Western equine encephalomyelitis vaccine produced in chick embryo cell cultures

A method was developed for production of a freeze-dried Western equine encephalomyelitis vaccine from virus propagated in chick embryo cell culture monolayers maintained with a serum-free medium. A sufficient concentration of virus accumulated in the cell culture fluids prior to the occurrence of viral cytopathology to permit the production of a vaccine relatively free from serum and cellular proteins. Inoculation with two mouse ld₅₀ doses of virus per 100 tissue culture cells was found to yield reproducible high virus titers at a convenient harvest time. These harvests were inactivated at 22 C by 0.05% formalin within 48 hr. Potency test results, as measured by the protection of immunized guinea pigs against an intracerebral virus challenge, indicated that the vaccine produced from the virus propagated in cell culture was equal in potency to a lot of whole chick embryo vaccine used to immunize laboratory and field workers subject to a high risk of infection.     

Assessment of newcastle disease vaccination of houbara bustard breeders (Chlamydotis undulata undulata)

The houbara bustard (Chlamydotis undulata undulata) is endangered in North Africa. Through a captive-breeding program established in Morocco by The Emirates Center for Wildlife Propagation, wild populations are being supplemented by the releasing of captive-reared birds. Newcastle disease, which is caused by Newcastle disease virus (NDV; Avian paramyxovirus type 1), can infect houbara bustards and is a significant threat through contact with backyard poultry and possibly wild birds. Three vaccination schedules for Newcastle disease were evaluated by serologic monitoring to assess the efficiency and safety of various types of vaccines (live vs. inactivated), vaccine strains (Hitchner B1 and Clone 30), and administration routes (intranasal vs. injection). We evaluated antibody titers in 211 adult houbara bustards for 10 mo. Antibody titers to NDV in both sera and egg yolks were monitored by hemagglutination inhibition test. The inactivated vaccine provided a high, homogeneous, and durable serologic response in breeders; titers were higher than log2 11 after 4 wk and remained higher than log2 7 after 10 mo. The response to the two live vaccines was similar, and antibody titers did not exceed log2 6 at sero-conversion. Maternally derived antibodies were efficiently transmitted in vitellus, further confirming that offspring of females hyperimmunized with the inactivated vaccine received high titers of maternal antibodies.     

Phase I evaluation of intranasal trivalent inactivated influenza vaccine with nontoxigenic Escherichia coli enterotoxin and novel biovector as mucosal adjuvants, using adult volunteers

Trivalent influenza virus A/Duck/Singapore (H5N3), A/Panama (H3N2), and B/Guandong vaccine preparations were used in a randomized, controlled, dose-ranging phase I study. The vaccines were prepared from highly purified hemagglutinin and neuraminidase from influenza viruses propagated in embryonated chicken eggs and inactivated with formaldehyde. We assigned 100 participants to six vaccine groups, as follows. Three intranasally vaccinated groups received 7.5-microg doses of hemagglutinin from each virus strain with either 3, 10, or 30 microg of heat-labile Escherichia coli enterotoxin (LTK63) and 990 microg of a supramolecular biovector; one intranasally vaccinated group was given 7.5-microg doses of hemagglutinin with 30 microg of LTK63 without the biovector; and another intranasally vaccinated group received saline solution as a placebo. The final group received an intramuscular vaccine containing 15 microg hemagglutinin from each strain with MF59 adjuvant. The immunogenicity of two intranasal doses, delivered by syringe as drops into both nostrils with an interval of 1 week between, was compared with that of two inoculations by intramuscular delivery 3 weeks apart. The intramuscular and intranasal vaccine formulations were both immunogenic but stimulated different limbs of the immune system. The largest increase in circulating antibodies occurred in response to intramuscular vaccination; the largest mucosal immunoglobulin A (IgA) response occurred in response to mucosal vaccination. Current licensing criteria for influenza vaccines in the European Union were satisfied by serum hemagglutination inhibition responses to A/Panama and B/Guandong hemagglutinins given with MF59 adjuvant by injection and to B/Guandong hemagglutinin given intranasally with the highest dose of LTK63 and the biovector. Geometric mean serum antibody titers by hemagglutination inhibition and microneutralization were significantly higher for each virus strain at 3 and 6 weeks in recipients of the intramuscular vaccine than in recipients of the intranasal vaccine. The immunogenicity of the intranasally delivered experimental vaccine varied by influenza virus strain. Mucosal IgA responses to A/Duck/Singapore (H5N3), A/Panama (H3N2), and B/Guandong were highest in participants given 30 microg LTK63 with the biovector, occurring in 7/15 (47%; P=0.0103), 8/15 (53%; P=0.0362), and 14/15 (93%; P=0.0033) participants, respectively, compared to the placebo group. The addition of the biovector to the vaccine given with 30 microg LTK63 enhanced mucosal IgA responses to A/Duck/Singapore (H5N3) (P=0.0491) and B/Guandong (P=0.0028) but not to A/Panama (H3N2). All vaccines were well tolerated.     

