Aeromonas Hydrophila Vaccine Research Articles

Immunoadjuvant potential of Asparagus racemosus ethanolic root extract on protection and immune response of Labeo rohita immunized with inactivated Aeromonas hydrophila vaccine

Immunoadjuvant potential of Asparagus racemosus ethanolic root extract on protection and immune response of Labeo rohita immunized with inactivated Aeromonas hydrophila vaccine

Evaluation of feed utilization, immune response and disease resistance in striped catfish, Pangasianodon hypophthalmus (Sauvage 1878) fed with a novel Aeromonas hydrophila biofilm vaccine

Striped catfish, Pangasianodon hypophthalmus was immunized with Biofilm (BF) and Free cell (FC) of Aeromonas hydrophila vaccine at 1010 CFU g−1 for 20 days and monitored for growth parameters, immune responses and disease resistance up to 60 day post vaccination (dpv). Pangasius catfish in the BF vaccinated group had considerably higher growth and feed utilization than the FC vaccinated and unvaccinated groups (p < 0.05). Biofilm vaccinated group showed a significant increase (p < 0.05) in the mean weight gain (46.91 ± 0.59) than the FC (35.94 ± 0.21) and unvaccinated group (34.92 ± 0.35). The vaccinated fishes were challenged with A. hydrophila at 107 CFU/ml. Significant higher relative percentage survival (RPS) was recorded with BF (84.21 ± 1.49%) compared to that with FC (33.33 ± 1.21%). Polyclonal antibody-based ELISA was used to quantify the antibody titre. BF vaccinated group showed significantly higher antibody titer compared to other treatments (p < 0.05). Moreover, higher haematological parameters recorded in the present study were differentially stimulated by the oral administration of A. hydrophila biofilm vaccine. The mean total protein, albumin, and globulin levels of the BF vaccine groups were significantly higher (p < 0.05) than the mean total protein, albumin, and globulin contents of the unvaccinated group. Furthermore, biochemical stress parameters (SGPT, SGOT) in the vaccinated groups showed an incremental trend in the early days of the experimental period. However, the values were significantly lower (p < 0.05) in the biofilm group on 20 dpv onwards indicating improved health condition. Vaccinated BF fishes showed gut associated lymphoid tissues (GALT) within the laminar propria of mid gut. But in FC group fishes showed less aggregation of lymphoid cells. The unvaccinated control fish had no lymphoid cell aggregation in their intestines. The findings of the current research suggested that biofilm vaccine has the capability to be one of the potential oral vaccines in striped catfish against A. hydrophila infection.

Attenuated Listeria monocytogenes as a Vaccine Vector for the Delivery of OMPW, the Outer Membrane Protein of Aeromonas hydrophila.

Listeria monocytogenes (LM) is a gram-positive facultative intracellular pathogen that could stimulate host to produce inflammatory response, cell-mediated immunity, and humoral immunity. In this study, an attenuated live vector vaccine for Aeromonas hydrophila (AH) named EGDeABdd-dat-ompW was successfully constructed using an attenuated vector named EGDeABdd, in which dal, dat, actA, and inlB genes were deleted from wild-type LM-EGDe. To construct EGDeABdd-dat-ompW, a recombinant plasmid pERL3-dat-ompW obtained by inserting the dat gene from EGDe and outer membrane protein gene ompW from AH into pERL3 plasmid was transformed into EGDeABdd cell. The safety and immunogenicity of EGDeABdd-dat-ompW as an attenuated vector vaccine for delivery of OMPW were assessed through analyzing invasion to Caco-2 cells and mice, cytokine production of macrophagocyte and mouse splenocytes, and T-cell proliferation of mouse splenocytes. Serum titers against AH and the immunoprotective effect of the vaccine to mice were also measured after intravenous injection with vaccine for four times. The results showed that the live vector vaccine EGDeABdd-dat-ompW for AH exhibited high attenuation in invading Caco-2 cells and mice than did EGDe. Real-time PCR (RT-PCR) showed that cytokines (e.g., TNF-α, IL-6, and IL-1β from macrophages; and IL-6 and IFN-γ from mouse splenocytes) had significantly increased after immunization by EGDeABdd-dat-ompW. Meanwhile, the vaccine could induce the production of CD3+CD4+ and CD3+CD8+ T-cell proliferation of mice and generate effective immunoprotection against lethal challenge of 20 × LD50 AH. All these results indicated that the attenuated EGDeABdd-dat could be used as a live vector for the delivery of the exogenous gene, not only possessing safety but also providing high immunogenicity. The successful application in the AH vaccine further showed that it could be used in other fields such as vaccines in cancer or infectious diseases.

