Cell-specific expression of the diphtheria toxin A-chain coding sequence induces cancer cell suicide

Objective To test whether the diphtheria toxin A (DT-A) chain coding sequence linked to murine immunoglobulin κ-light chain (Ig κ) promoter and enhancer have selective cytocidal effects on Ig κ producing cells.Methods The diphtheria toxin A gene or β-galactosidase (β-gal) gene were linked to a murine Ig κ promoter and enhancer to construct pcDNA3Ig κDTA or pcDNA3Ig κLacZ plasmids.These plasmids were transfected into Ig κ producing or non-producing cells by the liposome-coated DNA method.Expression of β-gal activity and effects on cell growth of transfected cells were assessed.Results The β-gal gene, under the control of cytomegalovirus (CMV) promoter, can express in all cell lines.Expression of β-gal under the control of the Ig κ promoter was detected only in the Ig κ producing cell line, CA46.Expression of β-gal was greatly suppressed when cotransfected with pcDNA3Ig κDTA in CA46 cells.Cell growth of CA46 cells transfected with pcDNA3Ig κDTA plasmid was significantly inhibited compared with CA46 cells transfected with pcDNA3Ig κLacZ.Conclusion Selective killing of Ig κ producing cells can be attained by introducing the diphtheria toxin A gene under the control of Ig κ promoter and enhancer.     

Anthrax toxin receptor proteins

Anthrax toxin is a key virulence factor for Bacillus anthracis, the causative agent of anthrax. Here we discuss what is known about the anthrax toxin receptor (ATR), the cellular receptor for anthrax toxin, and how this information is being used to develop treatments for anthrax as well as to understand aspects of cancer. ATR was identified recently as a type I transmembrane protein with unknown function that contains an extracellular integrin-like inserted (I) domain. The ATR I domain contains the toxin binding site, and a soluble form of this domain was shown to serve as an effective antitoxin to protect cultured cells from toxin action. ATR is encoded by the tumor endothelial marker 8 (TEM8) gene, which is selectively up-regulated during blood vessel formation and in tumor vasculature, raising the possibility that this protein normally functions in angiogenesis. Therefore, identification of the cellular receptor for anthrax toxin has made possible new avenues of research in the areas of anthrax pathogenesis, antitoxin development, and cancer biology.     

Learning and sexual deficiencies in transgenic mice carrying a chimeric vasoactive intestinal peptide gene

The molecular mechanisms responsible for behavior are largely unknown. A state of the art model, paving the path from genes to behavior, is offered by transgenic animals. Candidate molecules are classic neuropeptides, such as vasoactive intestinal peptide (VIP). Transgenic mice harboring a chimeric VIP gene driven by the polyoma promoter were produced. Behavioral studies revealed learning impairment and prolonged retardation in memory acquisition in the genetically altered animals. Furthermore, reduced performance was observed when the male transgenic mice were tested for sexual activity in the presence of receptive females. Surprisingly, radioimmunoassays showed an approx 20% decrease in the VIP content of the transgenic mice brains. To directly assess genetically reduced VIP content as a cause for learning impairment, transgenic mice carrying diphtheria toxia-encoding sequences driven by the rat VIP promoter were created. These animals had reduced brain VIP and exhibited deficiencies in learning abilities, strongly supporting an important neurobiological function for VIP in vivo.     

Alginate Nanoparticles as a Promising Adjuvant and Vaccine Delivery System

During last decades, diphtheria has remained as a serious disease that still outbreaks and can occur worldwide. Recently, new vaccine delivery systems have been developed by using the biodegradable and biocompatible polymers such as alginate. Alginate nanoparticles as a carrier with adjuvant and prolong release properties that enhance the immunogenicity of vaccines. In this study diphtheria toxoid loaded nanoparticles were prepared by ionic gelation technique and characterized with respect to size, zeta potential, morphology, encapsulation efficiency, release profile, and immunogenicity. Appropriate parameters (calcium chloride and sodium alginate concentration, homogenization rate and homogenization time) redounded to the formation of suitable nanoparticles with a mean diameter of 70±0.5 nm. The loading studies of the nanoparticles resulted in high loading capacities (>90%) and subsequent release studies showed prolong profile. The stability and antigenicity of toxoid were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and ouchterlony test and proved that the encapsulation process did not affect the antigenic integrity and activity. Guinea pigs immunized with the diphtheria toxoid-loaded alginate nanoparticles showed highest humoral immune response than conventional vaccine. It is concluded that, with regard to the desirable properties of nanoparticles and high immunogenicity, alginate nanoparticles could be considered as a new promising vaccine delivery and adjuvant system.     

