Vaccine-Induced Linear Epitope-Specific Antibodies to Simian Immunodeficiency Virus SIVmac239 Envelope Are Distinct from Those Induced to the Human Immunodeficiency Virus Type 1 Envelope in Nonhuman Primates.

To evaluate antibody specificities induced by simian immunodeficiency virus (SIV) versus human immunodeficiency virus type 1 (HIV-1) envelope antigens in nonhuman primate (NHP), we profiled binding antibody responses to linear epitopes in NHP studies with HIV-1 or SIV immunogens. We found that, overall, HIV-1 Env IgG responses were dominated by V3, with the notable exception of the responses to the vaccine strain A244 Env that were dominated by V2, whereas the anti-SIVmac239 Env responses were dominated by V2 regardless of the vaccine regimen.

Interleukin-1- and type I interferon-dependent enhanced immunogenicity of an NYVAC-HIV-1 Env-Gag-Pol-Nef vaccine vector with dual deletions of type I and type II interferon-binding proteins.

UNLABELLED: NYVAC, a highly attenuated, replication-restricted poxvirus, is a safe and immunogenic vaccine vector. Deletion of immune evasion genes from the poxvirus genome is an attractive strategy for improving the immunogenic properties of poxviruses. Using systems biology approaches, we describe herein the enhanced immunological profile of NYVAC vectors expressing the HIV-1 clade C env, gag, pol, and nef genes (NYVAC-C) with single or double deletions of genes encoding type I (ΔB19R) or type II (ΔB8R) interferon (IFN)-binding proteins. Transcriptomic analyses of human monocytes infected with NYVAC-C, NYVAC-C with the B19R deletion (NYVAC-C-ΔB19R), or NYVAC-C with B8R and B19R deletions (NYVAC-C-ΔB8RB19R) revealed a concerted upregulation of innate immune pathways (IFN-stimulated genes [ISGs]) of increasing magnitude with NYVAC-C-ΔB19R and NYVAC-C-ΔB8RB19R than with NYVAC-C. Deletion of B8R and B19R resulted in an enhanced activation of IRF3, IRF7, and STAT1 and the robust production of type I IFNs and of ISGs, whose expression was inhibited by anti-type I IFN antibodies. Interestingly, NYVAC-C-ΔB8RB19R induced the production of much higher levels of proinflammatory cytokines (tumor necrosis factor [TNF], interleukin-6 [IL-6], and IL-8) than NYVAC-C or NYVAC-C-ΔB19R as well as a strong inflammasome response (caspase-1 and IL-1β) in infected monocytes. Top network analyses showed that this broad response mediated by the deletion of B8R and B19R was organized around two upregulated gene expression nodes (TNF and IRF7). Consistent with these findings, monocytes infected with NYVAC-C-ΔB8RB19R induced a stronger type I IFN-dependent and IL-1-dependent allogeneic CD4(+) T cell response than monocytes infected with NYVAC-C or NYVAC-C-ΔB19R. Dual deletion of type I and type II IFN immune evasion genes in NYVAC markedly enhanced its immunogenic properties via its induction of the increased expression of type I IFNs and IL-1β and make it an attractive candidate HIV vaccine vector. IMPORTANCE: NYVAC is a replication-deficient poxvirus developed as a vaccine vector against HIV. NYVAC expresses several genes known to impair the host immune defenses by interfering with innate immune receptors, cytokines, or interferons. Given the crucial role played by interferons against viruses, we postulated that targeting the type I and type II decoy receptors used by poxvirus to subvert the host innate immune response would be an attractive approach to improve the immunogenicity of NYVAC vectors. Using systems biology approaches, we report that deletion of type I and type II IFN immune evasion genes in NYVAC poxvirus resulted in the robust expression of type I IFNs and interferon-stimulated genes (ISGs), a strong activation of the inflammasome, and upregulated expression of IL-1β and proinflammatory cytokines. Dual deletion of type I and type II IFN immune evasion genes in NYVAC poxvirus improves its immunogenic profile and makes it an attractive candidate HIV vaccine vector.

