METHODOLOGY/PRINCIPAL FINDINGS: With the availability of the B. pseudomallei whole genome sequence, we undertook to identify genes encoding the known immunogenic outer membrane protein A (OmpA). Twelve OmpA domains were identified and ORFs containing these domains were fully annotated. Of the 12 ORFs, two of these OmpAs, Omp3 and Omp7, were successfully cloned, expressed as soluble protein and purified. Both proteins were recognised by antibodies in melioidosis patients' sera by Western blot analysis. Purified soluble fractions of Omp3 and Omp7 were assessed for their ability to protect BALB/c mice against B. pseudomallei infection. Mice were immunised with either Omp3 or Omp7, subsequently challenged with 1x10(6) colony forming units (cfu) of B. pseudomallei via the intraperitoneal route, and examined daily for 21 days post-challenge. This pilot study has demonstrated that whilst all control unimmunised mice died by day 9 post-challenge, two mice (out of 4) from both immunised groups survived beyond 21 days post-infection.
CONCLUSIONS/SIGNIFICANCE: We have demonstrated that B. pseudomallei OmpA proteins are immunogenic in mice as well as melioidosis patients and should be further assessed as potential vaccine candidates against B. pseudomallei infection.
MATERIALS AND METHODS: From 1997 to 1999, 55 patients with FIGO stage Ib1 lymph nodes-negative cervical carcinoma limited to the cervix were prescribed RT following radical surgery, based on their RS, as follows: RS <40, RT is omitted; RS >40 to <120, modified (smaller) field RT; and RS >120, standard field pelvic RT. Their incidence and site of recurrence were compared with a similar cohort of 40 patients who were treated prior to 1997.
RESULTS: Prior to 1997, of the 40 patients, 10 patients were given standard field RT. There were 2 (5%) recurrent diseases. The mean duration of follow-up was 61.6 months (range, 1 to 103 months). The RS of 23 of the 30 patients who were not given RT were available. The mean RS was 22 with 5 patients having a score of >40. From 1997 onwards, of the 55 patients, 28 (51%) did not require RT, 13 (23%) were treated with modified (smaller) field RT and 14 (26%) were given standard field RT. There were 2 (3.6%) cases of relapse. The mean duration of follow-up was 36.4 months (range, 5 to 60 months). All patients with a RS of <40 did not suffer any relapse. Their survival outcomes were better when compared to patients who did not have any RT in the GOG Study.
CONCLUSIONS: The results of this study indicated that postoperative adjuvant RT given to patients with a high GOG RS of >120, significantly improved their 5-year recurrence rate and disease-free survival, as compared with the similar group of patients who were without adjuvant therapy in the GOG study. Patients with a GOG risk-score of <40 may be safely spared from adjuvant pelvic RT. The current treatment protocol did not compromise the outcome in patients, compared with the use of a less precise treatment protocol in the past.