Vaccination against canine distemper virus infection in infant ferrets with and without maternal antibody protection, using recombinant attenuated poxvirus vaccines

Canine distemper virus (CDV) infection of ferrets is clinically and immunologically similar to measles, making this a useful model for the human disease. The model was used to determine if parenteral or mucosal immunization of infant ferrets at 3 and 6 weeks of age with attenuated vaccinia virus (NYVAC) or canarypox virus (ALVAC) vaccine strains expressing the CDV hemagglutinin (H) and fusion (F) protein genes (NYVAC-HF and ALVAC-HF) would induce serum neutralizing antibody and protect against challenge infection at 12 weeks of age. Ferrets without maternal antibody that were vaccinated parenterally with NYVAC-HF (n = 5) or ALVAC-HF (n = 4) developed significant neutralizing titers (log(10) inverse mean titer +/- standard deviation of 2.30 +/- 0.12 and 2.20 +/- 0.34, respectively) by the day of challenge, and all survived with no clinical or virologic evidence of infection. Ferrets without maternal antibody that were vaccinated intranasally (i.n.) developed lower neutralizing titers, with NYVAC-HF producing higher titers at challenge (1.11 +/- 0.57 versus 0.40 +/- 0.37, P = 0.02) and a better survival rate (6/7 versus 0/5, P = 0.008) than ALVAC-HF. Ferrets with maternal antibody that were vaccinated parenterally with NYVAC-HF (n = 7) and ALVAC-HF (n = 7) developed significantly higher antibody titers (1.64 +/- 0. 54 and 1.28 +/- 0.40, respectively) than did ferrets immunized with an attenuated CDV vaccine (0.46 +/- 0.59; n = 7) or the recombinant vectors expressing rabies glycoprotein (RG) (0.19 +/- 0.32; n = 8, P = 7 x 10(-6)). The NYVAC vaccine also protected against weight loss, and both the NYVAC and attenuated CDV vaccines protected against the development of some clinical signs of infection, although survival in each of the three vaccine groups was low (one of seven) and not significantly different from the RG controls (none of eight). Combined i.n.-parenteral immunization of ferrets with maternal antibody using NYVAC-HF (n = 9) produced higher titers (1.63 +/- 0. 25) than did i.n. immunization with NYVAC-HF (0.88 +/- 0.36; n = 9) and ALVAC-HF (0.61 +/- 0.43; n = 9, P = 3 x 10(-7)), and survival was also significantly better in the i.n.-parenteral group (3 of 9) than in the other HF-vaccinated animals (none of 18) or in controls immunized with RG (none of 5) (P = 0.0374). Multiple routes were not tested with the ALVAC vaccine. The results suggest that infant ferrets are less responsive to i.n. vaccination than are older ferrets and raises questions about the appropriateness of this route of immunization in infant ferrets or infants of other species.     