Motivational interviewing for maternal Immunizations: Intervention development

Background and ObjectiveVaccine uptake during pregnancy remains low. Our objectives were to describe 1) development and adaptation of a clinician communication training intervention for maternal immunizations and 2) obstetrics and gynecology (ob-gyn) clinician and staff perspectives on the intervention and fit for the prenatal care context.MethodsDesign of the Motivational Interviewing for Maternal Immunizations (MI4MI) intervention was based on similar communication training interventions for pediatric settings and included presumptive initiation of vaccine recommendations (“You’re due for two vaccines today”) combined with motivational interviewing (MI) for hesitant patients. Interviews and focus group discussions were conducted with ob-gyn clinicians and staff in five Colorado clinics including settings with obstetric physicians, certified nurse midwives (CNMs), and clinician-trainees. Participants were asked about adapting training to the ob-gyn setting and their implementation experiences. Feedback was incorporated through iterative changes to training components.ResultsInterview and focus group discussion results from participants before (n = 3), during (n = 11) and after (n = 25) implementation guided intervention development and adaptation. Three virtual, asynchronous training components were created: a video and two interactive modules. This virtual format was favored due to challenges attending group meetings; however, participants noted opportunities to practice skills through role-play were lacking. Training modules were adapted to include common challenging vaccine conversations and live-action videos. Participants liked interactive training components and use of adult learning strategies. Some participants initially resisted the presumptive approach but later found it useful after applying it in their practices. Overall, participants reported that MI4MI training fit well with the prenatal context and recommended more inclusion of non-clinician staff.ConclusionsMI4MI training was viewed as relevant and useful for ob-gyn clinicians and staff. Suggestions included making training more interactive, and including more complex scenarios and non-clinician staff.     

Primary vaccination in adult patients after allogeneic hematopoietic stem cell transplantation – A single center retrospective efficacy analysis

Allogeneic hematopoietic stem cell transplantation (alloHSCT) results in a loss of humoral immunity and subsequent risk for severe infections. Thus, re-vaccination is required but may fail due to incomplete immune reconstitution. We retrospectively analyzed predictors of immune response to primary vaccination applied according to the EBMT (European Blood and Marrow Transplantation Group) recommendations. Serologic response to vaccination against diphtheria (D), tetanus (T), Bordetella pertussis (aP) and Haemophilus influenzae (Hib) (administrated as combined DTaP-Hib-IPV vaccination) was studied in 84 alloHSCT patients transplanted between 2008 and 2015 (age at alloHSCT: 18.6–70.6 years). All patients with a relapse-free survival of ≥9 months, at least 3 consecutive vaccinations and absence of intravenous immunoglobulin administration within 3 months before and after vaccination met the primary inclusion criteria. Additionally, immunological response to a pneumococcal conjugate vaccine was analyzed in a subgroup of 67 patients. Patients’ characteristics at the time of first vaccination were recorded. Responses were measured as vaccine-specific antibody titers. Regarding DTaP-Hib-IPV vaccination, 89.3% (n = 75) of all patients achieved protective titers to at least 3 of the 4 vaccine components and were thus considered responders. 10.7% (n = 9) of the patients were classified as non-responders with positive immune response to less than 3 components. Highest response was observed for Hib (97.4%), tetanus (95.2%) and pneumococcal vaccination (83.6%) while only 68.3% responded to vaccination against Bordetella pertussis. Significant risk factors for failure of vaccination response included low B cell counts (p < 0.001; cut-off: 0.05 B cells/nl) and low IgG levels (p = 0.026; mean IgG of responders 816 mg/dl vs. 475 mg/dl of non-responders). Further, a trend was observed that prior cGvHD impairs vaccination response as 88.9% of the non-responders but only 54.7% of the responders had prior cGvHD (p = 0.073). The results demonstrate, that the currently proposed vaccination strategy leads to seroprotection in the majority of alloHSCT patients.     

