Biomedical subjects

Cheng-Tao Lin

Publications and source records attributed to Cheng-Tao Lin.

16 recordsLinked to original sources

PubMed2006

Novel codon-optimized GM-CSF gene as an adjuvant to enhance the immunity of a DNA vaccine against HIV-1 Gag.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a potent immunomodulatory cytokine. Here we generated a novel codon-optimized murine GM-CSF gene as an adjuvant. The codon-optimized GM-CSF gene significantly increased protein expression levels in all cells tested. Although injection of the wild-type GM-CSF plasmids adjuvanted HIV-1 Gag DNA vaccine induced detectable immune responses, co-administration of plasmids encoding the codon-optimized GM-CSF sequence with the DNA vaccine resulted in a strong antibody and CTL responses and a protective immune response against infection with recombinant vaccinia virus expressing HIV-1 Gag. This novel codon-optimized GM-CSF gene offers a practical molecular strategy for potentiating immune responses to vaccines as well as other immunotherapeutic strategies.

AIDS Vaccines↗

PubMed2006

Maintenance of CD8 effector T cells by CD4 helper T cells eradicates growing tumors and promotes long-term tumor immunity.

Human papillomavirus, particularly type 16 (HPV-16), is present in more than 99% of cervical cancers, and oncogenic HPV infection is one of the most important etiologies. It is now clear that CD4(+) T cells play an important role in controlling HPV-associated lesions because immunocompromised patients have a higher frequency of HPV-associated lesions. In the current study, we characterized the significance of CD4(+) T cells in the generation of E7-specific CD8(+) T cell immune responses in mice vaccinated with SINrep5-E7/HSP70 and boosted with vac-E7/HSP70. In addition, we characterized the contribution of CD4(+) T cells to the long-term antitumor effects. We found that vaccination with CD4 depletion significantly reduced the number of E7-specific CD8(+) T cells in mice. Furthermore, CD4(+) T cells are important for the long-term anti-tumor effects generated by vaccination with SINrep5-E7/HSP70 and booster with vac-E7/HSP70. Thus, CD4 T cells clearly have an important role in successful tumor immunity and maintenance of long-term tumor antigen-specific memory responses in vaccinated mice with established tumors.

Animals↗

PubMed2006

A DNA vaccine encoding a codon-optimized human papillomavirus type 16 E6 gene enhances CTL response and anti-tumor activity.

The HPV oncoproteins E6 and E7 are consistently expressed in HPV-associated cancer cells and are responsible for their malignant transformation. Therefore, HPV E6 and E7 are ideal target antigens for developing vaccines and immunotherapeutic strategies against HPV-associated neoplasms. Recently, it has been demonstrated that codon optimization of the HPV-16 E7 gene resulted in highly efficient translation of E7 and increased the immunogenicity of E7-specific DNA vaccines. Since vaccines targeting E6 also represent an important strategy for controlling HPV-associated lesions, we developed a codon-optimized HPV-16 E6 DNA vaccine (pNGVL4a-E6/opt) and characterized the E6-specific CD8+ T cell immune responses as well as the protective and therapeutic anti-tumor effects in vaccinated C57BL/6 mice. Our data indicated that transfection of human embryonic kidney cells (293 cells) with pNGVL4a-E6/opt resulted in highly efficient translation of E6. In addition, vaccination with pNGVL4a-E6/opt significantly enhanced E6-specific CD8+ T cell immune responses in C57BL/6 mice. Mice vaccinated with pNGVL4a-E6/opt are able to generate potent protective and therapeutic antitumor effects against challenge with E6-expressing tumor cell line, TC-1. Thus, DNA vaccines encoding a codon-optimized HPV-16 E6 may be a promising strategy for improving the potency of prophylactic and therapeutic HPV vaccines with potential clinical implications.

Analysis of Variance↗

PubMed2006

Low value of [18F]-fluoro-2-deoxy-D-glucose positron emission tomography in primary staging of early-stage cervical cancer before radical hysterectomy.