Safety of human immunisation with a live-attenuated Mycobacterium tuberculosis vaccine: a randomised, double-blind, controlled phase I trial.

BACKGROUND: Tuberculosis remains one of the world's deadliest transmissible diseases despite widespread use of the BCG vaccine. MTBVAC is a new live tuberculosis vaccine based on genetically attenuated Mycobacterium tuberculosis that expresses most antigens present in human isolates of M tuberculosis. We aimed to compare the safety of MTBVAC with BCG in healthy adult volunteers. METHODS: We did this single-centre, randomised, double-blind, controlled phase 1 study at the Centre Hospitalier Universitaire Vaudois (CHUV; Lausanne, Switzerland). Volunteers were eligible for inclusion if they were aged 18-45 years, clinically healthy, HIV-negative and tuberculosis-negative, and had no history of active tuberculosis, chemoprophylaxis for tuberculosis, or BCG vaccination. Volunteers fulfilling the inclusion criteria were randomly assigned to three cohorts in a dose-escalation manner. Randomisation was done centrally by the CHUV Pharmacy and treatments were masked from the study team and volunteers. As participants were recruited within each cohort, they were randomly assigned 3:1 to receive MTBVAC or BCG. Of the participants allocated MTBVAC, those in the first cohort received 5 × 10(3) colony forming units (CFU) MTBVAC, those in the second cohort received 5 × 10(4) CFU MTBVAC, and those in the third cohort received 5 × 10(5) CFU MTBVAC. In all cohorts, participants assigned to receive BCG were given 5 × 10(5) CFU BCG. Each participant received a single intradermal injection of their assigned vaccine in 0·1 mL sterile water in their non-dominant arm. The primary outcome was safety in all vaccinated participants. Secondary outcomes included whole blood cell-mediated immune response to live MTBVAC and BCG, and interferon γ release assays (IGRA) of peripheral blood mononuclear cells. This trial is registered with ClinicalTrials.gov, number NCT02013245. FINDINGS: Between Jan 23, 2013, and Nov 6, 2013, we enrolled 36 volunteers into three cohorts, each of which consisted of nine participants who received MTBVAC and three who received BCG. 34 volunteers completed the trial. The safety of vaccination with MTBVAC at all doses was similar to that of BCG, and vaccination did not induce any serious adverse events. All individuals were IGRA negative at the end of follow-up (day 210). After whole blood stimulation with live MTBVAC or BCG, MTBVAC was at least as immunogenic as BCG. At the same dose as BCG (5×10(5) CFU), although no statistical significance could be achieved, there were more responders in the MTBVAC group than in the BCG group, with a greater frequency of polyfunctional CD4+ central memory T cells. INTERPRETATION: To our knowledge, MTBVAC is the first live-attenuated M tuberculosis vaccine to reach clinical assessment, showing similar safety to BCG. MTBVAC seemed to be at least as immunogenic as BCG, but the study was not powered to investigate this outcome. Further plans to use more immunogenicity endpoints in a larger number of volunteers (adults and adolescents) are underway, with the aim to thoroughly characterise and potentially distinguish immunogenicity between MTBVAC and BCG in tuberculosis-endemic countries. Combined with an excellent safety profile, these data support advanced clinical development in high-burden tuberculosis endemic countries. FUNDING: Biofabri and Bill & Melinda Gates Foundation through the TuBerculosis Vaccine Initiative (TBVI).

Safety and Immunogenicity of a Recombinant Adenovirus Serotype 35-Vectored HIV-1 Vaccine in Adenovirus Serotype 5 Seronegative and Seropositive Individuals.