Efficacy in Pigs of Inactivated and Live Attenuated Influenza Virus Vaccines against Infection and Transmission of an Emerging H3N2 Similar to the 2011-2012 H3N2v

Vaccines provide a primary means to limit disease but may not be effective at blocking infection and pathogen transmission. The objective of the present study was to evaluate the efficacy of commercial inactivated swine influenza A virus (IAV) vaccines and experimental live attenuated influenza virus (LAIV) vaccines against infection with H3N2 virus and subsequent indirect transmission to naive pigs. The H3N2 virus evaluated was similar to the H3N2v detected in humans during 2011-2012, which was associated with swine contact at agricultural fairs. One commercial vaccine provided partial protection measured by reduced nasal shedding; however, indirect contacts became infected, indicating that the reduction in nasal shedding did not prevent aerosol transmission. One LAIV vaccine provided complete protection, and none of the indirect-contact pigs became infected. Clinical disease was not observed in any group, including nonvaccinated animals, a consistent observation in pigs infected with contemporary reassortant H3N2 swine viruses. Serum hemagglutination inhibition antibody titers against the challenge virus were not predictive of efficacy; titers following vaccination with a LAIV that provided sterilizing immunity were below the level considered protective, yet titers in a commercial vaccine group that was not protected were above that level. While vaccination with currently approved commercial inactivated products did not fully prevent transmission, certain vaccines may provide a benefit by limitating shedding, transmission, and zoonotic spillover of antigenically similar H3N2 viruses at agriculture fairs when administered appropriately and used in conjunction with additional control measures.     

Dietary l-proline supplementation confers immunostimulatory effects on inactivated Pasteurella multocida vaccine immunized mice

This study was conducted to determine the immunostimulatory effect of l-proline on inactivated vaccine immunized mice. Ninety-five female KM mice were randomly divided into five groups: (1) mice received dietary supplementation with 0.4 % l-proline and immunized with inactivated vaccine (V–P group); (2) mice received dietary supplementation with 0.3 % l-alanine (isonitrogenous control) and immunized with inactivated vaccine (V–A group, negative control); (3) mice were immunized with inactivated vaccine with oil adjuvant (V–O group, positive control); (4) mice were immunized with inactivated vaccine with aluminum hydroxide adjuvant (V–H group, positive control); (5) mice immunized with phosphate-buffered saline (control group). All mice were dead in the control group between 36 and 48 h post infection. Mice in the V–P group showed 100 % protection after challenge with P. multocida serotype A (CQ2) at dose of 4.4 × 10⁵ CFU (2LD50). Meanwhile, serum antibody titers in the V–P group were higher than those in the V–A group before infection and those in the V–A and V–O groups at 36 h post infection. Moreover, serum IL-1β levels in the V–P group were lower than those in V–O group. Furthermore, serum GSH-PX levels in the V–P group were higher than those in the V–A and V–O groups. Collectively, dietary proline supplementation confers beneficial immunostimulatory effects in inactivated P. multocida vaccine immunized mice.     

Characterization of antibody responses to combinations of a dengue virus type 2 DNA vaccine and two dengue virus type 2 protein vaccines in rhesus macaques

We evaluated three nonreplicating dengue virus type 2 (DENV-2) vaccines: (i) a DNA vaccine containing the prM-E gene region (D), (ii) a recombinant subunit protein vaccine containing the B domain (i.e., domain III) of the E protein as a fusion with the Escherichia coli maltose-binding protein (R), and (iii) a purified inactivated virus vaccine (P). Groups of four rhesus macaques each were primed once and boosted twice using seven different vaccination regimens. After primary vaccination, enzyme-linked immunosorbent assay (ELISA) antibody levels increased most rapidly for groups inoculated with the P and DP combination, and by 1 month after the second boost, ELISA titers were similar for all groups. The highest plaque reduction neutralization test (PRNT) titers were seen in those groups that received the DR/DR/DR combination (geometric mean titer [GMT], 510), the P/P/P vaccine (GMT, 345), the DP/DP/DP combination (GMT, 287), and the R/R/R vaccine (GMT, 200). The next highest titers were seen in animals that received the D/R/R vaccine (GMT, 186) and the D/P/P vaccine (GMT, 163). Animals that received the D/D/D vaccine had the lowest neutralizing antibody titer (GMT, 49). Both ELISA and PRNT titers declined at variable rates. The only significant protection from viremia was observed in the P-vaccinated animals (mean of 0.5 days), which also showed the highest antibody concentration, including antibodies to NS1, and highest antibody avidity at the time of challenge.     