PURPOSE: The role of positron emission tomography (PET) with [18F]-fluoro-2-deoxy-D-glucose (FDG) in early-stage cervical cancer is unclear. We aimed to investigate the clinical benefit of FDG-PET in primary staging before radical hysterectomy and pelvic lymphadenectomy (RH-PLND). PATIENTS AND METHODS: Patients with untreated stage IA2 to IIA adenocarcinoma (AD) or adenosquamous carcinoma (ASC) or nonbulky (< or = 4 cm) squamous cell carcinoma cervical cancer with magnetic resonance imaging (MRI) -defined negative nodal metastasis were enrolled onto a prospective study with a two-stage design. All patients had a preoperative dual-phase FDG-PET, technetium-99m-sulfur colloid lymphoscintigraphy, and intraoperative sentinel lymph node (LN) detection at RH-PLND. The gold standard of LN metastasis is histologic. A sample size of 120 patients was calculated to fit study aims (diagnostic efficacy of PET and sentinel LN sampling). An interim analysis was performed when 60 patients were accrued, which led to the current report. RESULTS: There were 36 SCCs, 20 ADs, and four ASCs. Of the 60 patients, 10 (16.7%) had pelvic LN metastases, and one (1.7%) had para-aortic LN (PALN) metastasis histologically. FDG-PET detected the single PALN metastasis (one of one patient) but detected only one (10%) of the 10 pelvic LN metastases. The PET false-negative pelvic LN micrometastases measured a median of 4.0 x 3.0 mm (range, 0.5 x 0.5 to 7 x 6 mm). The second stage of this trial will be continued without PET. CONCLUSION: This study shows that dual-phase FDG-PET has little value in primary, nonbulky, stage IA2 to IIA and MRI-defined, LN-negative cervical cancer.

Adult↗

PubMed2006

Comparison between the Hybrid Capture II Test and an SPF1/GP6+ PCR-based assay for detection of human papillomavirus DNA in cervical swab samples.

We compared the efficacy of human papillomavirus (HPV) DNA detection between a PCR-based genechip (Easychip HPV Blot [hereafter referred to as HPV Blot]; King Car, Taiwan) method and Hybrid Capture II (HCII; Digene, Gaithersburg, MD) in women with previous normal (n = 146) or abnormal (> or =atypical squamous cells of undetermined significance [ASCUS] [n = 208]) cytology. A total of 354 cervical swab samples were collected for HPV DNA assay by both HCII and SPF1/GP6+ PCR followed by HPV Blot tests. Colposcopy-directed biopsy was performed if clinically indicated. Of the 354 samples, HPV-positive rates by these two methods (HCII and HPV Blot) were 12.6% and 18.2% in 143 normal samples, 36.2% and 45.7% in 105 ASCUS samples, 57.4% and 57.4% in 94 low-grade squamous intraepithelial lesion samples, and 83.3% and 75.0% in 12 high-grade squamous intraepithelial lesion samples, respectively. The concordance of HPV Blot and HCII was 80.8% (286/354), and the agreement between the methods (kappa value, 0.68) was substantial. Discrepancies were further investigated by at least one of the following three methods: direct sequencing, type-specific PCR, and HPV Blot genotyping of cervical biopsy tissue. In the 15 HCII-positive samples, HPV Blot detected only non-HCII HPV genotypes; results of further verification methods were consistent with the latter test in the 15 samples. Of the 20 samples with HCII-negative and HPV Blot-positive results, 18 were found to contain the 13 HCII high-risk genotypes by verification methods. In only 16.7% (3/18) of the HCII-positive but HPV Blot-negative samples, further studies detected the 13 HCII genotypes. We conclude that HPV Blot seemed comparable to HCII for detection of HPV DNA in cervical swab samples.

Base Sequence↗

PubMed2005

Enhancement of DNA vaccine potency through linkage of antigen gene to ER chaperone molecules, ER-60, tapasin, and calnexin.