BACKGROUND: Recombinant adenovirus serotype 5 (rAd5)-vectored HIV-1 vaccines have not prevented HIV-1 infection or disease and pre-existing Ad5 neutralizing antibodies may limit the clinical utility of Ad5 vectors globally. Using a rare Ad serotype vector, such as Ad35, may circumvent these issues, but there are few data on the safety and immunogenicity of rAd35 directly compared to rAd5 following human vaccination. METHODS: HVTN 077 randomized 192 healthy, HIV-uninfected participants into one of four HIV-1 vaccine/placebo groups: rAd35/rAd5, DNA/rAd5, and DNA/rAd35 in Ad5-seronegative persons; and DNA/rAd35 in Ad5-seropositive persons. All vaccines encoded the HIV-1 EnvA antigen. Antibody and T-cell responses were measured 4 weeks post boost immunization. RESULTS: All vaccines were generally well tolerated and similarly immunogenic. As compared to rAd5, rAd35 was equally potent in boosting HIV-1-specific humoral and cellular immunity and responses were not significantly attenuated in those with baseline Ad5 seropositivity. Like DNA, rAd35 efficiently primed rAd5 boosting. All vaccine regimens tested elicited cross-clade antibody responses, including Env V1/V2-specific IgG responses. CONCLUSIONS: Vaccine antigen delivery by rAd35 is well-tolerated and immunogenic as a prime to rAd5 immunization and as a boost to prior DNA immunization with the homologous insert. Further development of rAd35-vectored prime-boost vaccine regimens is warranted.

Safety and immunogenicity of a chimpanzee adenovirus-vectored Ebola vaccine in healthy adults: a randomised, double-blind, placebo-controlled, dose-finding, phase 1/2a study.

BACKGROUND: The ongoing Ebola outbreak led to accelerated efforts to test vaccine candidates. On the basis of a request by WHO, we aimed to assess the safety and immunogenicity of the monovalent, recombinant, chimpanzee adenovirus type-3 vector-based Ebola Zaire vaccine (ChAd3-EBO-Z). METHODS: We did this randomised, double-blind, placebo-controlled, dose-finding, phase 1/2a trial at the Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. Participants (aged 18-65 years) were randomly assigned (2:2:1), via two computer-generated randomisation lists for individuals potentially deployed in endemic areas and those not deployed, to receive a single intramuscular dose of high-dose vaccine (5 × 10(10) viral particles), low-dose vaccine (2·5 × 10(10) viral particles), or placebo. Deployed participants were allocated to only the vaccine groups. Group allocation was concealed from non-deployed participants, investigators, and outcome assessors. The safety evaluation was not masked for potentially deployed participants, who were therefore not included in the safety analysis for comparison between the vaccine doses and placebo, but were pooled with the non-deployed group to compare immunogenicity. The main objectives were safety and immunogenicity of ChAd3-EBO-Z. We did analysis by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT02289027. FINDINGS: Between Oct 24, 2014, and June 22, 2015, we randomly assigned 120 participants, of whom 18 (15%) were potentially deployed and 102 (85%) were non-deployed, to receive high-dose vaccine (n=49), low-dose vaccine (n=51), or placebo (n=20). Participants were followed up for 6 months. No vaccine-related serious adverse events were reported. We recorded local adverse events in 30 (75%) of 40 participants in the high-dose group, 33 (79%) of 42 participants in the low-dose group, and five (25%) of 20 participants in the placebo group. Fatigue or malaise was the most common systemic adverse event, reported in 25 (62%) participants in the high-dose group, 25 (60%) participants in the low-dose group, and five (25%) participants in the placebo group, followed by headache, reported in 23 (57%), 25 (60%), and three (15%) participants, respectively. Fever occurred 24 h after injection in 12 (30%) participants in the high-dose group and 11 (26%) participants in the low-dose group versus one (5%) participant in the placebo group. Geometric mean concentrations of IgG antibodies against Ebola glycoprotein peaked on day 28 at 51 μg/mL (95% CI 41·1-63·3) in the high-dose group, 44·9 μg/mL (25·8-56·3) in the low-dose group, and 5·2 μg/mL (3·5-7·6) in the placebo group, with respective response rates of 96% (95% CI 85·7-99·5), 96% (86·5-99·5), and 5% (0·1-24·9). Geometric mean concentrations decreased by day 180 to 25·5 μg/mL (95% CI 20·6-31·5) in the high-dose group, 22·1 μg/mL (19·3-28·6) in the low-dose group, and 3·2 μg/mL (2·4-4·9) in the placebo group. 28 (57%) participants given high-dose vaccine and 31 (61%) participants given low-dose vaccine developed glycoprotein-specific CD4 cell responses, and 33 (67%) and 35 (69%), respectively, developed CD8 responses. INTERPRETATION: ChAd3-EBO-Z was safe and well tolerated, although mild to moderate systemic adverse events were common. A single dose was immunogenic in almost all vaccine recipients. Antibody responses were still significantly present at 6 months. There was no significant difference between doses for safety and immunogenicity outcomes. This acceptable safety profile provides a reliable basis to proceed with phase 2 and phase 3 efficacy trials in Africa. FUNDING: Swiss State Secretariat for Education, Research and Innovation (SERI), through the EU Horizon 2020 Research and Innovation Programme.