Comparison of protection from homologous cell-free vs cell-associated SIV challenge afforded by inactivated whole SIV vaccines

This study attempted to determine if SIV vaccines could protect against challenge with peripheral blood mononuclear cells (PBMCs) from an SIV infected rhesus monkey. Mature Macaca mulatta were vaccinated four times with formalin inactivated SIV_mac32H administered in MDP adjuvant (n = 8) or SIV_mac32H ISCOM vaccine (n = 8). Controls included animals vaccinated with measles virus in MDP adjuvant (n = 4) or ISCOM (n = 4) preparations. Of each group, half were challenged intravenously (IV) with ten MID₅₀ of the cell-free SIV_mac32H (11-88) SIV stock and half were challenged with ten MID₃₀ of PBMCs from the SIV_mac32H infected macaque 1XC. All SIV vaccinated animals challenged with the 11-88 cell free stock of SIV_mac32H were protected, whereas only half of the SIV vaccinated monkeys receiving the same infectious dose of the 1XC cell stock were protected.     

Effective vaccine for lassa fever

Lassa fever has been estimated to cause 5,000 deaths annually in West Africa. Recently, war in the zone where Lassa fever is hyperendemic has severely impeded control and treatment. Vaccination is the most viable control measure. There is no correlation between antibody levels and outcome in human patients, and inactivated vaccines produce high titers of antibodies to all viral proteins but do not prevent virus replication and death in nonhuman primates. Accordingly, we vaccinated 44 macaques with vaccinia virus-expressed Lassa virus structural proteins separately and in combination, with the object of inducing a predominantly TH1-type immune response. Following Lassa virus challenge, all unvaccinated animals died (0% survival). Nine of 10 animals vaccinated with all proteins survived (90% survival). Although no animals that received full-length glycoprotein alone had a high titer of antibody, 17 of 19 survived challenge (88%). In contrast, all animals vaccinated with nucleoprotein developed high titers of antibody but 12 of 15 died (20% survival). All animals vaccinated with single glycoproteins, G1 or G2, died, but all those that received both single glycoproteins (G1 plus G2) at separate sites survived, showing that both glycoproteins are independently important in protection. Neither group had demonstrable antibody levels prior to challenge. We demonstrate that in primates, immune responses to epitopes on both glycoproteins are required to protect against lethal challenge with Lassa virus without having untoward side effects and that this protection is likely to be primarily cell mediated. We show that an effective, safe vaccine against Lassa virus can and should be made and that its evaluation for human populations is a matter of humanitarian priority.     

人轮状病毒ZTR-5株灭活疫苗的制备及小鼠血清免疫学评价

目的: 研究人轮状病毒ZTR-5株灭活疫苗的制备及在实验小鼠中的免疫原性评价。方法: 轮状病毒ZTR-5株在MA104细胞上经蚀斑筛选纯化后,获得单一克隆接种至Vero细胞上适应性培养,免疫荧光定量检测病毒的感染性滴度,对收获的病毒液进行离心、超滤、分子筛纯化,甲醛灭活,抗原定量检测Al(OH)₃吸附制备的实验性疫苗。使用不同剂量(8EU、32EU、128EU、256EU)经肌内注射免疫小鼠,共免疫三次,免疫间隔2周。采用间接ELISA法检测血清特异性抗体效价。 结果: 通过蚀斑纯化,筛选得到一株纯化的病毒株ZTR-5纯-1,在Vero细胞上适应性后感染性滴度达7.35logCCID₅₀/ml;大量培养收获的病毒原液滴度为7.57logCCID₅₀/ml,制备获得轮状病毒样品抗原含量为2 560EU/ml;经肌内注射,初次免疫后,所有剂量组动物均获得抗体阳转,阳转率为100%;第一次加强免疫后,各组血清特异性抗体水平均明显增高,免疫剂量为128EU和256EU的两组小鼠血清抗体效价均达1∶10 240;第二次加强免疫后,各剂量组(8EU、32EU、128EU、256EU)血清抗体效价依次达1∶5 120,1∶7 456,1∶14 481.54,1∶14 481.54。 结论:人轮状病毒ZTR-5株可在Vero细胞上稳定增殖,所制备的疫苗具良好免疫原性,用128EU/2次免疫即可获得良好的免疫效果。     

