Bacteriophage-mediated nucleic acid immunisation

Whole bacteriophage lambda particles, containing reporter genes under the control of the cytomegalovirus promoter (P(CMV)), have been used as delivery vehicles for nucleic acid immunisation. Following intramuscular injection of mice with lambda-gt11 containing the gene for hepatitis B surface antigen (HBsAg), anti-HBsAg responses in excess of 150 mIU ml(-1) were detected. When isolated peritoneal macrophages were incubated with whole lambda particles containing the gene for green fluorescent protein (GFP) under the control of P(CMV), GFP antigen was detected on the macrophage surface 8 h later. Results suggested that direct targeting of antigen-presenting cells by bacteriophage 'vaccines' may occur, leading to enhanced immune responses compared to naked DNA delivery. Bacteriophage DNA vaccines offer several advantages: they do not contain antibiotic resistance genes, they offer a large cloning capacity (approximately 15 kb), the DNA is protected from environmental degradation, they offer the potential for oral delivery, and large-scale production is cheap, easy and extremely rapid.     

Integrated control of Boophilus microplus ticks in Cuba based on vaccination with the anti-tick vaccine Gavac TM

Boophilus microplus has developed resistance against a range of chemical acaricides which has stimulated the development of alternative methods such as vaccination against ticks. In Cuba, the Bm86-based recombinant vaccine Gavac^TM has been successfully used in a number of controlled laboratory and field trials in cattle against B. microplus. In this paper, we have evaluated Gavac^TM in a large scale field trial wherein 588,573 dairy cattle were vaccinated with the aim to reduce the number of acaricidal treatments. It was found that the number of acaricidal treatments could be reduced by 87% over a period of 8 years (1995–2003). Prior to the introduction of the vaccine, 54 clinical cases of babesiosis and six fatal cases were reported per 1000 animals. Six years later, the incidence of babesiosis was reduced to 1.9 cases per 1000 cattle and mortality reduced to 0.18 per 1000. The national consumption of acaricides in Cuba could be reduced by 82% after the implementation of the integrated anti-B. microplus control program.     

The development and use of vaccine adjuvants

Interest in vaccine adjuvants is intense and growing, because many of the new subunit vaccine candidates lack sufficient immunogenicity to be clinically useful. In this review, I have emphasized modern vaccine adjuvants injected parenterally, or administered orally, intranasally, or transcutaneously with licensed or experimental vaccines in humans. Every adjuvant has a complex and often multi-factorial immunological mechanism, usually poorly understood in vivo. Many determinants of adjuvanticity exist, and each adjuvanted vaccine is unique. Adjuvant safety is critical and can enhance, retard, or stop development of an adjuvanted vaccine. The choice of an adjuvant often depends upon expensive experimental trial and error, upon cost, and upon commercial availability. Extensive regulatory and administrative support is required to conduct clinical trials of adjuvanted vaccines. Finally, comparative adjuvant trials where one antigen is formulated with different adjuvants and administered by a common protocol to animals and humans can accelerate vaccine development.     

Novel protein vaccine candidates against Group B streptococcal infection identified using alkaline phosphatase fusions

Using an alkaline phosphatase-based genetic screening method, we identified a number of proteins that are potentially located on the outer surface of Group B streptococcus (Streptococcus agalactiae). In an enzyme-linked immunosorbent assay, antisera raised against two of the proteins, the streptococcal yutD homologue and a subunit of an ABC transporter, recognised clinically important serotypes of Group B streptococcus. In a neonatal rat model, purified IgG from the sera conferred significant levels of protection against a lethal challenge infection. The proteins identified show potential as protein subunit candidates for vaccines against Group B streptococcal disease in neonates.     

Vaccines, coming of age after 200 years

An overview on the short, only 200 years, past history and future expectations in the field of vaccines is presented. The focus is on development trends and potential rather than individual vaccines. While the first vaccines were a result of keen observation, the further development has been tightly dependent on the development of microbiology to provide both the knowledge basis and the technology for new vaccines for new purposes. The post-genomic era just starting therefore promises an exponential increase of vaccine research and new vaccines, both improved vaccines with a greater efficacy and less adverse effects to replace old ones and vaccines for prevention of diseases for which no vaccines exist. Furthermore, fully new applications to prevention or treatment of chronic diseases not traditionally associated with infections are expected.     

