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Vaccinated Individuals (vaccinated + individual)
Selected AbstractsSafety and immunogenicity of Sinovac's prototype pandemic influenza H5N1 vaccines: a review on clinical trialsINFLUENZA AND OTHER RESPIRATORY VIRUSES, Issue 6 2008Yuan-Zheng Qiu Abstract, Sinovac Biotech started to develop prototype pandemic influenza H5N1 vaccines in March 2004. On 2 April 2008, Sinovac's inactivated, aluminium-adjuvanted, whole-virion prototype pandemic influenza A (H5N1) vaccine (PanFluÔ) was granted production licensure by the China regulatory authority State Food and Drug Administration. The whole-virion H5N1 vaccine was manufactured in embryonated hens' eggs using the reassortant strain NIBRG-14 (A/Vietnam/1194/2004-A/PR/8/34) as vaccine virus. It showed good safety, immunogenicity and cross-reactivity in immunologically naïve adults. In primed adults, the vaccine induced a strong booster response. Plasma from a vaccinated individual showed a beneficial effect following passive immunotherapy of an H5N1 human infection case. This article reviews the process, status and results of clinical evaluation of Sinovac's whole- and split-virion H5N1 vaccines by focusing on the whole-virion vaccine. [source] Variants of two major T cell epitopes within the hepatitis B surface antigen are not recognized by specific T helper cells of vaccinated individualsHEPATOLOGY, Issue 2 2002Tanja Bauer Several naturally occurring variants of immunogenic T cell epitopes were identified within the hepatitis B surface antigen (HBsAg). The effect of these variants on the cellular immune response was studied in individuals vaccinated against HBV. Class-II restricted T-cell responses of 30 vaccinees were analyzed after stimulation of peripheral blood mononuclear cells (PBMCs) with 4 synthetic peptides representing the 4 T-cell epitopes of HBsAg known as of yet. The 2 epitopes P1 (aa 16-33) and P4 (aa 213-226) could be identified as the dominant ones in our vaccinees by proliferation assays and enzyme-linked immunospot assays. Responses to these epitopes were compared with responses to their naturally occurring variants found in HBV isolates of chronic virus carriers. Three of 11 variants of epitope P4 led to a complete loss of T-cell reactivity in 4 of 10 donors, all of whom reacted well to the corresponding wild-type sequence. The remaining 6 donors recognized these variants as well as the vaccine epitope. Similarly, 3 P1-variants of the 12 found induced only a significantly reduced reactivity in 4 of 10 donors, whereas they led to a normal response in the other 6 individuals. Stimulation of T cells also induced the secretion of antibody to HBsAg (anti-HBs) by specific B cells; however, those peptides that failed to activate T cells were also unable to cause any significant anti-HBs production. In conclusion, our results suggest an immune escape of certain mutant strains of HBV in vaccinated individuals could exist at the T-cell level. [source] Diagnosis of tuberculosis: Available technologies, limitations, and possibilitiesJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 5 2003Sanjay K. Garg Abstract Rapid diagnosis and treatment are important for preventing transmission of Mycobacterium tuberculosis. However, the diagnosis of tuberculosis continues to pose serious problems, mainly because of difficulties in differentiating between patients with active tuberculosis and those with healed lesions, normal mycobacterium boris BCG (Bacillus Calmette Guerin) vaccinated individuals, and unvaccinated Manteux positives. Physicians still rely on conventional methods such as Ziehl-Neelsen (ZN) staining, fluorochrome staining, sputum culture, gastric lavage, and other non-traditional methods. Although the tuberculin test has aided in the diagnosis of tuberculosis for more than 85 years, its interpretation is difficult because sensitization with nontuberculous mycobacteria leads to false-positive tests. There have been numerous unsuccessful attempts to develop clinically useful serodiagnostic kits for tuberculosis. A number of proteinaceous and nonprotein antigens (such as acyltrehaloses and phenolglycolipids) have been explored from time to time for the development of such assays but they have not proved to be clinically useful. It has been difficult to develop an ELISA utilizing a suitable antigen because M. tuberculosis shares a large number of antigenic proteins with other microorganisms that may or may not be pathogenic. With the advent of molecular biology techniques, there have been significant advances in nucleic acid-based amplification