A Trivalent Virus-Like Particle Vaccine Elicits Protective Immune Responses against Seasonal Influenza Strains in Mice and Ferrets

There is need for improved human influenza vaccines, particularly for older adults who are at greatest risk for severe disease, as well as to address the continuous antigenic drift within circulating human subtypes of influenza virus. We have engineered an influenza virus-like particle (VLP) as a new generation vaccine candidate purified from the supernatants of Sf9 insect cells following infection by recombinant baculoviruses to express three influenza virus proteins, hemagglutinin (HA), neuraminidase (NA), and matrix 1 (M1). In this study, a seasonal trivalent VLP vaccine (TVV) formulation, composed of influenza A H1N1 and H3N2 and influenza B VLPs, was evaluated in mice and ferrets for the ability to elicit antigen-specific immune responses. Animals vaccinated with the TVV formulation had hemagglutination-inhibition (HAI) antibody titers against all three homologous influenza virus strains, as well as HAI antibodies against a panel of heterologous influenza viruses. HAI titers elicited by the TVV were statistically similar to HAI titers elicited in animals vaccinated with the corresponding monovalent VLP. Mice vaccinated with the TVV had higher level of influenza specific CD8+ T cell responses than a commercial trivalent inactivated vaccine (TIV). Ferrets vaccinated with the highest dose of the VLP vaccine and then challenged with the homologous H3N2 virus had the lowest titers of replicating virus in nasal washes and showed no signs of disease. Overall, a trivalent VLP vaccine elicits a broad array of immunity and can protect against influenza virus challenge.     

A caprine herpesvirus 1 vaccine adjuvanted with MF59™ protects against vaginal infection and interferes with the establishment of latency in goats

The immunogenicity and the efficacy of a beta-propiolactone-inactivated caprine herpesvirus 1 (CpHV-1) vaccine adjuvanted with MF59™ were tested in goats. Following two subcutaneous immunizations, goats developed high titers of CpHV-1-specific serum and vaginal IgG and high serum virus neutralization (VN) titers. Peripheral blood mononuclear cells (PBMC) stimulated in vitro with inactivated CpHV-1 produced high levels of soluble IFN-gamma and exhibited high frequencies of IFN-gamma producing cells while soluble IL-4 was undetectable. On the other hand, control goats receiving the inactivated CpHV-1 vaccine without adjuvant produced only low serum antibody responses. A vaginal challenge with virulent CpHV-1 was performed in all vaccinated goats and in naïve goats to assess the efficacy of the two vaccines. Vaginal disease was not detected in goats vaccinated with inactivated CpHV-1 plus MF59™ and these animals had undetectable levels of infectious challenge virus in their vaginal washes. Goats vaccinated with inactivated CpHV-1 in the absence of adjuvant exhibited a less severe disease when compared to naïve goats but shed titers of challenge virus that were similar to those of naïve goats. Detection and quantitation of latent CpHV-1 DNA in sacral ganglia in challenged goats revealed that the inactivated CpHV-1 plus MF59™ vaccine was able to significantly reduce the latent viral load when compared either to the naïve goats or to the goats vaccinated with inactivated CpHV-1 in the absence of adjuvant. Thus, a vaccine composed of inactivated CpHV-1 plus MF59™ as adjuvant was strongly immunogenic and induced effective immunity against vaginal CpHV-1 infection in goats.     