Current prospects and challenges in fish vaccine development in India with special reference to Aeromonas hydrophila vaccine

Infectious diseases are adversely affecting aquaculture practices throughout world and Asian countries are no exception. Indian aquaculture practices are facing serious setback due to a variety of infectious agent's which are responsible for severe mortality and morbidity of all the cultured freshwater fish species leading to severe economic losses. The emergence of antibiotic resistant pattern, residual effect and environmental degradation due to indiscriminate use of antibiotics has necessitates the development of suitable alternate prophylaxis measures for better protection. In this regard, vaccine(s) has proved to be an effective strategy against pathogens to improve the fish production. Over the years numerous studies have been conducted to develop vaccine(s) against different pathogens. While most of the efforts are made to develop vaccine against bacterial pathogens especially against Aeromoniasis and Edwardsiellosis, few attempts have also been made against certain other bacterial, parasitic and fungal pathogens as well. Despite various successful experimental attempts, till date no vaccines against any of the pathogens are commercially available for Indian aquaculture. This review principally focuses on the current state of art in the development of vaccine against different microbial pathogens in general and Aeromonas hydrophila in particular since the bacterium is a major pathogen which is involved in a number of disease conditions in all the cultured fish species in India. Herein in this review, details of various experimental approaches made to find out a potential vaccine candidate which in turn can induce protective immune responses in host alongwith the constraints associated with it in developing a suitable vaccine against this bacterium and its market potential have been illustrated from an Indian perspective.

The Effectiveness of Vaccines in Gurame (Osphronemus goramy) and Challenged Aeromonas hydrophila

Gurame (Osphronemus goramy) is one of the most commodities cultivated by the people in Indonesia, but there is a production constraint due to gurame that attacked Motile Aeromonas Septicemia (MAS) disease caused by Aeromonas hyrdophila. One of the most effective precautions that can be used is vaccination. Based on the above description, it is necessary to research the effectiveness of Aeromonas hydrophila vaccine in gurame. This research aims to determine the effect of Aeromonas hydrophila vaccine and the amount of bacterial density in an effective vaccine for preventing MAS on gurame (Osphronemus goramy). This study used an experimental method with a complete lyrandomized design consisting of 5 treatments and 4 replications. Parameters observed were survival rate (SR) and antibody titre of carp. The results of this research indicate that giving Aeromonas hydrophila vaccine to gurame can give an effect for increasing the antibody titer and survival rate (SR). The results showed that the amount of 104 CFU/ml of bacterial density in the Aeromonas hydrophila vaccine was the effective vaccine density used as the MAS prevention and showed a high survival rate of 95%. The conclusion of this research is by giving Aeromonas vaccine can prevent MAS and the density of Aeromonas hydrophila vaccine 104 CFU/ml.

Hematological parameters of Catfish (Clarias sp) vaccinated by Aeromonas hydrophila with different application methods

The study aim was to find the effect of different vaccination application methods on hematological parameters of catfish (Clarias sp). A 107 Aeromonas hydrophila measured by 625 nm wave length of Spectrophotometer was applied on 25 catfish with average weight 15.83 g. The application methods were dipping (1 ml/10 l water) and intramuscular injection (0.1 ml/fish). Hematological parameter measured were hematocrit levels, total leukocytes and phagocytic index. Measurement were conduct on day 0, 21, 23 and 27 after vaccine application. The results showed that hematocrit level on fish with injection method were higher (21.02%) than dipping method (15,05%), total leukocytes on fish with dipping method were higher (3,29 x 104 cells/mm3) than injection method (3,15 x 104 cells/mm3) and phagocytic index on fish with injection were higher (25%) than dipping method (23%). The survival of catfish were also observed, and showed that catfish with injection method have higher survival rate (36%) than dipping method (34%). Aeromonas hydrophila vaccine applied with injection method have shown better immune response on catfish (Clarias sp) hematological parameters than one with dipping method.

