Journal of Vaccines & Vaccination

Author(s): Krnell A, Cam PD, Verma N, Lindberg AA

Abstract Share this page

The aromatic-dependent live Shigella flexneri 2a vaccine strain SFL1070, with a deleted aroD gene, had a much reduced intracellular growth in HeLa cells compared with its parent strain S. flexneri 2457T. S. flexneri SFL1070 gave no adverse effects in eight Macaca fascicularis monkeys orally vaccinated with four doses of 1 x 10(11) live bacteria within a 5-week period, whereas S. flexneri 2457T caused dysentery in all eight non-vaccinated monkeys. Thus the aromatic dependency rendered S. flexneri SFL1070 significantly attenuated (p = 0.00008). Significant intestinal S. flexneri lipopolysaccharide (LPS)-specific sIgA responses were seen in seven of eight vaccinated monkeys (p < 0.01) after four doses with SFL1070. However, serum IgG or IgA responses to various S. flexneri LPS antigens and the invasion plasmid antigens (Ipa-s) were seen in only four of eight vaccinated monkeys. The serum IgG titre increases against S. flexneri Y and 2a LPS reached significant levels (p < or = 0.05). All but one of the vaccinated monkeys were protected against oral challenge with 1 x 10(10) or 1 x 10(11) live S. flexneri 2457T given 2 weeks after the last vaccination. The protection was highly significant (p = 0.0007) as all non-vaccinated monkeys challenged with equal doses of strain 2457T developed dysentery. Three of them succumbed. Challenge infection of vaccinated monkeys elicited serum IgA and IgG responses to the homologous S. flexneri 2a LPS in three monkeys each (0.005 < or = p < or = 0.025). Serum IgA and IgG responses to the Ipa-s were seen in five and four monkeys each (0.01 < p < or = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)


  • To read the full article Visit
  • Open Access
This article was published in Vaccine. and referenced in Journal of Vaccines & Vaccination

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

Peer Reviewed Journals
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version