Recombinant bacterial vector vaccines have been widely used as carriers for the delivery of protective antigens and nucleic acid vaccines to prevent certain infectious diseases because of their ability to induce mucosal immunity, humoral immunity and cellular immunity. However, protective antigens and nucleic acids recombined into bacterial vector vaccines are difficult to be released into host cells because of the presence of bacterial cell wall. Vaccine strains that are residual in animals or livestock products may also cause environmental contamination and spread of the vaccine strains. The effective solution for these problems is to construct an auto-lysis system that can regulate the vaccine strains to grow normally in vitro while lysis in vivo. The lysis systems that have been applied in germs mainly include: the lysis system based on regulated delayed peptidoglycan synthesis, the lysis system based on the regulation of bacteriophage lysis protein and the lysis system based on the toxin-antitoxin system. In addition, a potential lysis system based on bacterial Type Ⅵ Secretion System (T6SS) is also expected to be a new method for the construction of auto-lysis strains. This review will focus on the regulatory mechanisms of these bacterial lysis systems.
Animals ; Antigens, Bacterial ; Bacterial Vaccines ; Vaccines, Attenuated ; Vaccines, DNA

The first 5 lots of Japanese encephalitis vaccines produced from Beijing-1 strain: JB011203, JB021203, JB030104, JB040204 and JB050304 were controlled of quality on chemical components and virus morphology in vaccine, using reference vaccine EJP034A (BIKEN-Japan). The results showed that: TCA-protein was 13.2- 14.5 µg/ml, the reference was 11.1 µg/ml (WHO standard 5-40 µg/ml). The thimerosal content was 82-84 µg/ml, the reference 76,3 µg/ml (WHO standard ≤120 µg/ml). The formaldehyde content was 0.061-0.063 µg/ml, the reference was 2.19 µg/ml (WHO standard ≤100 µg/ml). pH was 7.02-7.04, the reference was 7.10 (WHO stand. 6.8-7.4). The viruses morphology after negative stain were observed on electromicroscope JEM1010 with enlarge x 90.000 and x 150.000. The identical ball form of purified viruses with the intact surface antigen. 5/5 lots were passed the minimum requirements of biological products of WHO.
Japanese Encephalitis Vaccines ; Antigens ; Bacterial

Humans ; Universities ; Vaccines ; Bacterial Infections

Humans ; Universities ; Vaccines ; Bacterial Infections

Pneumonia is the commonest cause of death of children in Papua New Guinea (PNG). At Tari pneumonia is most commonly caused by Streptococcus pneumoniae and Haemophilus influenzae, which set up rapid severe infections in the lungs that require urgent treatment. In rural PNG, however, treatment is often delayed. Penicillin-resistant forms of these bacteria are on the increase. It is therefore important to have another means of protection against this serious disease. This paper describes three field trials of a vaccine against the commonest serotypes of S. pneumoniae found in PNG. The trials show that a pneumococcal vaccine can prevent deaths from uncomplicated acute lower respiratory tract infection in small children and adults. It is likely that the vaccine does this by limiting the replication of bacteria in the lungs and thus limiting their spread to other parts of the body.
Vaccines ; Pneumonia ; g <3> ; limitin ; Bacterial

This study attempts to develop a reference substance for the live bacteria count of Streptococcicosis live vaccines in order to evaluate the validity of live bacterial count in inspection and testing. We prepared a batch of live Streptococcus suis reference substance for live bacterial count, tested their physical property, purity, vacuum degree, remaining moisture, and determined their homogeneity, thermal stability and transportation stability. Moreover, we organized collaborative calibration to assign count values to the reference substance and determine the shelf life of the reference substance in 12 months. The results showed that the physical property, the purity, the remaining moisture and the vacuum degree of the reference substance were all in compliance with the requirements of the Chinese Veterinary Pharmacopoeia. The homogeneity test showed that the coefficient of variation of the count of the reference substance was less than 10%, indicating a good homogeneity. Transportation stability test showed that the reference substance remained active after 72 h transportation in summer and winter with the package of styrofoam boxes and ice packs. Thermal stability test showed that the reference substance could be stored for up to 3 months at -20 °C, or up to 21 days at 4 °C. According to the collaborative calibration, the reference vaccine was assigned a count value range of (8.5-12.1)×107 CFU/ampoule. The shelf life test showed that the reference substance was stable for 12 months when stored at -70 °C. The reference substance could provide a reference for the live bacterial count of Streptococcicosis live vaccines. Moreover, it could also be used as a reference to evaluate the quality of corresponding agar media.
Bacterial Load ; Reference Standards ; Vaccines, Attenuated

In today's medical industry, the range of vaccines that exist for administration in humans represents an eclectic variety of forms and immunologic mechanisms. Namely, these are the live attenuated viruses, inactivated viruses, subunit proteins, and virus-like particles for treating virus-caused diseases, as well as the bacterial-based polysaccharide, protein, and conjugated vaccines. Currently, a new approach to vaccination is being investigated with the concept of DNA vaccines. As an alternative delivery route to enhance the vaccination efficacy, microneedles have been devised to target the rich network of immunologic antigen-presenting cells in the dermis and epidermis layers under the skin. Numerous studies have outlined the parameters of microneedle delivery of a wide range of vaccines, revealing comparable or higher immunogenicity to conventional intramuscular routes, overall level of stability, and dose-sparing advantages. Furthermore, recent mechanism studies have begun to successfully elucidate the biological mechanisms behind microneedle vaccination. This paper describes the current status of microneedle vaccine research.
Antigen-Presenting Cells ; Bacterial Vaccines ; Dermis ; Epidermis ; Humans ; Skin ; Vaccination ; Vaccines ; Vaccines, DNA