流行性出血热(EHF)Ⅱ型(家鼠型)纯化灭活疫苗Ⅰ期临床观察

根据卫生部(91)特申体第02号文,92年完成了Ⅱ型纯化疫苗Ⅰ期临床反应及血清效果观察,免疫程序为0,1,2月,分原倍疫苗组和1∶2稀释组,各免15人,每针次免疫后连续观察3天,结果均无不良反应,仅在注射时稍有微胀痛感。二针次免疫后均能产生较高的免疫抗体:原倍疫苗免疫抗体滴度,ELISA1∶181(GET),PRNT中和抗体≥1∶10;1∶2稀释疫苗,ELISA1∶169(GMT),PRNT≥1∶10。三针次免疫后抗体滴度高于二针次;原倍疫苗,ELISA1∶478(GMT),PRNT1∶10～1∶20;稀释疫苗,ELISA1∶446(GMT),PRNT1∶10～1∶20,但原倍疫苗和稀释疫苗的抗体水平之间无显著性差异。半年后仍保持一定抗体水平。可采用二针次总量2ml免疫。     

Vaccination with an inactivated virulent feline immunodeficiency virus engineered to express high levels of Env

An inactivated virus vaccine was prepared from a pathogenic isolate of feline immunodeficiency virus containing a mutation that eliminated an endocytic sorting signal in the envelope glycoprotein, increasing its expression on virions. Cats immunized with inactivated preparations of this modified virus exhibited strong titers of antibody to Env by enzyme-linked immunosorbent assay. Evidence of protection following challenge demonstrated the potential of this approach to lentiviral vaccination.     

Influenza H5 hemagglutinin DNA primes the antibody response elicited by the live attenuated influenza A/Vietnam/1203/2004 vaccine in ferrets

Priming immunization plays a key role in protecting individuals or populations to influenza viruses that are novel to humans. To identify the most promising vaccine priming strategy, we have evaluated different prime-boost regimens using inactivated, DNA and live attenuated vaccines in ferrets. Live attenuated influenza A/Vietnam/1203/2004 (H5N1) candidate vaccine (LAIV, VN04 ca) primed ferrets efficiently while inactivated H5N1 vaccine could not prime the immune response in seronegative ferrets unless an adjuvant was used. However, the H5 HA DNA vaccine alone was as successful as an adjuvanted inactivated VN04 vaccine in priming the immune response to VN04 ca virus. The serum antibody titers of ferrets primed with H5 HA DNA followed by intranasal vaccination of VN04 ca virus were comparable to that induced by two doses of VN04 ca virus. Both LAIV-LAIV and DNA-LAIV vaccine regimens could induce antibody responses that cross-neutralized antigenically distinct H5N1 virus isolates including A/HongKong/213/2003 (HK03) and prevented nasal infection of HK03 vaccine virus. Thus, H5 HA DNA vaccination may offer an alternative option for pandemic preparedness.     

Antibody production in rats vaccinated with inactivated Sendai virus (author's transl)

Adult male and female rats were inoculated with tween 80-ethylether-formalin-ultraviolet inactivated Sendai virus (Sv-V) and examined for the production of hemagglutination inhibition (HI) antibody. There were no significant differences in the antibody titers between males and females, and among the various routes of inoculation except for the intranasal which was not effective. The antibody became detectable 7 days after a single inoculation with 10(5) HAU of Sv-V. The antibody titer, which had its peak 21 days after the inoculation, persisted for 200 days and declined gradually thereafter. The HI antibody titers were correlated with inoculated Sv-V doses and a predominant booster reaction with the vaccine was observed. Maternal antibodies were detected in sucklings born to dams hyperimmunized with the vaccine. The titers were similar to those of the dams until 3 weeks after birth but declined rapidly after weaning at 4-week-old. The titers of fetuses and neonates before suckling were significantly lower than those of the sucklings.     

汉滩病毒84Fli株DNA疫苗诱导小鼠免疫应答的初步研究

为了加强我国病毒性出血热的防治,本研究将汉滩病毒84Fli株核蛋白S和糖蛋白M编码片段分别克隆至pcDNA3.0载体,构建了pcDNA3/84S和pcDNA3/84M重组质粒,等量混合采用肌肉注射途径免疫C57BL/6小鼠,免疫3次,每次间隔2周,同时与双价出血热病毒灭活疫苗进行对比。ELISA及免疫荧光(IFA)分别检测小鼠血清中汉滩病毒核蛋白及糖蛋白特异性抗体,流式细胞仪和ELISPOT方法分析小鼠免疫后的细胞免疫水平。微量中和试验检测小鼠血清抗体的的中和活性。结果显示,DNA疫苗免疫组C57BL/6小鼠在初次免疫2周后即能检测到汉滩病毒核蛋白与糖蛋白的特异性抗体,与灭活疫苗组相比,重组质粒诱导的抗体滴度高,产生时间早,产生的抗体具有中和活性;同时可诱导产生特异性细胞免疫应答。研究表明,汉滩病毒pcDNA3/84S和pcDNA3/84M重组质粒能有效刺激小鼠产生特异性体液免疫和细胞免疫应答。     