Travellers' profile, travel patterns and vaccine practices-a 10-year prospective study in a Swiss Travel Clinic.

BACKGROUND: The travel clinic in Lausanne serves a catchment area of 700 000 of inhabitants and provides pre- and post-travel consultations. This study describes the profile of attendees before departure, their travel patterns and the travel clinic practices in terms of vaccination over time. METHODS: We included all pre-travel first consultation data recorded between November 2002 and December 2012 by a custom-made program DIAMM/G. We analysed client profiles, travel characteristics and vaccinations prescribed over time. RESULTS: Sixty-five thousand and forty-six client-trips were recorded. Fifty-one percent clients were female. Mean age was 32 years. In total, 0.1% were aged <1 year and 0.2% ≥80 years. Forty-six percent of travellers had pre-existing medical conditions. Forty-six percent were travelling to Africa, 35% to Asia, 20% to Latin America and 1% (each) to Oceania and Europe; 19% visited more than one country. India was the most common destination (9.6% of travellers) followed by Thailand (8.6%) and Kenya (6.4%). Seventy-three percent of travellers were planning to travel for ≤ 4 weeks. The main reasons for travel were tourism (75%) and visiting friends and relatives (18%). Sixteen percent were backpackers. Pre-travel advice were sought a median of 29 days before departure. Ninety-nine percent received vaccine(s). The most frequently administered vaccines were hepatitis A (53%), tetanus-diphtheria (46%), yellow fever (39%), poliomyelitis (38%) and typhoid fever (30%). CONCLUSIONS: The profile of travel clinic attendees was younger than the general Swiss population. A significant proportion of travellers received vaccinations that are recommended in the routine national programme. These findings highlight the important role of travel clinics to (i) take care of an age group that has little contact with general practitioners and (ii) update vaccination status. The most commonly prescribed travel-related vaccines were for hepatitis A and yellow fever. The question remains to know whether clients do attend travel clinics because of compulsory vaccinations or because of real travel health concern or both.

A human immune data-informed vaccine concept elicits strong and broad T-cell specificities associated with HIV-1 control in mice and macaques

Background: None of the HIV T-cell vaccine candidates that have reached advanced clinical testing have been able to induce protective T cell immunity. A major reason for these failures may have been suboptimal T cell immunogen designs. Methods: To overcome this problem, we used a novel immunogen design approach that is based on functional T cell response data from more than 1,000 HIV-1 clade B and C infected individuals and which aims to direct the T cell response to the most vulnerable sites of HIV-1. Results: Our approach identified 16 regions in Gag, Pol, Vif and Nef that were relatively conserved and predominantly targeted by individuals with reduced viral loads. These regions formed the basis of the HIVACAT T-cell Immunogen (HTI) sequence which is 529 amino acids in length, includes more than 50 optimally defined CD4+ and CD8+ T-cell epitopes restricted by a wide range of HLA class I and II molecules and covers viral sites where mutations led to a dramatic reduction in viral replicative fitness. In both, C57BL/6 mice and Indian rhesus macaques immunized with an HTI-expressing DNA plasmid (DNA.HTI) induced broad and balanced T-cell responses to several segments within Gag, Pol, and Vif. DNA.HTI induced robust CD4+ and CD8+ T cell responses that were increased by a booster vaccination using modified virus Ankara (MVA.HTI), expanding the DNA.HTI induced response to up to 3.2% IFN-γ T-cells in macaques. HTI-specific T cells showed a central and effector memory phenotype with a significant fraction of the IFN-γ+ CD8+ T cells being Granzyme B+ and able to degranulate (CD107a+). Conclusions: These data demonstrate the immunogenicity of a novel HIV-1 T cell vaccine concept that induced broadly balanced responses to vulnerable sites of HIV-1 while avoiding the induction of responses to potential decoy targets that may divert effective T-cell responses towards variable and less protective viral determinants.

