TY - JOUR
T1 - Safety and immunogenicity of the live oral auxotrophic Shigella flexneri SFL124 in volunteers
AU - Li, An
AU - Pál, Tibor
AU - Forsum, Urban
AU - Lindberg, Alf A.
N1 - Funding Information:
The authors are grateful to Dr Anders Kfirnell for valuable advice during the course of this investigation. This work was supported by the Swedish Medical Research Council (grant no. 16x-656), Stiftelsen Sigurd and Elsa Goljes Minne and the Swedish Agency for Research Cooperation_ with Developing Countries (SAREC).
PY - 1992
Y1 - 1992
N2 - The live, aromatic dependent Shigella flexneri Y vaccine strain SFL124, with a deleted aroD gene, was tested for safety and immunogenicity in 21 healthy adult volunteers. A single dose of 2 × 109 live bacteria was given orally to ten volunteers, whereas 11 received three doses every other day. The vaccine was excreted for 4.2 days and was well tolerated by 90.5% of the vaccinees. Only 2 of 21 (9.5%) after the first dose had a self-limiting diarrhoea lasting 1 day; of volunteers given one dose only 3 of 10 showed anti-lipopolysaccharide (LPS) and anti-invasion plasmid coded antigen (Ipa) responses in serum. A faecal antibody response to LPS and Ipa was seen in six and three persons, respectively. Volunteers given three doses reacted with serum anti-LPS ( 9 11) and anti-Ipa ( 5 11) antibody responses. In stool, anti-LPS and anti-Ipa responses were detected in nine and eight volunteers, respectively. A booster dose of 2 × 109 bacteria given to six volunteers in the three-dose group 9-10 months later elicited high stool sIgA responses, indicating a strong mucosal memory, and was accompanied by a short excretion period of SFL124 (1.8 versus 4.2 days, p < 0.05). The vaccination also elicited antibody-secreting cell (ASC) responses against LPS in peripheral blood: the three doses of the vaccine resulted in a stronger response than did the single dose, while the booster dose elicited only a limited ASC response. Volunteers previously exposed to shigellae exhibited stronger anti-Ipa responses in serum and stool suggestive of an immunological memory to the Ipa. The results indicate that SFL124 is a safe live vaccine strain inducing specific immune responses against LPS and Ipa with a mucosal immune memory lasting for at least 9 months.
AB - The live, aromatic dependent Shigella flexneri Y vaccine strain SFL124, with a deleted aroD gene, was tested for safety and immunogenicity in 21 healthy adult volunteers. A single dose of 2 × 109 live bacteria was given orally to ten volunteers, whereas 11 received three doses every other day. The vaccine was excreted for 4.2 days and was well tolerated by 90.5% of the vaccinees. Only 2 of 21 (9.5%) after the first dose had a self-limiting diarrhoea lasting 1 day; of volunteers given one dose only 3 of 10 showed anti-lipopolysaccharide (LPS) and anti-invasion plasmid coded antigen (Ipa) responses in serum. A faecal antibody response to LPS and Ipa was seen in six and three persons, respectively. Volunteers given three doses reacted with serum anti-LPS ( 9 11) and anti-Ipa ( 5 11) antibody responses. In stool, anti-LPS and anti-Ipa responses were detected in nine and eight volunteers, respectively. A booster dose of 2 × 109 bacteria given to six volunteers in the three-dose group 9-10 months later elicited high stool sIgA responses, indicating a strong mucosal memory, and was accompanied by a short excretion period of SFL124 (1.8 versus 4.2 days, p < 0.05). The vaccination also elicited antibody-secreting cell (ASC) responses against LPS in peripheral blood: the three doses of the vaccine resulted in a stronger response than did the single dose, while the booster dose elicited only a limited ASC response. Volunteers previously exposed to shigellae exhibited stronger anti-Ipa responses in serum and stool suggestive of an immunological memory to the Ipa. The results indicate that SFL124 is a safe live vaccine strain inducing specific immune responses against LPS and Ipa with a mucosal immune memory lasting for at least 9 months.
KW - Shigella flexneri
KW - humans
KW - immunogenicity
KW - oral vaccination
KW - safety
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U2 - 10.1016/0264-410X(92)90070-Z
DO - 10.1016/0264-410X(92)90070-Z
M3 - Article
C2 - 1598788
AN - SCOPUS:0026525072
SN - 0264-410X
VL - 10
SP - 395
EP - 404
JO - Vaccine
JF - Vaccine
IS - 6
ER -