2004年天津市2～17岁人群百日咳、白喉抗体水平监测分析

目的了解天津市百日咳、白喉高危人群免疫水平。方法随机抽取2-17岁8个年龄组的儿童采集有效血样1103份,白喉抗毒素用间接血凝法(IHA)测定,百日咳抗体用微量凝集试验测定,并用 SPSS 11．5对监测结果进行统计学分析。结果 2～17岁的健康人群百日咳凝集抗体阳性率为65．29%,保护率为38．17%,抗体阳性率和 GMT 随年龄的增长而显著下降;白喉抗体保护率均在80．00%以上,平均抗体保护率为87．98%,平均抗毒素为0．12IU/ml,不同年龄组之间抗体保护率及平均抗毒素差异均有统计学意义。结论在继续做好健康人群免疫水平监测的同时,应注重百日咳、白喉的加强免疫工作。     

Systematic review of reporting rates of adverse events following immunization: An international comparison of post-marketing surveillance programs with reference to China

Background

China is the most populous country in the world, with an annual birth cohort of approximately 16 million, requiring an average of 500 million vaccine doses administered annually. In China, over 30 domestic and less than 10 overseas vaccine manufacturers supply over 60 licensed vaccine products, representing a growing vaccine market mainly due to recent additions to the national immunization schedule, but data on post-marketing surveillance for adverse events following immunization (AEFI) are sparse.

Objectives

To compare reporting rates for various categories of AEFI from China with other routine post-marketing surveillance programs internationally.

Methods

Systematic review of published studies reporting rates of AEFI by vaccine, category of reaction and age from post-marketing surveillance systems in English and Chinese languages.

Results

Overall AEFI reporting rates (all vaccines, all ages) in Chinese studies were consistent with those from similar international studies elsewhere, but there was substantial heterogeneity in regional reporting rates in China (range 2.3–37.8/100,000 doses). The highest AEFI reporting rates were for diphtheria–tetanus–pertussis whole-cell (DTwP) and acellular (DTaP) vaccines (range 3.3–181.1/100,000 doses for DTwP; range 3.5–92.6/100,000 doses for DTaP), with higher median rates for DTwP than DTaP, and higher than expected rates for DTaP vaccine. Similar higher rates for DTwP and DTaP containing vaccines, and relatively lower rates for vaccines against hepatitis B virus, poliovirus, and Japanese encephalitis virus were found in China and elsewhere in the world.

Conclusions

Overall AEFI reporting rates in China were consistent with similar post-marketing surveillance systems in other countries. Sources of regional heterogeneity in AEFI reporting rates, and their relationships to differing vaccine manufacturers versus differing surveillance practices, require further exploration.     

Diphtheria antitoxin titres six years after basic immunization of adults

Diphtheria antitoxin titres were analysed in 160 adults (median age 59 years, range 34–70), who completed basic vaccination with three doses of 7.5 Lf or 15 Lf of diphtheria toxoid (D) in a previous vaccination trial in 1987, in serum samples drawn 6 years later. The median titre had decreased from 3.2 IU ml⁻¹ in the post vaccination samples to 0.2 IU ml⁻¹ after 6 years in the 15 Lf group and 0.1 IU ml⁻¹ in the 7.5 Lf group. An antitoxin titre of <0.01 IU ml⁻¹, a level usually considered to give no safe protection, was found in 21/73 (29%) individuals, who had received 7.5 Lf and in 12 of 87 (14%), who received 15 Lf diptheria toxoid (P<0.05). In the orginal study, the vaccinees were enrolled as unimmunized based on their own vaccination histories, but many participants had serological evidence of previous immunization. In the subgroup of 48 truly nonimmune participants, i.e. without prevaccination titres and without booster response after the first injection, 46% (32% in the 15 Lf group and 58% in the 7.5 Lf group) had antitoxin levels of <0.01 IU ml⁻¹ 6 years after basic vaccination. Therefore, individuals who have received basic vaccination with three doses of diphtheria toxoid need at least one booster injection 5–10 years later.