DNA vaccines have emerged as an attractive approach for generating antigen-specific immunotherapy. Strategies that enhance antigen presentation may potentially be used to enhance DNA vaccine potency. Previous experiments showed that chimeric DNA vaccines utilizing endoplasmic reticulum (ER) chaperone molecules, such as Calreticulin (CRT), linked to an antigen were capable of generating antigen-specific CD8+ T cell immune responses in vaccinated mice. In this study, we tested DNA vaccines encoding the ER chaperone molecules ER-60, tapasin (Tap), or calnexin (Cal), linked to human papillomavirus type 16 (HPV-16) E7 for their abilities to generate E7-specific T cell-mediated immune responses and antitumor effects in vaccinated mice. Our results demonstrated that vaccination with DNA encoding any of these chaperone molecules linked to E7 led to a significant increase in the frequency of E7-specific CD8+ T cell precursors and generated stronger antitumor effects against an E7-expressing tumor in vaccinated mice compared to vaccination with wild-type E7 DNA. Our data suggest that DNA vaccines employing these ER chaperone molecules linked to antigen may enhance antigen-specific CD8+ T cell immune responses, resulting in a significantly more potent DNA vaccine.

Animals↗

PubMed2005

Ultrasound and urodynamic comparison between caudocranial and craniocaudal tension-free vaginal tape for stress urinary incontinence.

OBJECTIVES: To compare the efficacy and safety of the conventional caudocranial tension-free vaginal tape (TVT) procedure and craniocaudal TVT procedure for the treatment of primary stress urinary incontinence. METHODS: Ninety patients with urodynamic stress incontinence and without prolapse underwent a caudocranial TVT (45 women) or craniocaudal TVT (45 women) procedure. The two patient groups were comparable in terms of age, parity, body weight, previous pelvic surgery, and menopausal status. Both methods were performed under local anesthesia with adequate sedation. Introital ultrasound evaluation on the mid-urethra TVT tapes and urodynamic evaluation was performed before and after surgery. RESULTS: The average follow-up period for caudocranial TVT and craniocaudal TVT was 1.9 years and 1.4 years, respectively. Objective evaluations were performed at similar times at 1 year postoperatively. No significant differences were found in the cure rate at 88.9% (40 of 45 women) after caudocranial TVT and 91.1% (41 of 45 women) after craniocaudal TVT (P = 1.000). The intraoperative complications were minor. No patient had long-term voiding difficulty or required long-term catheterization. Both groups had the vaginal tape implanted at the mid-urethra, with a urethral knee angle observed during maximal straining. A more proximal tape position, less elasticity of the tape, and more obstruction by the sling were found using the craniocaudal approach. Postoperative dysfunctional voiding was minor. CONCLUSIONS: The caudocranial and craniocaudal TVT procedures are highly effective, minimally invasive, and safe procedures in the treatment of urinary stress incontinence. The variations in implanted tape position and postoperative sling obstruction were most likely caused by the mode of insertion.

Female↗

PubMed2004

Positron emission tomography for unexplained elevation of serum squamous cell carcinoma antigen levels during follow-up for patients with cervical malignancies: a phase II study.

BACKGROUND: During follow-up for patients with cervical carcinoma, elevation of serum squamous cell carcinoma antigen (SCC-Ag) levels in the absence of detectable recurrent lesions presents a diagnostic and therapeutic challenge. In the current prospective study, the authors evaluated the use of fluorine-18-labeled fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) to detect disease recurrence in this setting. METHODS: Women with cervical carcinoma who experienced complete responses to primary treatment or salvage therapy and who had no evidence of recurrent disease as detected by conventional methods but had serum SCC-Ag levels > or = 2.0 ng/mL on 2 consecutive occasions were eligible for the study. PET was performed within 2 weeks after the completion of conventional studies for the assessment of recurrence. RESULTS: Twenty-seven consecutive patients were registered for the current study. PET findings were positive for 19 patients: 14 who had a distant lesion or lesions, 2 who had a local lesion or lesions, and 3 who had both local and distant lesions. Of these 19 patients, 17 were confirmed to have recurrent disease; the remaining two were found to be free of disease but had severe anthracosis in the PET-positive mediastinal lymph nodes. Seven of the eight patients with negative PET findings were not found to have recurrent disease on follow-up. Overall, PET detected FDG-avid lesions in 17 (94%; P < 0.001) of the 18 patients with recurrent disease. Seven of these 18 patients received therapy with curative intent; complete control was achieved in 6, four of whom currently are alive and free of disease. The addition of PET in the current setting curbed the use of futile curative therapy and significantly increased overall survival for patients in the current cohort compared with a historical group of 30 consecutive patients who had elevated SCC-Ag levels as a first sign of recurrence. CONCLUSIONS: PET expedited the detection of recurrent cervical carcinoma in patients with unexplained elevation of SCC-Ag levels. Such expedited detection may have positive effects on patient survival.

