炭疽芽孢杆菌疫苗研究进展

炭疽病是一种人畜共患的烈性传染病.该病由炭疽杆菌所致,传播迅速,潜伏期短,死亡率高.炭疽杆菌在生物武器中占有重要地位.本文简述了现用疫苗及各国正在开发的新疫苗,探讨了疫苗研发的新思路,客观评价了人用炭疽疫苗的安全性及有效性.     

山羊痘灭活疫苗免疫保护试验

将山羊痘GT4-STV42-56种毒在犊牛睾丸细胞上繁殖,收获毒液,用0.1%甲醛溶液灭活,加适量206佐剂,制成山羊痘油佐剂灭活疫苗.将疫苗以不同剂量皮下免疫接种不同种群的山羊.免疫后21 d,用AV40株强毒进行攻毒保护试验.结果显示,免疫剂量达0.5 mL时,疫苗对内蒙绒山羊的保护率为100%,对广西黑山羊的保护率为80%.实验表明,山羊痘灭活疫苗对山羊的免疫效果确实可靠.     

牛病毒性腹泻／粘膜病O系弱毒冻干苗的试验生产和检验报告

１９９２￣１９９４年共试生产牛病毒性腹泻／粘膜病（ＢＶＤ／ＭＤ）Ｏ系细胞培养弱毒冻干苗６０万头份，通过实验室内安全检验、效力检验、无菌检验、水份测定、真空度检验、物理性状检验及在玉树、称多和泽库三个疫病发生严重的县试用，证明《ＢＶＤ／ＭＤＯ系细胞培养弱毒冻干苗制造与检验试行办法》可行，并为制定该苗的制造与检验规程提供了依据。     

Vaccination experiments on pregnant mice with E. coli vaccines prepared from septicaemic and enteropathogenic strains of E. coli

Experiments have been carried out with vaccination of pregnant mice against E. coli, followed by i.p. challenge of the offspring at one week of age.With a septicaemic strain the results were highly significant, and the method is therefore recommendable for testing of vaccines against such strains of E. coli.Results were less clear-cut with enteropathogenic strains of E. coli. However, with mortality rates of 40 to 45 % in baby mice born by non-vaccinated mothers and less than 15 % in baby mice born by vaccinated mothers, the difference in percentage mortality seems sufficient to warrant the use of the method also in the control of vaccines against enteropathogenic E. coli strains.     

Studies on the mechanism of vaccinal immunity to Marek''s disease

Current knowledge of the nature of the antigens and of the host immune responses in vaccinal immunity to Marek's disease is reviewed. It is suggested that a two-step mechanism of resistance operates. The first step involves humoral and cell-mediated responses directed against viral antigens; the second step occurs after challenge with Marek's disease virus and consists of cellmediated responses directed against tumour cells.     

Poxviruses as vaccine vectors

The discovery of Jenner in 1798 founded the science of immunology and eventually led to smallpox eradication from the earth in 1980 after a world-wide vaccination campaign with vaccinia virus (another poxvirus) and paradoxically, despite the eradication of smallpox, there has been an explosion of interest in vaccinia virus in the eighties. This interest has stemmed in part from the application of molecular genetics to clone and express foreign genes from recombinant vaccinia viruses. Vaccinia is also gaining renewed interest due to bioterrorism.

These recombinant viruses have multiple applications in research and vaccinology and led to the development of vectored vaccines, such as the recombinant vaccinia rabies vaccine used to eliminate rabies in Western Europe and, more recently, in the United States. Secondly, alternative poxvirus vectors, such as avipox viruses, were proved to be even safer and efficacious non-replicating vectors (suiciole vectors) when used in non-avian species.     

New gene-based approaches for an AIDS vaccine

Vaccine approaches against AIDS have focused on inducing cellular immune responses, since many studies revealed the role of T cell responses in the control of human immunodeficiency virus or simian immunodeficiency virus (SIV) infections. The experimental infection of rhesus macaques with SIV or chimeric SHIV is routinely used as a model for AIDS. In such models, DNA immunization is a tool to elicit specific T cell responses and to study their protective efficacy. DNA immunogenicity in primates depends on parameters such as level of antigen expression, choice of the antigen among SIV proteins, use of fusion proteins, route of immunization, and addition of adjuvants. Recent results suggest that priming with DNA and boosting with attenuated recombinant viral vectors, each expressing corresponding SIV antigens, leads to improved specific immunity and, in some cases, affords protection against pathogenic challenge. After preclinical evaluations, DNA has entered clinical trials for a therapeutic or prophylactic gene-based AIDS vaccine.     

Comparison of antibody values in sera of pigs vaccinated with a subunit or an attenuated vaccine against classical swine fever

Ten pigs, aged 85 days, were vaccinated with a subunit vaccine containing 32 g of classical swine fever virus glycoprotein E2 (gp E2) (group 1), and a further 10 pigs were vaccinated with a C strain vaccine (10^4±0.15 TCID₅₀/ml), produced by amplification in minipig kidney (MPK) cell culture (group 2). Nine non-vaccinated pigs served as a control group (group 3). Serum samples were collected before (day 0) and at 4, 10, 21 and 28 days after vaccination and were analysed by two commercially available enzyme immunoassays and by a neutralizing peroxidase-linked assay (NPLA). At the same times, peripheral blood was taken for determining the total leukocyte count and the body temperature was taken daily. Antibodies were not detected in serum samples collected before vaccination (day 0), and no side-effects that could be connected with vaccination were observed during the trial. Ten days after vaccination 6/10 pigs vaccinated with the subunit vaccine were seropositive. On days 21 and 28, the ratios of serologically positive to vaccinated pigs were 9/10 and 10/10, respectively. Four of the ten pigs that were vaccinated with the C strain vaccine were positive on day 21 and 9/10 on day 28. However, the results of the NPLA showed that only 4/10 pigs had an antibody titre >1:32 at the end of the trial in both the vaccinated groups, even though the subunit vaccine initiated an earlier and higher level of neutralizing antibodies than the vaccine produced from the C strain. Challenge was performed 28 days after vaccination on four randomly selected pigs from both vaccinated groups. The pigs survived the challenge without showing any clinical signs of classical swine fever (CSF), while two nonvaccinated control pigs died on the 10th and 12th days after infection.     

Immune Responses to Intermediate Strain IBD Vaccine at Different Levels of Maternal Antibody in Broiler Chickens

Tropical Animal Health and Production -     

犬冠状病毒基因疫苗表达载体的构建及其免疫原性研究

以pVAX1为载体首次构建了犬冠状病毒病基因的3种真核表达质粒。首先将犬冠状病毒大熊猫株（CCVDXMV）纤突蛋白（S）、膜蛋白（M）和核蛋白（N）基因进行了克隆和序列测定。将测序后的质粒pTS、pTM和pTN分别双酶切，回收目的基因片段并将其定向克隆到真核表达质粒pVAX1中得到重组质粒pVAXS、pVAXM和pVAXN。将这3种真核表达质粒通过脂质体介导法转染MDCK细胞，通过RT—PCR法进行转录水平的检测，并用间接ELISA法检测目的蛋白的表达情况。结果在pVAXS、pVAXM、pVAXN转染MDCK细胞36h后就可检测到目的基因的转录；在转染72h后可检测到3种目的蛋白的表达。动物免疫试验表明，3种真核表达载体能有效地诱导机体产生细胞免疫与体液免疫应答，这为CCV基因疫苗的研究奠定了良好的基础。