Sensitive Procedure for Detecting Residual Viable Virus in Inactivated Rabies Vaccine

A procedure for testing inactivated rabies vaccines of tissue culture origin for residual viable virus is reported in which the vaccine to be tested is passed in primary hamster kidney cell culture (PHK) before mouse inoculation. In preliminary experiments, titrations of rabies virus in which each dilution was passed in PHK before inoculating mice yielded titers 100 to 10,000 times higher than the titers obtained for the same virus by direct mouse inoculation. This rabies virus amplification procedure was evaluated by testing 18 lots of inactivated rabies vaccine of tissue culture origin. No viable virus was found in these vaccine lots when tested by direct intracerebral inoculation of mice. Eight of these 18 lots were found to contain viable virus, however, when tested by passage in PHK cell culture. The significance of low levels of viable virus in rabies vaccines is discussed. It is recommended that the amplification procedure described in this report be used in the safety testing of rabies vaccines of tissue culture origin and that it be evaluated for use in testing other rabies vaccines of low tissue content.     

Inactivated SARS-CoV vaccine prepared from whole virus induces a high level of neutralizing antibodies in BALB/c mice

We tested the ability of inactivated SARS-CoV vaccine to induce neutralizing antibodies in BALB/c mice. The inactivated vaccine was prepared by SARS-CoV virus propagation in Vero cells, with subsequent beta-propiolactone inactivation and Sepharose 4FF column chromatography purification. One hundred forty BALB/c female mice were divided into seven groups of 20 mice each. Of the seven groups, three groups were inoculated with 0.1, 1, and 3 microg of the vaccine without adjuvant while three other groups were inoculated at the same three dosages of vaccine with aluminum hydroxide as adjuvant, respectively. The remaining group was set up as a blank control. Each mouse was inoculated twice at an interval of 3 weeks. One week after the second immunization, mice sera were collected to detect serum neutralizing antibodies. An assay for determining neutralizing antibody titers was developed. The results can be summarized as follows: (1) higher dosages of vaccine induced higher levels of neutralizing antibody titer; (2) the level of neutralizing antibodies induced by the inoculation with aluminum hydroxide adjuvant was slightly higher than that without adjuvant, but the difference was not statistically significant.     

Microneedle Vaccination Elicits Superior Protection and Antibody Response over Intranasal Vaccination against Swine-Origin Influenza A (H1N1) in Mice

Influenza is one of the critical infectious diseases globally and vaccination has been considered as the best way to prevent. In this study, immunogenicity and protection efficacy between intranasal (IN) and microneedle (MN) vaccination was compared using inactivated swine-origin influenza A/H1N1 virus vaccine. Mice were vaccinated by MN or IN administration with 1 μg of inactivated H1N1 virus vaccine. Antigen-specific antibody responses and hemagglutination-inhibition (HI) titers were measured in all immunized sera after immunization. Five weeks after an immunization, a lethal challenge was performed to evaluate the protective efficacy. Furthermore, mice were vaccinated by IN administration with higher dosages (> 1 μg), analyzed in the same manner, and compared with 1 μg-vaccine-coated MN. Significantly higher antigen-specific antibody responses and HI titer were measured in sera in MN group than those in IN group. While 100% protection, slight weight loss, and reduced viral replication were observed in MN group, 0% survival rate were observed in IN group. As vaccine dose for IN vaccination increased, MN-immunized sera showed much higher antigen-specific antibody responses and HI titer than other IN groups. In addition, protective immunity of 1 μg-MN group was similar to those of 20- and 40 μg-IN groups. We conclude that MN vaccination showed more potential immune response and protection than IN vaccination at the same vaccine dosage.