Antigens, Neoplasm↗

PubMed2004

Enhancement of DNA vaccine potency by coadministration of a tumor antigen gene and DNA encoding serine protease inhibitor-6.

Serine protease inhibitor 6 (SPI-6), also called Serpinb9, inhibits granzyme B and thus may provide a method for delaying apoptotic cell death in dendritic cells. We have previously enhanced DNA vaccine potency by targeting antigen to MHC antigen presentation pathways, using proteins such as Mycobacterium tuberculosis heat shock protein 70, calreticulin, domain II of Pseudomonas aeruginosa exotoxin A, or the sorting signal of the lysosome-associated membrane protein type 1. In this study, we explored intradermal coadministration of DNA encoding SPI-6 with DNA constructs encoding human papillomavirus type 16 E7 linked to these intracellular targeting molecules for its ability to generate E7-specific CD8+ T-cell immune responses and E7-specific antitumor effects. This combination of strategies resulted in significantly increased E7-specific CD8+ T-cell and CD4+ Th1-cell responses, enhanced tumor treatment ability, and stronger tumor protection when compared with vaccination without SPI-6. Among these targeting strategies tested, mice vaccinated with Sig/E7/lysosome-associated membrane protein type 1 mixed with SPI-6 showed the greatest fold increase in E7-specific CD8+ T cells ( approximately 5-fold). Vaccination with a nonfunctional mutant of SPI-6 did not result in immune enhancement, indicating that enhancement was dependent on the antiapoptotic function of SPI-6. Our results suggest that DNA vaccines combining strategies that enhance MHC class I and II antigen processing with SPI-6 have potential clinical implications for control of viral infection and neoplasia.

Animals↗

PubMed2004

Usefulness of human papillomavirus testing in the follow-up of patients with high-grade cervical intraepithelial neoplasia after conization.

OBJECTIVE: We aimed to define the adjunctive role of human papillomavirus (HPV) DNA testing in the follow-up of high-grade cervical intraepithelial neoplasia (CIN) after conization. STUDY DESIGN: We analyzed a consecutive series of 2,154 patients who received conization. Patients who had cone diagnosis of cervical cancer or CIN 1, a hysterectomy within 12 weeks after conization, and no follow-up data were excluded. The remaining 765 patients (monitored by Pap smears, colposcopy with or without high-risk HPV DNA testing) were analyzed. RESULTS: Of the 765 patients, 279 had CIN at cone margin or endocervix (group A) while 486 were both margin- and endocervix-free (group B). The 3-year cumulative rate of residual/recurrent high-grade CIN was 10.3% (95% CI, 6.9-13.7). HPV follow-up status (P=.015), margin status (P=.001), and follow-up cervical cytology (P<.0001) were significant predictors for residual/recurrent high-grade CIN by multivariate analysis. Four high-grade CINs and 1 microinvasive carcinoma of group A were detected initially by HPV testing, while 48.3% (199/410) of those without recurrent/persistent high-grade CIN still had persistent HPV infection. CONCLUSION: HPV DNA testing is useful in the follow-up and understanding of the natural history after conization for high-grade CIN.

Adenocarcinoma↗

PubMed2004

A histologic and immunohistochemical analysis of defective vaginal healing after continence taping procedures: a prospective case-controlled pilot study.