and hybridization, which are helping to rectify existing flaws in the diagnosis of tuberculosis. The detection of mycobacterial DNA in clinical samples by polymerase chain reaction (PCR) is a promising approach for the rapid diagnosis of tuberculous infection. However, the PCR results must be corrected for the presence of inhibitors as well as for DNA contamination. In the modern era of genetics, marked by proteomics and genomics, the day is not far off when DNA chip-based hybridization assays will instantly reveal mycobacterial infections. J. Clin. Lab. Anal. 17: 155,163, 2003. © 2003 Wiley-Liss, Inc. [source] Immunogenicity of CIGB-230, a therapeutic DNA vaccine preparation, in HCV-chronically infected individuals in a Phase I clinical trialJOURNAL OF VIRAL HEPATITIS, Issue 3 2009L. Alvarez-Lajonchere Summary., Hepatitis C virus (HCV) is a worldwide health problem. No vaccine is available against this pathogen and therapeutic treatments currently in use are of limited efficacy. In the present study, the immunogenicity of the therapeutic vaccine candidate CIGB-230, based on the mixture of pIDKE2, a plasmid expressing HCV structural antigens, with a recombinant HCV core protein, Co.120, was evaluated. CIGB-230 was administered by intramuscular injection on weeks 0, 4, 8, 12, 16 and 20 to 15 HCV-chronically infected individuals, non-responders to previous treatment with interferon (IFN) plus ribavirin. Interestingly, following the final immunization, neutralizing antibody responses against heterologous viral pseudoparticles were modified in eight individuals, including six de novo responders. In addition, 73% of vaccinees exhibited specific T cell proliferative response and T cell IFN-gamma secretory response 24 weeks after primary immunization with CIGB-230. Furthermore, 33.3% of individuals developed de novo cellular immune response against HCV core and the number of patients (46.7% at the end of treatment) with cellular immune response against more than one HCV structural antigen increased during vaccination (P = 0.046). In addition, despite persistent detection of HCV RNA, more than 40% percent of vaccinated individuals improved or stabilized liver histology, particularly reducing fibrosis, which correlated with cellular immune response against more than one HCV antigen (P = 0.0053). In conclusion, CIGB-230 is a promising candidate for effective therapeutic interventions based on its ability for enhancing the immune response in HCV chronically infected individuals. [source] Differential in vitro CD4+/CD8+ T-cell response to live vs. killed Leishmania majorPARASITE IMMUNOLOGY, Issue 2 2010M. NATEGHI ROSTAMI Summary Clinical trials of killed Leishmania vaccines showed a limited efficacy compared with leishmanization (LZ). The reason for this difference in protection against cutaneous leishmaniasis (CL) is not known and in vivo studies on T-cell function may provide valuable information. Nevertheless, there are limited studies on the nature of the stimulatory effects of live vs. killed parasites on human T cells in vitro. A total of nine Leishmanin Skin Test+ volunteers with a history of self-healing CL (HCL) and seven healthy volunteers were included in this study. 5,6-carboxyfluroescein diacetate succinimidyl ester-labelled CD4+/CD8+ lymphocytes were cultured with killed Leishmania Lysate (Killed LL) or live Leishmania major (Live LM) and analysed for proliferation using flow cytometry. Culture supernatants were used for cytokine titration. In HCL volunteers, upon stimulation with killed LL, the number of proliferated CD4+/CD8+ cells was significantly more than that of unstimulated (P < 0·001) or live LM stimulated (P < 0·05) cells, or cells from controls (CD4+/CD8+: P < 0·05/P < 0·001). Stimulation of CD4+ cells with Live LM (P < 0·001) or Killed LL (P < 0·05) induced a significantly higher IFN-, production compared with that of controls, but Live LM induced significantly (P < 0·05) more IFN-, than Killed LL. A significantly (P < 0·05) higher IFN-, production was observed when CD8+ cells were stimulated with Live LM. Cells from HCL volunteers showed significantly more IL-10 production to Live LM stimulation compared with that of controls (CD4+: P < 0·05 /CD8+: P < 0·001) or cells stimulated with Killed LL (CD4+/CD8+: P < 0·001/P < 0·0005). Whereas Killed LL induced more proliferation response in purified T cells, Live LM induced cytokine production without significant induction of proliferation. The results from healed CL volunteers in this study could be implicated in further studies on T-cell response in vaccinated individuals. [source] | ||||||||||