Comparable Levels Of Protection Research Articles

Preharvest and Postharvest Applications of a Pomegranate Peel Extract to Control Citrus Fruit Decay During Storage and Shelf Life.

Green and blue molds are the most important postharvest diseases affecting citrus in storage. These diseases are commonly controlled with fungicides, but legislative restrictions, consumer concerns, and the development of resistant strains of the pathogens have increasingly led to the search for alternative methods of control. A pomegranate peel extract (PGE) was very effective in controlling Valencia orange and clementine postharvest rot under commercial conditions. After cold storage and 7 days of shelf life, the incidence of decay on oranges sprayed before harvest with PGE at 12, 6, and 3 g/liter was reduced by 78.9, 76.0, and 64.6%, respectively. Similarly, postharvest dipping treatments with PGE reduced rot by 90.2, 84.3, and 77.6%, respectively. Comparable levels of protection were also achieved on clementines. On both oranges and clementines, the extract provided a significantly higher level of protection compared with imazalil, a fungicide commonly used for postharvest treatments. The high level of efficacy and the consistent results on different fruit species (clementines and oranges) and with different application methods (preharvest and postharvest) were evidence of reliability and flexibility. PGE also showed a strong antimicrobial activity against fungi and bacteria, suggesting its possible use in sanitizers to reduce the microbial contamination of recirculated water in packinghouses. The results of the present study encourage the integration of conventional chemical fungicides and sanitizers with PGE to control citrus postharvest rot.

Comparison of the short-term and long-term efficacies of the Mycoplasma gallisepticum vaccines ts-11 and 6/85

ABSTRACTIn order to compare the short-term efficacies of the live attenuated Mycoplasma gallisepticum (MG) vaccine strains ts-11 and 6/85, four groups of SPF chickens were vaccinated with each of the vaccines using eye drop and aerosol inoculations, and were subsequently challenged with a wild-type MG strain. When administered by the recommended routes (eye drop for ts-11 and fine aerosol for 6/85), both vaccines induced substantial and comparable levels of protection against airsacculitis and tracheitis caused by wild-type MG. The long-term efficacies of the two vaccines administered by the recommended route were also assessed. Serum antibody responses and colonization of the vaccines in the upper respiratory system were monitored at different time points after vaccination, and protective efficacies of the vaccines were evaluated at 36 weeks post vaccination as above. Systemic antibody response following ts-11 eye drop vaccination was initially strong but reduced gradually over time while, in contrast, that to 6/85 spray vaccination was initially weak but increased over time. Kinetics of the antibody response to the vaccines appeared to be correlated with the number of birds harbouring each vaccine in their upper respiratory system throughout the sampling timepoints. Regardless of the levels of serum antibodies or number of birds harbouring the vaccine, both vaccines induced substantial and comparable levels of protection against airsacculitis and tracheitis caused by wild-type MG. Therefore, kinetics of systemic antibody response and persistence in the upper respiratory system varies between vaccine strains; however, the levels of protection may not, at least up to 36 weeks post vaccination.RESEARCH HIGHLIGHTSThe kinetics of systemic antibody response and persistence of the vaccine in the upper respiratory system varies between vaccine strains ts-11 and 6/85.The levels of protection induced by the two vaccines against virulent MG strain challenge are comparable when they are administered by the route recommended by their manufacturers.

Protection against H5N1 by multiple immunizations with seasonal influenza vaccine in mice is correlated with H5 cross-reactive antibodies