Field evaluation of safety during gestation and horizontal spread of a recombinant differential bovine herpesvirus 1 (BoHV-1) vaccine

Bovine herpesvirus type 1 (BoHV-1) is recognized as a major cause of respiratory, reproductive disease and abortion in cattle. Vaccination is widely applied to minimize losses induced by BoHV-1 infections; however, vaccination of dams during pregnancy with modified live virus (MLV) vaccines has been occasionally associated to abortions. We have previously reported the development of a BoHV-1 recombinant virus, constructed with basis on a Brazilian BoHV-1 (Franco et al. 2002a) from which the gene coding for glycoprotein E (gE) was deleted (gE-) by genetic manipulation. Such recombinant has been previously evaluated in its potential as a differential vaccine (gE- vaccine) that allows differentiation between vaccinated and infected animals. Here, in the first part of the present study, the safety of the gE- vaccine during pregnancy was evaluated by the intramuscular inoculation of 10(7.4) tissue culture 50 % infective doses (TCID50) of the virus into 22 pregnant dams (14 BoHV-1 seronegative; 8 seropositive), at different stages of gestation. Other 15 pregnant dams were kept as non-vaccinated controls. No abortions, stillbirths or fetal abnormalities were seen after vaccination. Seroconversion was observed in both groups of previously seronegative vaccinated animals. In the second part of the study, the potential of the gE- vaccine virus to spread among beef cattle under field conditions was examined. Four heifers were inoculated intranasally with a larger amount (10(7,6) TCID50) of the gE- vaccine (to increase chances of transmission) and mixed with other sixteen animals at the same age and body condition, in the same grazing area, at a population density equal to the average cattle farming density within the region (one cattle head per 10,000 m²), for 180 days. All animals were monitored daily for clinical signs. Serum samples were collected on days 0, 30, 60 and 180 post-vaccination. Seroconversion was observed only in vaccinated heifers. These results indicate that, under the conditions of the present study, the gE- vaccine virus did not cause any noticeable harmful effect on pregnant dams and on its offspring and did not spread horizontally among cattle.

Development and evaluation of a recombinant DNA vaccine candidate expressing porcine circovirus 2 structural protein

Porcine circovirus 2 (PCV2) is generally associated with the porcine circovirosis syndrome, which is considered an important disease of swine and has potentially serious economic impact on the swine industry worldwide. This article describes the construction of a recombinant plasmid expressing the PCV2 structural protein and the evaluation of cellular and humoral immune responses produced by this recombinant vaccine in BALB/c mice. The vaccine candidate was obtained and analyzed in vivo, in an effort to determine the ability to induce a specific immune response in mice. DNA was extracted from a Brazilian PCV2 isolate and the gene coding for Cap protein was amplified by PCR and inserted into an expression plasmid. Groups of BALB/c mice were inoculated intra-muscularly and intradermally in a 15-day interval, with 100 µg and 50 µg of the vaccine construct, respectively. Another group was inoculated intramuscularly with 100 µg of empty plasmid, corresponding to the control group. Seroconversion and cellular response in BALB/c mice were compared and used for vaccine evaluation. Seroconversion was analyzed by ELISA. After a series of 3 immunizations the spleen cells of the immunized animals were used to perform lymphocyte proliferation assays. Seroconversion to PCV2 was detected by ELISA in the animals inoculated with the vaccine construct when compared with control groups. Lymphocyte proliferation assays showed a stronger cell proliferation in the inoculated animals compared with the control group. Thus, the vaccine candidate construct demonstrated to be able to induce both humoral and cellular responses in inoculated mice.