The Role of Nigella sativa in improving the immune response of the African Catfish (Clarias gariepinus) to Aeromonas hydrophila Vaccine

The Role of Nigella sativa in improving the immune response of the African Catfish (Clarias gariepinus) to Aeromonas hydrophila Vaccine

Comparison of the adjuvant effect of propolis and Freund on the efficacy of Aeromonas hydrophila vaccine in common carp (Cyprinus carpio)

The success of many vaccines relies on their association with selected adjuvants in order to increase their immunogenicity and ensure long-term protection. Propolis is a natural compounds, are mostly known for their immunostimulatory properties. In this study the adjuvant effects of propolis in combination with formalin-killed A. hydrophila vaccine in Common carp (Cyprinus carpio) were evaluated and compared with Freund’s adjuvant. Three hundred juvenile carp (weighing 50.4 ± 3.2 g) were divided randomly into four groups in triplicates. The fish were intraperitonealy injected with Aeromonas hydrophila bacterin (A.h) in combination with normal saline (Formalin Killed Bacterin, FKB group), Freound (FKB +F group), and Propolis (FKB +P group) respectively. Control group were injected with normal saline. Serum samples were taken from fish in each group every other weeks (days 0, 14, 28 and 42) of experiment and immunological parameters including anti A.h antibody titer, serum lysozyme and antibacterial activity, complement activity, Nitro blue tetrazolium activity and serum total protein and globulin were compared among the groups. At the end of study remind fish in each group were challenged with virulent A. hydrophila and mortality recorded for 10 days and Relative Percentage Survival (RPS) calculated and compared among the groups. Results showed that not only the antibody titer, but none specific immune responses of propolis adjuvanted groups was significantly higher than the control group (P 0.05). According to results and based on the effect of propolis on specific (Ab titer), none specific immune response and protection rate (RPS) of common carp against A.hydrophila vaccine, it can be concluded that although propolis as an adjuvant can promote some immune responses of common carp, it can't affect efficacy of vaccine and Ab titer of injected antigens, so it seems more work needs to present propolis as a proper candidate for development of a natural adjuvant in fish vaccines.

The use of coated and uncoated oral inactivated Aeromonas hydrophila vaccine on the immune response of Nile Tilapia (Oreochromis niloticus)

The use of coated and uncoated oral inactivated Aeromonas hydrophila vaccine on the immune response of Nile Tilapia (Oreochromis niloticus)

English

This work aimed to investigate the role of some immunostimulants and probiotics in improving the response of overwintered tilapia to Aeromonas hydrophila vaccine. In this study, 15000 Nile tilapia fry (Orechromis niloticus) were collected and divided into five groups. Group 1 was the control, groups 2 to 5 were fed diet supplemented with garlic, Echinacea, Organic GreenTM and Vet-YeastTM respectively for 5 months. Vaccination with A. hydrophila bacteria was done by the end of the feeding experiment. The antibody titer of the vaccinated overwintered tilapia of all groups showed no significant changes during the same sampling time. A significant high value in the antibody titer was recognized in vaccinated overwintered tilapia at the end of 6th-8th week post-vaccination (PV) in the control group and between the 4th – 8th week PV in the immunostimulant supplemented groups (Groups 2-3), and between the 2nd – 10th week PV in probiotic supplemented groups (Groups 4 and 5). The challenge infection of the vaccinated tilapia showed the highest mortality in Group 1 while the lowest mortality was seen in Group 5. However, maximum protection after challenge was seen at 6th week PV in other treated groups. The immunostimulants and probiotics under test proved efficient in improving the immune response to vaccination which will improve the resistance of tilapia fry against infection during the winter. The overall results are promising to implement overwintering fry culture program to economically maximize and efficiently use the available aquaculture facilities throughout the year. Key words: Tilapia, overwintering, immunostimulants, probiotics, vaccines, pathogens.