冻干腮腺炎活疫苗细胞培养生产工艺研究

报告了冻干腮腺炎活疫苗细胞培养生产工艺研究结果,通过对鸡胚疫苗株的适应培养及对细胞培养生产工艺的试验优化,建立了连续细胞培养多次收获疫苗生产工艺并制备出了冻干细胞培养腮腺炎活疫苗制剂。本生产工艺切实可行,生产成本低、投入产出率高,所用原材料规范、质量易于控制,具有明显的技术优势。生产的冻干疫苗制剂质量稳定可靠,符合中国生物制品规程要求,有利于预防腮腺炎的规模化推广使用     

Recent Advances in Design and Synthesis of Self-Adjuvanting Lipopeptide Vaccines

Synthetic lipopeptide vaccines are being increasingly investigated mainly because of the advantages they offer over traditional vaccines, including safety of use in humans, high specificity in eliciting immune responses, greater purity and large scale/cost-effective production capacity. Moreover, a number of lipopeptide vaccines designed to possess self-adjuvanting properties have been developed and tested in vitro and in vivo. Producing high levels of serum-specific antibodies against incorporated peptide epitopes, they are showing their potential as effective vaccine candidates without the need for a co-administered adjuvant and/or carrier protein, often associated with undesirable effects in humans. This review presents recent insights on lipopeptide vaccine research and development, particularly on (1) the influence of the orientation of peptide epitopes and lipids on immune responses, (2) the use of carbohydrates for vaccine targeting, adjuvanting or as peptide epitope carriers, and (3) synthetic approaches to highly pure, multi-epitopic vaccine molecules using native chemical ligation techniques. Incorporation of different types of antigens within the same lipopeptide construct could provide a lipopeptide vaccine candidate suitable for safe and effective mucosal administration, which is a comfortable way of drug delivery.     

Liposome-polycation-DNA (LPD) particle as a carrier and adjuvant for protein-based vaccines: Therapeutic effect against cervical cancer

With the successful identification of many tumor-specific antigens, tumor-associated antigens, and the potential of using unfractioned tumor cell derivatives as tumor antigens, a system and/or adjuvant that can deliver these antigens and help them to induce strong and effective anti-tumor immune responses is greatly needed. Previously, we reported that a MHC class I-restricted peptide epitope derived from human papillomavirus (HPV) 16 E7 protein, when incorporated into a clinically proven safe LPD (liposome-polycation-DNA) particle, was able to effectively eradicate tumors established in mice. Cervical cancer is the second most common cancer among women worldwide. HPV infection is clearly linked to this cancer. Vaccines based on the early (E) gene products of HPV could be effective in controlling it. However, besides the fact that epitope vaccines have many limitations particularly, concerning the diverse HLAs in humans, the use of the epitope as an antigen prevented us from fully characterizing the immune responses induced by the LPD as a vaccine carrier and/or adjuvant in previous studies. In the present study, by using the HPV 16 E7 protein as an antigen, we first showed that LPD, as a vaccine carrier and adjuvant induced strong and robust immune responses, both cellular and antibody. We then showed that immunization with LPD particles incorporated with either the wild type HPV 16 E7 protein or a potentially safer mutant induced strong immune responses that caused complete regressions of a model cervical cancer tumor established in murines. LPD could be a potent vaccine carrier and/or adjuvant for many antigens.     

百日咳杆菌去内毒素及保护性抗原的纯化

内毒素(Endotoxin,简称ET)是百日咳全菌苗(Bordetellapertussis vaccine)产生副作用的主要毒素之一,且不易除去。现有的分离方法,如蔗糖密度梯度离心法,较繁琐,成本高。本文采用Sepha-cryl S-300凝胶层折法可以简便有效的去除大部分内毒素。初步毒素试验结果表明:已达到日本生物制品规格的要求。两种保护性抗原FHA和LPF-HA也得到进一步分离纯化,为今后研制高效的百日咳组分菌苗提供了实验条件。     

用转基因植物生产基因工程疫苗

用转基因植物生产外源蛋白质产品是一个有吸引力的廉价生产系统,它有可能替代外源蛋白质的发酵生产系统。通过外源基因的瞬时表达或稳定表达方式,多种疫苗已在植物中产生,在植物中表达的抗原保持了它自身的免疫原性,植物在这方面的应用具有独特的优 点。