Influence of immunization dose schemes on immunoprotective response to recombinant signaling protein 14-3-3 of Schistosoma japonicum / 中华预防医学杂志

<p><b>OBJECTIVE</b>To discuss the optimal immunization dose by observing the immunoprotective effects of different doses of recombinant Schistosoma japonicum (Chinese strain) signaling protein 14-3-3 (rSj14-3-3).</p><p><b>METHODS</b>Sj14-3-3 gene was amplified by reverse transcriptase PCR (RT-PCR), subcloned into prokaryotic expression vector pET28a, then transformed into E.coli to express by inducing. Purified rSj14-3-3 was prepared through SDS polyacrylamide gel electrophoresis (SDS-PAGE), electroelution, dialysis, then BALB/c mice were divided into 5 groups and immunized in rSj14-3-3 protein followed by challenging infection (the 1st, 2nd, and 3rd groups were immunized in 50 microg, 100 microg and 300 microg antigen, respectively. The 4th, 5th groups were immunized in Freund's adjuvant and normal saline controls). After 6 weeks of challenging infection, the mice were killed and the worm and egg reduction rates were calculated. And the mice sera in different time were taken to examine the specific anti-Sj14-3-3 IgG.</p><p><b>RESULTS</b>rSj14-3-3 protein was expressed successfully. After immunizing and challenging, worm reduction was found to be 28.20% in the 1st group, 43.10% in the 2nd group, 40.00% in the 3rd group, respectively. Number of eggs in liver tissue was reduced by 41.80%, 57.50%, 55.70%, respectively. Compared the results of the tested groups to the controls, the differences were of significance by t-test (worm reduction rate: t = 6.8 in the 1st group, t = 8.7 in the 2nd group, t = 7.3 in the 3rd group, P < 0.01 in all tested groups. Egg reduction rate at the group's number above: t = 11.23, t = 11.54, t = 7.99, P < 0.01 in all tested groups). As compared the results between the tested groups by chi(2), the differences were of significance between the 1st and the 2nd groups (worm reduction rate: chi(2) = 8.96, P < 0.05; egg reduction rate: chi(2) = 15.69, P < 0.05), between the 1st and the 3rd groups, the differences were also of significance (worm reduction rate: chi(2) = 6.52, P < 0.05; egg reduction rate: chi(2) = 12.52, P < 0.05). The difference was not of significance between the 2nd and the 3rd groups (worm reduction rate: chi(2) = 1.20, P > 0.05; egg reduction rate: chi(2) = 0.93, P > 0.05). In all tested groups, total anti-Sj14-3-3 specific IgG rose markedly. IgG(1) and IgG(2a) subtypes were high, but IgG(2b) and IgG(3) were near the background in four subtypes tested.</p><p><b>CONCLUSION</b>Immunoprotection of rSj14-3-3 should have some relations with immunization dose, and the protection obtained from immunizing mice by using 100 microg antigen was the best.</p>

Longitudinal investigation and experimental studies on thelaziasis and the intermediate host of Thelazia callipaeda in Guanghua county of Hubei province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To verify houseflies Musca spp. as the intermediate host of Thelazia callipaeda and reveal epidemiological situation of thelaziasis in Hubei province.</p><p><b>METHODS</b>Dogs eyes infected with T. callipaeda, 400 houseflies Musca and 259 fruitflies Amiota okadai in the city of Laohekou city (previously named as Guanghua county) of Hubei province had been investigated since September 2000. The newborn larvae of T. callipaeda from Laohekou suburbs were fed to houseflies Musca and A. okadai. Larvae used for the study were isolated from female T. callipaeda in laboratory and the susceptibility to houseflies Musca and A. okadai was observed.</p><p><b>RESULTS</b>Twenty-one dogs from Laohekou, the original epidemic areas of thelaziasis were examined and 7 positive dogs in 21 (33.3%) and 11 T. callipaeda (9 females and 2 males) were identified. From 1975 to 2000, no thelaziasis cases were found through retrospective surveys. These 200 houseflies Musca and 135 A. okadai were dissected for examination but showed all negative with the infection. However, newborn larvae of T. callipaeda were used to experimentally infect 112 houseflies Musca and 84 A. okadai and all infected flies were examined on the 20th day after inoculation. As a consequence, houseflies Musca failed to be infected but 9 in 84 (10.7%) A. okadai were positive. 26 infective larvae of T. callipaeda were obtained and 21 of them were inoculated into right eye of one rabbit. The female worm began to produce newborn larvae in 37 days after infection and 3 adult T. callipaeda (two females and one male) were obtained.</p><p><b>CONCLUSIONS</b>Fruitflies A. okadai from Hubei province were susceptible to T. callipaeda, which was similar to the result of experimental studies in Anhui province. This survey further confirmed that A. okadai was the intermediate host of T. callipaeda but not houseflies Musca. Infective resources (adult dogs, for instance) had been under controlled thus human thelaziasis had been eradicated in this rural area.</p>