OBJECTIVE: The purpose of this study was to investigate vaginal rejection of polypropylene mesh after continence taping procedures. STUDY DESIGN: Of 700 women who had undergone the procedures, 17 women with sling erosion and 7 women with voiding difficulty or symptomatic vagina prolapse (control subjects) underwent histopathologic evaluation and immunohistochemistry. RESULTS: Seven women whose condition was not responding to conservative treatment and debridements had the exposed suburethral tape excised, which revealed predominant foreign body reaction and fragmented mesh that was surrounded by histiocytes and dense fibrosis. Immunohistochemical analysis revealed that the cell density percentage of CD 20+ cells was statistically significantly greater in the persistent defective healing group than in either the single-debridement or control group ( P = .014 and P = .014, respectively). We found statistically significant differences between the persistent defective healing and single-debridement groups and between the former and control groups in the ratios of T and B cells ( P = .035 and P = .022, respectively). CONCLUSION: The rate of defective vaginal healing after the procedures was 2.4%. Removal of the prosthesis and surrounding tissue at various times for the 7 women resulted in histopathologic findings that suggested a immunologic reaction. The rate of persistent defective healing of the vagina was 1%.

Adult↗

PubMed2004

Defining the priority of using 18F-FDG PET for recurrent cervical cancer.

UNLABELLED: PET with 18F-FDG has shown its potential in cervical cancer. For maximizing the benefits of this new imaging technology, we aimed to define the prognostic features of recurrent cervical cancer patients for selecting appropriate candidates using 18F-FDG PET. METHODS: Patients enrolled were from 2 independent prospective studies investigating the role of 18F-FDG PET in cervical cancer patients after definitive treatment with documented failure (CTRP-018) or unexplained elevated tumor marker serum levels (CTRP-016) and proven relapse after PET. A total of 55 eligible patients received PET and CT or MRI. Lesion status was determined from pathologic results or clinical follow-up. The benefits calculated were based on treatment that was modified because of the PET findings. The Cox proportional hazards ratio (HR) was used to select independent prognostic covariates. RESULTS: Thirty-six (65.5%) patients had treatment that was modified due to PET. Primary radiation (HR = 14.62; 95% confidence interval [CI] = 2.74-77.92), squamous cell carcinoma antigen (SCC-Ag) > or = 4 ng/mL (HR = 5.82; 95% CI = 1.53-22.04), and presence of symptoms (HR = 6.24; 95% CI = 1.99-19.61) at recurrence were significant factors associated with poor survival. A scoring system using these covariates defined 3 distinct prognostic groups: score < or = 1 (HR = 1.00); score = 2 (HR = 6.91; 95% CI = 1.49-32.14); and score = 3 (HR = 60.46; 95% CI = 9.68-378.09) (P < 0.0001). CONCLUSION: Using this risk score, 18F-FDG PET may offer maximal benefits by selecting appropriate recurrent cervical cancer patients for salvage therapy with precise restaging information.

Adult↗

PubMed2003

Comparison of the CD8+ T cell responses and antitumor effects generated by DNA vaccine administered through gene gun, biojector, and syringe.

DNA vaccines have emerged as an attractive approach for antigen-specific cancer immunotherapy. We have previously linked Mycobacterium tuberculosis heat shock protein 70 (HSP70) to human papillomavirus type 16 (HPV-16) E7 in the context of a DNA vaccine. Vaccination with DNA encoding E7/HSP70 has generated a dramatic increase of E7-specific CD8+ T cell precursors and a strong antitumor effect against E7-expressing tumor (TC-1) in vaccinated mice. The success of our strategy has led to two phases I/II clinical trial proposals in patients with HPV-16 associated high-grade squamous intraepithelial lesion (HSIL) of the cervix and in patients with advanced HPV-associated head and neck squamous cell carcinoma (HNSCC). To translate our HPV DNA vaccines into the clinical domain, the efficacy of pNGVL4a-Sig/E7(detox)/HSP70 DNA vaccine and of various routes of administrations were assessed in mice. Our results indicated that pNGVL4a-Sig/E7(detox)/HSP70 DNA vaccine administered via gene gun generated the highest number of E7-specific CD8+ T cells. In addition, DNA vaccination via gene gun required the least dose to generate similar or slightly better antitumor effects compared to needle intramuscular (i.m.) and biojector administrations. Thus, our data suggest that DNA vaccination via gene gun represents the most potent regimen for DNA administration.

Animals↗

PubMed2003

Enhancing major histocompatibility complex class I antigen presentation by targeting antigen to centrosomes.