BackgroundCurrent seasonal influenza vaccines are believed to confer protection against a narrow range of virus strains. However, their protective ability is commonly estimated based on an in vitro correlate of protection that only considers a subset of anti-influenza antibodies that are typically strain specific, i.e., hemagglutination inhibiting antibodies. Here, we evaluate the breadth of protection induced with a seasonal trivalent influenza vaccine (composition H1N1 A/California/07/09, H3N2 A/Victoria/210/08, B/Brisbane/60/08) against influenza challenge in mice. MethodsBalb/c mice were immunized once, twice, or three times with seasonal influenza vaccine to assess protection against heterosubtypic H5N1 influenza challenge, or homologous H1N1 influenza virus as a control. Passive transfer of immune serum was used to determine the contribution of humoral immunity to protection. ResultsMultiple immunizations with seasonal influenza vaccine induced up to 80% protection against heterosubtypic H5N1 influenza challenge in mice without eliciting detectable H5N1 neutralizing antibodies. Comparable levels of protection were reached by passive transfer of immune serum, and protection was correlated with the titer of vaccine-induced, H5 cross-reactive, non-neutralizing antibodies that are at least in part directed against conserved HA epitopes. ConclusionsHere, we demonstrate that seasonal vaccine has the ability to induce broad serum-mediated protection, and that the mechanism of this protection is different from the vaccine-induced homologous protection.

Standardizing Co-Culture Conditions Between Chronic Lymphocytic Leukemia Cells and Marrow Stromal Cells: Towards a Reliable and Reproducible System to Assess Cell Adhesion-Mediated Drug Resistance

Contact between chronic lymphocytic leukemia (CLL) cells and accessory stromal cells in tissue microenvironments is considered to play a major role in regulating CLL cell survival and disease progression. Stromal cells of various origins and species, and variable stromal-CLL cell ratios have been used in the past to study CLL-stromal cell interactions and to assess cell-adhesion mediated drug resistance (CAM-DR). Because of the heterogeneity of the currently used in vitro systems to study CLL-MSC interactions, and the importance of these co-culture systems for development and testing of novel agents, we tested a panel of murine and human MSC lines for their capacities to support CLL cell survival and CAM-DR, using various CLL-MSC ratios and fludarabine (F-ara-A) to induce CLL cell apoptosis.We tested four murine, non-transformed MSC lines derived from bone marrow: M210B4, KUM4, ST-2 and KUSA-H1. Also, we tested three human transformed cell lines: Stroma-NKtert, derived from bone marrow and immortalized by human telomerase reverse transcriptase (hTERT), UE6E7-T2 derived from bone marrow and transformed with human papilloma viruses (HPV) E6, E7 and hTERT, and UCB408E6E7Tert33 derived from umbilical cord blood and transformed with hTERT and HPV E6, E7. CLL cells were isolated from peripheral blood of untreated patients and each cell line was tested with at least three different patients according to the following protocol: viability of CLL was tested after 24, 48 and 72 hours by flow cytometry after staining with DiOC6 and propidium iodide. The following conditions were assayed on each of the MSC lines: CLL cells in suspension culture, CLL cells in suspension culture with 10 mM F-ara-A, CLL cells in co-culture with MSC, and CLL cells in co-culture with MSC and with 10 mM F-ara-A. Firstly, we performed titration experiments in order to identify the most appropriate ratio between stromal and CLL cells, using CLL-MSC ratios of 5:1, 10:1, 20:1, 50:1 and 100:1. We found a decline in MSC-derived CLL cell protection at the highest ratio of 100:1, suggesting that ratios of 50:1 or lower provide optimal conditions for in vitro assays. Results shown in Table 1 were assayed using a 20:1 ratio and represented relative viabilities when compared to untreated controls (mean±SEM). Regarding the protective effect of different MSC, we found that all MSC lines demonstrated remarkable protection of CLL cells from spontaneous and F-ara-A-induced apoptosis. We also found that stromal cells that had round shape morphology and easily formed confluent monolayer (M210B4, KUSA-H1, Stroma-NKTert) showed more prolonged protective effect in comparison to cell lines with more spindle shaped morphology (ST-2, KUM4, UE6E7-T2). The failure of UE6E7-T2 and UCB408E6E7Tert33 to demonstrate long-term protection of CLL cells could be related to their own sensitivity to F-ara-A. In this comparative study we demonstrated that both murine and human MSC provide substantial and comparable levels of protection from spontaneous and drug-induced apoptosis. CLL:MSC ratios of 50:1 or lower can be considered ideal for co-culture experiments. Further experiments have to be done to determine the levels of MSC-derived protection in a larger series of CLL samples and in different laboratories for validation. Collectively, in these co-culture assays we can study CLL-MSC interactions and CLL drugs under more standardized conditions that may allow us to evaluate the efficacy of new treatments that target the CLL microenvironment.Time points24 hours48 hours72 hours+Flu+ MSC+ MSC +Flu+Flu+ MSC+ MSC +Flu+Flu+MSC+ MSC +FluM210B485.2±2.4117.2±5.0110.5±4.930.8±12.6138.1±9.5113.0±2.25.2±3.1138.1±5.1120.4±3.4ST-293.6±3.099.9±2.6103.1±0.551.6±9.4111.9±2.689.8±8.713.9±6.3112.6±5.787.0±16.4KUM-493.6±3.0106.4±1.8104.2±1.951.6±9.4112.4±2.6100.8±2.813.9±6.3111.8±6.788.5±11.4KUSA-H179.4±7.4125.1±3.7118.2±2.033.9±10.9136.0±3.6107.2±7.011.3±6.1133.6±5.484.9±7.6Stroma-NKTert79.3±7.0118.6±7.0111.0±7.030.5±9.5130.7±9.5115.6±8.07.1±4.3133.0±11.5122.7±9.0UE6E7-T279.3±7.0113.4±3.9109.3±3.030.5±9.5118.4±4.885.0±7.17.1±4.3119.2±6.951.0±10.1UCB408 E6E7Tert3381.5±7.2120.2±5.4111.8±2.736.7±9.4123.7±6.386.7±7.78.5±6.7119.7±6.150.8±13.0Table 1. Flu: fludarabine (10mM/ml), MSC: marrow stromal cells