Efficacy of a gE-deleted, bovine herpesvirus 1 (BoHV-1) inactivated vaccine

Bovine herpesvirus type 1 (BoHV-1) is recognized as a major cause of economic losses in cattle. Vaccination has been widely applied to minimize losses induced by BoHV-1 infections. We have previously reported the development of a differential BoHV-1 vaccine, based on a recombinant glycoprotein E (gE)-deleted virus (265gE-). In present paper the efficacy of such recombinant was evaluated as an inactivated vaccine. Five BoHV-1 seronegative calves were vaccinated intramuscularly on day 0 and boostered 30 days later with an inactivated, oil adjuvanted vaccine containing an antigenic mass equivalent to 10(7.0) fifty per cent cell culture infectious doses (CCID50) of 265gE-. Three calves were kept as non vaccinated controls. On day 60 post vaccination both vaccinated and controls were challenged with the virulent parental strain. No clinical signs or adverse effects were seen after or during vaccination. After challenge, 2/5 vaccinated calves showed mild clinical signs of infection, whereas all non vaccinated controls displayed intense rhinotracheitis and shed virus for longer and to higher titres than vaccinated calves. Serological responses were detected in all vaccinated animals after the second dose of vaccine, but not on control calves. Following corticosteroid administration in attempting to induce reactivation of the latent infection, no clinical signs were observed in vaccinated calves, whereas non vaccinated controls showed clinical signs of respiratory disease. In view of its immunogenicity and protective effect upon challenge with a virulent BoHV-1, the oil adjuvanted preparation with the inactivated 265gE- recombinant was shown to be suitable for use as a vaccine.

Brazilian avian metapneumovirus subtypes A and B: experimental infection of broilers and evaluation of vaccine efficacy

Avian metapneumovirus (aMPV) is a respiratory pathogen associated with the swollen head syndrome (SHS) in chickens. In Brazil, live aMPV vaccines are currently used, but subtypes A and, mainly subtype B (aMPV/A and aMPV/B) are still circulating. This study was conducted to characterize two Brazilian aMPV isolates (A and B subtypes) of chicken origin. A challenge trial to explore the replication ability of the Brazilian subtypes A and B in chickens was performed. Subsequently, virological protection provided from an aMPV/B vaccine against the same isolates was analyzed. Upon challenge experiment, it was shown by virus isolation and real time PCR that aMPV/B could be detected longer and in higher amounts than aMPV/A. For the protection study, 18 one-day-old chicks were vaccinated and challenged at 21 days of age. Using virus isolation and real time PCR, no aMPV/A was detected in the vaccinated chickens, whereas one vaccinated chicken challenged with the aMPV/B isolate was positive. The results showed that aMPV/B vaccine provided a complete heterologous virological protection, although homologous protection was not complete in one chicken. Although only one aMPV/B positive chicken was detected after homologous vaccination, replication in vaccinated animals might allow the emergence of escape mutants.

Evaluation of a PCR multiplex for detection and differentiation of Mycoplasma synoviae, M. gallisepticum, and M. gallisepticum strain F-vaccine

Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) are the mycoplasma infections of most concern for commercial poultry industry. MG infection is commonly designated as chronic respiratory disease (CRD) of chickens and infections sinusitis of turkeys. MS causes sub clinical upper respiratory infection and tenosynovitis or bursitis in chickens and turkeys. The multiplex PCR was standardized to detect simultaneously the MS, MG field strains and MG F-vaccine strain specific. The generic PCR for detection of any species of Mollicutes Class was performed and compared to the multiplex PCR and to PCR using species-specific primers. A total of 129 avian tracheal swabs were collected from broiler-breeders, layer hens and broilers in seven different farms and were examined by multiplex PCR methods. The system (multiplex PCR) demonstrated to be very rapid, sensitive, and specific. Therefore, the results showed a high prevalence of MS in the flocks examined (27.9%), and indicate that the MS is a recurrent pathogen in Brazilian commercial poultry flocks.