Effect of a new recombinant Aeromonas hydrophila vaccine on the grass carp intestinal microbiota and correlations with immunological responses

Intestinal microbiota has become an integral component of the fish, and plays a key role in host metabolism, immunity and health maintenance. However, information on the immune responses after vaccine administration in relation to the intestinal microbiota is absent in fish. The present study focused on the effect of a new recombinant Aeromonas hydrophila vaccine (Aera) by using a novel functionalized, single-walled carbon nanotubes (SWCNTs) as a delivery vehicle on the intestinal microbiota of grass carp (Ctenopharyngodon idella) through the bath immunization, and further explored the immunological responses in intestine, kidney and spleen. By performing deep sequencing, a total of 81,979 valid reads and 609 OTUs obtained from 4 intestine samples were analyzed. We detected 141 genuses, most of which belonged to Firmicutes, Fusobacteria and Proteobacteria. Of note, the quantity of Aeromonas in library Aera (after 6 h Aera vaccine pretreatment, fish were transferred to tanks without SWCNTs-Aera for 28 d) and Aera-GD (6 h Aera vaccine pretreated prior to the group injected by A. hydrophila) was declined 6.5% and 14.6% compared with the control, respectively. Moreover, the expression of seven immune-related genes (IFN-I, TNF-α, CRP, IL-8, IgM, MHC I and CD8α) in the intestine, kidney and spleen of Aera treated fish was significantly enhanced, which indicated that a better tissue immune response in grass carp was induced by the SWCNTs-Aera vaccine. Therefore, a new recombinant SWCNT-Aera vaccine may represent potentially efficient and immunological role in grass carp intestine to resist A. hydrophila infection.

Single-walled carbon nanotubes as delivery vehicles enhance the immunoprotective effects of a recombinant vaccine against Aeromonas hydrophila

To reduce the economic losses caused by diseases in aquaculture industry, more efficient and economic prophylactic measures should be urgently investigated. In this research, the effects of a novel functionalized single-walled carbon nanotubes (SWCNTs) applied as a delivery vehicle for recombinant Aeromonas hydrophila vaccine administration via bath or injection in juvenile grass carp were studied. The results showed that SWCNT as a vector for the recombinant protein aerA, augmented the production of specific antibodies, apparently stimulated the induction of immune-related genes, and induced higher level of survival rate compared with free aerA subunit vaccine. Furthermore, we compared the routes of bath and intramuscular injection immunization by SWCNTs-aerA vaccine, and found that similar antibody levels induced by SWCNTs-aerA were observed in both immunization routes. Meanwhile, a similar relative percentage survival (approximately 80%) was found in both a 40 mg/L bath immunization group, and a 20 μg injection group. The results indicate that functionalized SWCNTs could be a promising delivery vehicle to potentiate the immune response of recombinant vaccines, and might be used to vaccinate juvenile fish by bath administration method.

The efficacy of three mycotoxin adsorbents to alleviate aflatoxin B1-induced toxicity in Oreochromis niloticus

Aflatoxicosis, toxicity of aflatoxin, is of great concern in aquaculture. This study was conducted to assess the efficacies of three adsorbents, a hydrated sodium calcium aluminosilicates (HSCAS), Saccharomyces cerevisiae (S.C.) and an esterified glucomannan (EGM), against feed contaminated with contained 200 μg/kg (ppb) aflatoxin B1 (AFB1). A total of 240 Nile tilapia fingerlings, Oreochromis niloticus (15 ± 2 g), were randomly divided into eight experimental groups (30 fish per group) with three replicates. Group T1 represented the negative control fed on a basal diet, and T2 was the positive control group fed on a basal diet supplemented with 200 ppb AFB1. Groups T3, T4 and T5 were fed the AFB1-contaminated diet (200 ppb) supplemented with 0.5 % HSCAS, 0.25 % S.C or 0.25 % EGM, respectively. Groups T6, T7 and T8 were fed a basal diet supplemented with 0.5 % HSCAS, 0.25 % S.C or 0.25 % EGM, respectively. The reduction in AFB1-bioavailability was judged by toxin residues in fish musculature throughout the study beginning at the second week of exposure. AFB1 reduced the survivability, total weight gain, average daily gain and specific growth rate, evident as early as the second week of exposure. The total erythrocyte count, hemoglobin content and total leukocyte count were significantly decreased after AFB1 exposure for 6, 8 and 10 weeks, respectively. Prolonged administration of AFB1 led to significant increases in serum alanine transaminase, aspartate transaminase and creatinine activity, and produced significant decreases in plasma proteins, including serum globulin. The specific immune response was assessed by an agglutinating antibody titer after immunization of the fish with an Aeromonas hydrophila vaccine. The antibody titer and relative level of protection of fish challenged with Aeromonas hydrophila were reduced throughout the period of examination in AFB1-exposed fish. Supplementation with HSCAS, S.C. or EGM significantly improved growth performance, blood parameters and immune status; in addition, these groups showed decreased AFB1 residues in fish musculature when compared with AFB1-treated fish. HSCAS effectively reduced AFB1 toxicity, whereas S.C. and EGM were less efficacious.