Several strategies that increase proteasomal degradation of antigen have been shown to improve MHC class I presentation of antigen. Because recent studies have demonstrated that the centrosome is a subcellular compartment rich in proteasomes, we hypothesized that targeting a tumor antigen to centrosomal compartments would enhance both the MHC class I presentation of antigen and the vaccine potency. We, therefore, created a chimera of gamma-tubulin, an established centrosomal marker, with a model tumor antigen, human papillomavirus type 16 (HPV-16) E7, in a DNA vaccine. The linkage of gamma-tubulin to E7-targeted antigen to centrosomal compartments, resulted in enhanced MHC class I presentation of E7, and led to a marked increase in the number of E7-specific CD8(+) T-cell precursors as well as a potent CD4-independent antitumor effect against an E7-expressing tumor cell line, TC-1. In addition, vaccination with gamma-tubulin/E7 DNA in transporter associated with antigen presentation (TAP)-1-knockout mice revealed that the enhancement of E7-specific CD8(+) T-cell immune responses is TAP-1-dependent. Our data suggest that the centrosome may be an important locus for MHC class I antigen processing and that targeting antigen to the centrosome can improve DNA vaccine potency.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2003

Boosting with recombinant vaccinia increases HPV-16 E7-Specific T cell precursor frequencies and antitumor effects of HPV-16 E7-expressing Sindbis virus replicon particles.

Immunotherapy using the heterologous prime-boost regimen has emerged as an attractive approach for generating antigen-specific T-cell-mediated immune responses against tumors and infectious diseases. We have previously linked the Mycobacterium tuberculosis heat-shock protein 70 (HSP70) to the HPV-16 E7 antigen creating a chimera, E7/HSP70. We found that nucleic acid vaccines encoding E7/HSP70 can generate strong antitumor immunity. Recently, replication-defective Sindbis virus replicon particle vaccines have been considered as an important vector system for vaccine development. In this study, we assessed whether the combination of E7/HSP70 Sindbis virus replicon particles (SINrep5-E7/HSP70) and E7/HSP70 vaccinia (Vac-E7/HSP70) can further enhance E7-specific immune responses using sequential vaccination. We found that priming with SINrep5-E7/HSP70 and boosting with Vac-E7/HSP70 generated the highest number of E7-specific CD8(+) T cells and best antitumor effect compared to other combinations. Moreover, our data showed that at the dosage and route of immunization used in this study, mice treated with the Sindbis virus replicon particle prime-vaccinia boost regimen generated stronger antitumor responses compared to mice treated with the DNA prime-vaccinia boost vaccine regimen. Our results encourage the use of the Sindbis virus replicon particle prime-vaccinia boost regimen in future clinical trials.

Animals↗

PubMed2003

The use of general anesthesia for the tension-free vaginal tape procedure and concomitant surgery.

BACKGROUND: To study the efficacy of performing the TVT procedure and concomitant surgery under general anesthesia in the management of urinary stress incontinent patients. METHODS: Eighty-six women with genuine stress incontinence without pelvic relaxation syndrome were surgically managed. TVT procedures were performed using vigorous manual pressure against the abdominal wall to position and adjust the vaginal tape and ensuring no lifting of the urethra by intraoperative introital ultrasonography. Concurrent gynecologic procedures were performed, if indicated. The urodynamic studies, 1-h pad-tests and introital ultrasonography were performed preoperative and 1 year after surgery. RESULT: Six women were excluded for various reasons. Among 80 patients, 74 (92.5%) were cured, five improved and one failed. No major intra-or postoperative complications occurred. After surgery, urine leakage observed on the pad-tests was significantly reduced from a mean of 24 to 1.3 g. The operating time for the TVT procedure was 23 min, and postoperative hospital stay was 2.8 days. The position and mobility of the bladder neck showed no significant difference before and after surgery. De nova detrusor instability was observed in one patient. Spontaneous voiding with adequate volume of post-void residual urine was noted for all patients by the fourth day postoperatively. Urodynamic parameters related to the voiding dysfunction showed no significant difference pre- and postoperatively. CONCLUSION: With modifications of the technique and the aid of intraoperative ultrasonography, the TVT procedure can be performed under general anesthesia. The procedure is safe, effective, minimally invasive, and has an additional benefit of correcting various coexisting gynecologic disorders in a single operation.

Adult↗