This study was undertaken to acquire some information concerning the mechanism for reduction of nitroblue tetrazolium (NBT) dye by neutrophils. Male rabbits weighing more than 2 kilograms were used in this study. The vaccines. The vaccines utilized were bacterial and viral ones such as typhoid, cholera, measles, and mumps vaccines. The histochemical NBT test was carried out using the method by Park et al. With some modification. Vaccines were given the rabbits, and changes were observed in the percentage and number of pseudoeosinophils and NBT-positive pseudoeosils in the peripheral blood. The data obtained thus were discussed and summarized as follow:1. The percentage of the NBT-positive pseudoeosinophils increased in the rabbits to which the bacterial vaccines were given. 2. The percentage of NBT-positive pseudoeosinophils decreased in the rabbits to whick viral vaccines were given. 3. No association was found between the percentage of the NBT-positive pseudoeosinophils and the number of pseudodosinophils following the administeration.
Bacterial Vaccines ; Cholera ; Humans ; Male ; Measles ; Mumps ; Neutrophils ; Nitroblue Tetrazolium* ; Rabbits* ; Typhoid Fever ; Vaccines ; Viral Vaccines

BACKGROUND: Most of the current licensed viral and bacterial vaccines produced in the world are in the state of antigen suspension, and the immunogenicities of the vaccines can be maintained for one to two years at 4 degrees C, but without refrigeration vaccines easily lose their immunogenicities. METHODS: In this study, as an attempt to improve the stability and maintenancee of the immunogenicity of the vaccines at room termperature or at higher temperatures, sucrose, lactose and glucose were added into the leptospira vaccines respectively, and kept at 37 degrees Cfor 1, 3, 5, and 7 days. The vaccines were inoculated twice into Sprague Dawley rats after 7 days' interval and the titers of the antibodies against the antigen of Leptosp ira icterohemorrhagiae in the sera from rats were measured. Results were evaluated by logistic regress analysis (SAS/PC). RESULTS: Sera from rats inoculated with the normal contol vaccine kept at 4 degrees Cfor 7 days showed antibody titers of 1:20 ~80. The vaccine without sugar exposed at 37 degrees Cfor one day nearly lost its immunogenicity. And the vaccine contained sucrose could keep the immunogenicity at least for 7days at 37 degrees C(p=0.001), though the titers were slightly lower than the titer of normal control. Stabilities of lactose and glucose were lower than sucrose. CONCLUSION: Addition of sucrose, lactose and glucose could increase the stability of leptospira vaccine. 7.5% and 10% sucrose in vaccine could maintain the immunogenicity of leptospira vaccine for 7 days at 37 degrees C. This method is expected to be applied to the production of other viral and bacterial vaccines.
Animals ; Antibodies ; Bacterial Vaccines ; Carbohydrates* ; Glucose ; Lactose ; Leptospira* ; Rats ; Rats, Sprague-Dawley ; Refrigeration ; Sucrose ; Vaccines

Objective: To evaluate the immunogenicity of group A+C meningococcal polysaccharide conjugate vaccine in infants under 2 years old. Methods: From March 2017 to June 2018, 1 932 healthy infants in Biyang County, Henan Province, who were not vaccinated with meningococcal meningitis vaccine and whose axillary temperature was ≤37.0 ℃, were recruited as participants. The 3 months and 6-11 months old infants were allocated to the experiment group and the control group in a ratio of 1∶1. Infants aged 12-23 months were allocated to the 1-dose group, the 2-dose group and the control group in a ratio of 1∶1∶1, with 276 infants in each group. The infants in the experiment group were intramuscularly injected with freeze-dried group A+C meningococcal polysaccharide conjugate vaccine to be evaluated, and infants in the control group received intramuscular injection of commercially available freeze-dried group A+C meningococcal conjugate vaccine. The venous blood of infants was collected 30 days before the first dose and after the last dose of inoculation, and the antibody seroconversion of each group was determined and compared. Results: The completion rate of immunogenicity study was 95.2% (1 839/1 932). Before inoculation, there was no statistical difference in the geometric mean titer and positive rate of group A+C antibodies between the experiment group and the control group in 3 months and 6-11 months old infants (all P values >0.05). The geometric mean titers and positive rate of group A antibodies in the 1-dose group were higher than those in the control group (all P values <0.05), but there was no statistical difference between the 2-dose group and the control group (all P values >0.05) in infants aged 12-23 months. After inoculation, the differences (95%CI) in the positive conversion rate of group A+C antibodies between the experiment group and the control group were -0.12% (-6.01%-5.77%) and 0.82% (-4.23%-5.86%) in the 3 months old infants. At the age of 6-11 months, the differences were 6.75% (1.71%-11.79%) and -4.32% (-8.73%-0.08%), respectively. At the age of 12-23 months, the differences were 1.02% (-3.80%-5.83%) and -4.40% (-7.79%- -1.01%) in the 2-dose group and -7.22% (-12.90%- -1.54%) and -18.61% (-23.75%- -13.46%) in the 1-dose group, respectively. The geometric mean titers of group A+C antibodies in the 3 months old infants were 48.50 and 63.12, respectively, which had no significant difference from the control group (43.02 and 57.99, respectively) (both P values <0.05). The geometric mean titers of group A+C antibodies in the 6-11 months and 12-23 months old infants were 84.09 and 92.51 (2-dose group), which were higher than those in the corresponding control group (43.10 and 61.83, respectively) (all P values <0.001). Conclusion: Group A+C meningococcal conjugate vaccine has good immunogenicity in infants under 2 years old.
Humans ; Infant ; Child, Preschool ; Meningococcal Vaccines ; Vaccines, Conjugate ; Vaccination ; Neisseria meningitidis ; Polysaccharides ; Antibodies, Bacterial