| Autor: |
Kossaczka, Zuzana, Lin, Feng-Ying C., Ho, Vô Anh, Thuy, Nguyen Thi Thanh, Bay, Phan Van, Thanh, Tran Cong, Khiem, Ha Ba, Trach, Dang Duc, Karpas, Arthur, Hunt, Steven, Bryla, Dolores A., Schneerson, Rachel, Robbins, John B., Szu, Shousun C. |
| Zdroj: |
Infection and Immunity; November 1999, Vol. 67 Issue: 11 p5806-5810, 5p |
| Abstrakt: |
ABSTRACTThe capsular polysaccharide of Salmonella typhi,Vi, is an essential virulence factor and a protective vaccine for people older than 5 years. The safety and immunogenicity of two investigational Vi conjugate vaccines were evaluated in adults, 5- to 14-year-old children, and 2- to 4-year-old children in Vietnam. The conjugates were prepared with Pseudomonas aeruginosarecombinant exoprotein A (rEPA) as the carrier, using eitherN-succinimidyl-3-(2-pyridyldithio)-propionate (SPDP; Vi-rEPA1) or adipic acid dihydrazide (ADH; Vi-rEPA2) as linkers. None of the recipients experienced a temperature of >38.5°C or significant local reactions. One injection of Vi-rEPA2into adults elicited a geometric mean (GM) increase in anti-Vi immunoglobulin G (IgG) from 9.62 enzyme-linked immunosorbent assay units/ml (EU) to 465 EU at 6 weeks; this level fell to 119 EU after 26 weeks. In the 5- to 14-year-old children, anti-Vi IgG levels at 6 weeks elicited by Vi-rEPA2, Vi-rEPA1, and Vi were 169, 22.8, and 18.9 EU, respectively (P= 0.0001 for Vi-rEPA1and Vi with respect to Vi-rEPA2). At 26 weeks, the anti-Vi IgG levels for recipients of Vi-rEPA2, Vi-rEPA1, and Vi were 30.0, 10.8, and 13.4 EU, respectively (P< 0.001 for Vi-rEPA1and Vi with respect to Vi-rEPA2); all were higher than the preinjection levels (P= 0.0001). Vi-rEPA2also elicited the highest anti-Vi IgM and IgA levels of the three vaccines. In the 2- to 4-year-old children at 6 weeks following the first injection, Vi-rEPA2elicited an anti-Vi IgG level of 69.9 EU compared to 28.9 EU for Vi-rEPA1(P= 0.0001). Reinjection increased Vi antibody levels from 69.9 to 95.4 EU for Vi-rEPA2and from 28.9 to 83.0 EU for Vi-rEPA1. At 26 weeks, anti-Vi IgG levels remained higher than those at preinjection (30.6 versus 0.18 for Vi-rEPA2and 12.8 versus 0.33 for Vi-rEPA1; P= 0.0001 for both). Vi vaccine is recommended for individuals of 5 years of age or older. In the present study, the GM level of anti-Vi IgG elicited by two injections of Vi-rEPA2in the 2- to 4-year-old children was higher than that elicited by Vi in the 5- to 14-year-old children (30.6 versus 13.4; P= 0.0001). The safety and immunogenicity of the Vi-rEPA2conjugate warrant further investigation. |
| Databáze: |
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