Vaccination of cattle with Mycobacterium bovis BCG by a combination of systemic and oral routes

Mycobacterium bovis bacille Calmette-Guérin (BCG) vaccine delivered to calves by the subcutaneous (s.c.) or by the oral route in a formulated lipid matrix has been previously shown to induce similar levels of protection against bovine tuberculosis. The current study was aimed at determining whether a combination of delivering BCG by s.c. and oral routes would enhance levels of protection, compared to only one route of vaccination. Forty calves were randomly divided into four groups (10/group). Calves were vaccinated with 10(6)colony forming units (CFU) of BCG Pasteur by the s.c. route or orally with 10(9)CFU BCG incorporated into a lipid formulation. One group received a combination of BCG administered by both the s.c. and oral routes and a non-vaccinated group served as a control. The two groups of calves that received s.c. BCG produced strong IFN-gamma responses in whole blood cultures stimulated with bovine purified protein derivative (PPD) 3 weeks after vaccination. Cattle vaccinated just with oral BCG in a lipid matrix produced a strong IFN-gamma response 8 weeks after vaccination, and peaking at 11 weeks after vaccination. All calves were challenged by the intratracheal route with M. bovis 15 weeks after vaccination and were euthanized and necropsied to assess protection at 17 weeks following challenge. BCG given s.c. or orally induced significant and comparable levels of protection against the virulent challenge. Vaccination of cattle by a combination of s.c./oral routes did not enhance protection beyond that achieved by s.c. or oral vaccination alone. We conclude that vaccination of cattle with BCG by a combination of routes has no beneficial additive effects, compared to a single s.c. administration of BCG or BCG given orally in a lipid formulation.

Poor correlation between BCG vaccination-induced T cell responses and protection against tuberculosis.

Mycobacterium bovis bacille Calmette-Guérin (BCG) is the most widely used live bacterial vaccine. However, limited information is available correlating route and dose of vaccination and induction of specific T cell responses with protection against tuberculosis. We compared efficacy of oral and systemic vaccination and correlated vaccine-induced T cell responses with protection in experimental tuberculosis of mice. After oral and systemic vaccination, we observed profound differences in persistence and dissemination of BCG and frequencies and location of specific IFN-gamma-secreting CD4(+) and CD8(+) T cells. Yet, both vaccination routes caused comparable levels of protection against aerosol challenge with Mycobacterium tuberculosis. Protection correlated best with rapid accumulation of specific CD8(+) T cells in infected tissues of challenged mice. In contrast, specific IFN-gamma production by CD4(+) T cells reflected the load of M. tuberculosis rather than the strength of protection. Our data question the measurement of IFN-gamma secretion by CD4(+) T cells and emphasize the need for new biomarkers for evaluation of tuberculosis vaccine efficacies.