Short duration of neutralizing antibody titers after pre-exposure rabies vaccination with suckling mouse brain vaccine

The human anti-rabies pre-exposure treatment currently used in Brazil, employing a 1-ml dose of suckling mouse brain vaccine (SMBV) administered on days 0, 2, 4 and 28, was compared to an alternative treatment with two 1 ml-doses on day 0, and one 1 ml-dose injected on days 7 and 21. The latter induced higher virus-neutralizing antibody (VNA) titers on day 21. Both Brazilian rabies vaccines produced with PV or CVS rabies virus strains were tested. Two additional volunteer vaccinee groups, receiving the pre-exposure and the abbreviated post-exposure schedules recommended by the WHO using cell-culture vaccine (CCV) produced with PM rabies virus strain, were included as reference. The VNA were measured against both PV and CVS strains on days 21, 42 and 180 by the cell-culture neutralization microtest. The PV-SMBV elicited higher seroconversion rates and VNA by day 21 than the CVS-SMBV. Both, however, failed to induce a long-term immunity, since VNA titers were <0.5 IU/ml on day 180, regardless of the schedule used. Cell-culture vaccine always elicited very high VNA on all days of collection. When serum samples from people receiving mouse brain tissue were titrated against the PV and CVS strains, the VNA obtained were similar, regardless of the vaccinal strain and the virus used in the neutralization test. These results contrast with those obtained with sera from people receiving PM-CCV, whose VNA were significantly higher when tested against the CVS strain.

New vaccine strategies against enterotoxigenic Escherichia coli: II: Enhanced systemic and secreted antibody responses against the CFA/I fimbriae by priming with DNA and boosting with a live recombinant Salmonella vaccine

The induction of systemic (IgG) and mucosal (IgA) antibody responses against the colonization factor I antigen (CFA/I) of enterotoxigenic Escherichia coli (ETEC) was evaluated in mice primed with an intramuscularly delivered CFA/I-encoding DNA vaccine followed by two oral immunizations with a live recombinant Salmonella typhimurium vaccine strain expressing the ETEC antigen. The booster effect induced by the oral immunization was detected two weeks and one year after the administration of the DNA vaccine. The DNA-primed/Salmonella-boosted vaccination regime showed a synergistic effect on the induced CFA/I-specific systemic and secreted antibody levels which could not be attained by either immunization strategy alone. These results suggest that the combined use of DNA vaccines and recombinant Salmonella vaccine strains can be a useful immunization strategy against enteric pathogens.

Comparative sequence analysis of the P-, M- and L-coding region of the measles virus CAM-70 live attenuated vaccine strain

Measles virus is a highly contagious agent which causes a major health problem in developing countries. The viral genomic RNA is single-stranded, nonsegmented and of negative polarity. Many live attenuated vaccines for measles virus have been developed using either the prototype Edmonston strain or other locally isolated measles strains. Despite the diverse geographic origins of the vaccine viruses and the different attenuation methods used, there was remarkable sequence similarity of H, F and N genes among all vaccine strains. CAM-70 is a Japanese measles attenuated vaccine strain widely used in Brazilian children and produced by Bio-Manguinhos since 1982. Previous studies have characterized this vaccine biologically and genomically. Nevertheless, only the F, H and N genes have been sequenced. In the present study we have sequenced the remaining P, M and L genes (approximately 1.6, 1.4 and 6.5 kb, respectively) to complete the genomic characterization of CAM-70 and to assess the extent of genetic relationship between CAM-70 and other current vaccines. These genes were amplified using long-range or standard RT-PCR techniques, and the cDNA was cloned and automatically sequenced using the dideoxy chain-termination method. The sequence analysis comparing previously sequenced genotype A strains with the CAM-70 Bio-Manguinhos strain showed a low divergence among them. However, the CAM-70 strains (CAM-70 Bio-Manguinhos and a recently sequenced CAM-70 submaster seed strain) were assigned to a specific group by phylogenetic analysis using the neighbor-joining method. Information about our product at the genomic level is important for monitoring vaccination campaigns and for future studies of measles virus attenuation.