Heterologous Prime-Boost Vaccination with the LACK Antigen Protects against Murine Visceral Leishmaniasis

This study reports the efficacy of a heterologous prime-boost vaccination using DNA and vaccinia viruses (Western Reserve [WR] virus and modified [attenuated] vaccinia virus Ankara [MVA]) expressing the LACK antigen (Leishmania homologue of receptors for activated C kinase) and an intradermal murine infection model employing Leishmania infantum. At 1 month postinfection, vaccinated mice showed high levels of protection in the draining lymph node (240-fold reduction in parasite burden) coupled with significant levels of gamma interferon (20 to 200 ng/ml) and tumor necrosis factor alpha/lymphotoxin (8 to 134 pg/ml). Significant but lower levels of protection (6- to 30-fold) were observed in the spleen and liver. Comparable levels of protection were found for mice boosted with either LACK-WR or LACK-MVA, supporting the use of an attenuated vaccinia virus-based vaccine against human visceral leishmaniasis.

Derivation, safety and efficacy of a Marek's disease vaccine developed from an Australian isolate of very virulent Marek's disease virus

To develop a serotype 1 Marek's disease (MD) vaccine from a very virulent MDV (vvMDV) pathotype and demonstrate safety and efficacy against early challenge with very virulent field strains in the presence of maternal antibody. Strain BH 16 was isolated and attenuated by serial cell culture passage. One of two cloned passages was selected for vaccine development following early laboratory-scale protection trials in commercial birds. Comparative protection trials were carded out on the BH 16 vaccine and on a CVI 988 Rispens vaccine using commercial and SPF chickens. Challenge viruses used were either a low passage strain BH 16 virus, the Woodlands No. 1 strain or MPF 57 strain of MDV. The BH 16 vaccine was back-passaged in SPF chickens six times and virus recovered from the final passage and the original vaccine virus were tested for safety. The immunosuppressive potential of the BH 16 and Rispens vaccines was also assessed in parallel. The BH 16 and Rispens vaccines induced comparable levels of protection when used as monovalent or multivalent vaccines, although protection achieved with the monovalent vaccines was lower. No gross tumour formation was evident in any birds receiving the BH 16 vaccine or bird-passaged virus, although microscopic lesions were present in 2/12 birds that received the bird-passaged virus. In tests for immunosuppression, there was no histological evidence of damage to either the bursa of Fabricius or the thymus. The BH 16 vaccine was shown to be safe and at least as protective as the Rispens vaccine against three highly virulent MD challenge viruses.

Vaccination of mice with gamma-irradiated Schistosoma japonicum cercariae.

gamma-irradiated cercarial vaccines induce high levels of protection in mice against Schistosoma mansoni infection, however, the same has not been well established for S. japonicum. Here we describe vaccination studies in mice with gamma-irradiated S. japonicum cercariae testing the effectiveness of different irradiation doses, number of vaccinations, and mouse strains. In CBA/Ca mice, a single percutaneous exposure to 500 S. japonicum cercariae previously attenuated by 10, 20, 30, 40 or 50 krad gamma-irradiation induced significant, but comparable levels of protection (34-46%) against challenge infection. In a repeat experiment in C57Bl/6 mice, only groups vaccinated with 10 or 20 krad gamma-irradiated cercariae showed statistically significant, but lower levels of resistance (20-24%). Multiple vaccination of CBA/Ca mice with 500 20 krad gamma-irradiated cercariae did not improve the resistance level (40%). Analysis of IgG responses showed no clear correlation between antibody levels and levels of protection. Western blot analysis suggested that recognition of a 200-kDa antigen might be correlated with protection, that antigens of 42 and 50 kDa may be involved in the protection induced by single vaccination, but that different antigens might be protective in single vs multiple vaccinations. Sera from mice vaccinated with gamma-irradiated cercariae recognized many fewer antigens than more protective sera from mice vaccinated with UV-attenuated cercariae. These results suggest that the mouse may not be a suitable host for studies involving gamma-irradiated S. japonicum vaccines.