Biochemical and molecular characterization of the novobiocin and rifampicin resistant Aeromonas hydrophila vaccine strain AL09-71N+R compared to its virulent parent strain AL09-71

To understand the fitness cost of novobiocin- and rifampicin-resistance in an attenuated Aeromonas hydrophiila vaccine strain AL09-71 N+R compared to its virulent parent strain AL09-71, colony size, cell size, cell proliferation rate, chemotactic response, and the ability to invade catfish gill cells of the two strains were compared. Our results revealed that: (1) the cell size and the colony size of AL09-71 N+R was significantly (P<0.05) smaller than that of AL09-71; (2) the proliferation rate of AL09-71 N+R was significantly (P<0.05) slower than that of AL09-71; (3) AL09-71 N+R had a significantly (P<0.05) lower chemotactic response to catfish mucus than that of AL09-71; 4) the ability of AL09-71 N+R to invade catfish gill cells was significantly (P<0.05) lower than that of AL09-71. To understand whether target site mutation might play a role in antibiotic resistance, novobiocin's target site DNA gyrase subunit B gyrB and rifampicin's target site RNA polymerase subunit B rpoB were sequenced from the two strains. Our results revealed the following five mutations: (1) two missense mutations (CGC to ATC resulting in arginine/R to serine/S; TAC to TGC resulting in tyrosine/Y to cysteine/C) between AL09-71 gyrB and AL09-71 N+R gyrB; (2) three missense mutations (GAC to AAC resulting in aspartic acid/D to asparagine/N; CTG to CCG resulting in leucine/L to proline/P; CTG to CCG resulting in leucine/L to proline/P) between AL09-71 rpoB and AL09-71 N+R rpoB. To determine whether any unique DNA sequences were present in AL09-71 but absent in AL09-71 N+R, PCR-select bacterial genome subtractive hybridization was performed. Of 96 clones selected from the subtractive genomic DNA library, 32 sequences were found. None of the 32 sequences was confirmed to be present in AL09-71 but absent in AL09-71 N+R. At the transcription level, 29 of the 32 genes were found to be expressed greater than 10-fold in AL09-71 N+R compared to that in AL09-71.

Efficiency of Levamisole in Improving the Immune Response of Catfish (Clarias Gariepenus) to Aeromonas Hydrophila Vaccine: Clinico-Pathological Studies

The effect of Levamisole on the immune response of 200 catfish (Clarias gariepenus) was evaluated. Fish were divided into 4 equal groups, reared in a glass aquaria and fed on a basal diet. The 1 st group served as a control. Fish of the 2 nd group was incorporating Levamisole (150mg/kg diet fed-1) for 2 months. The 3 rd and 4 th groups was vaccinated using Aeromonas hydrophila bacterin, at the first day of experiment, but fish of 4 th group was fed on diet containing same dose of levamisole throughout the 2 months of experiment. At 1 st , 3 rd and 5 th week, blood samples were collected from all groups for hematological, immunological and serum biochemistry studies while fish of 2 nd group were subjected to histopathology. Challenge was done to all groups, at thirty day of experiment, through immersion of fish in virulent Aeromonas hydrophila (1g bacterial cells/liter) for 10min, the mortalities recorded and the dead fish used for the bacterial re-isolation. Catfish of 1 st group showed normal values throughout the period of the experiment. Fish of 2 nd group showed activation of melanomacrophages. Hyperplasia of hematopoietic tissue was evident at 3 rd -4 th week. Degenerative changes were mild at 1 st -2 nd week and become prominent at 5 th week. Fish of 3 rd group showed a significant gradual increase of leucocytes, phgocytosis, antibody titer, total protein and globulin, at 1 st -5 th week post-vaccination. Fish of 4 th group showed higher hematological and immunological values than those of 3 rd group. The relative level of protection after the challenge infection was 30, 85 and 90% for the 2 nd , 3 rd and 4 th groups; respectively. The histopathological finding of this experiment showed the safety of the selected dose of levamesol on catfish. The other findings indicate its efficiency as immunostimulant in improving the immune response of catfish to Aeromonas hydrophila vaccine.

Adjuvant effect of mushroom glucan and bovine lactoferrin upon Aeromonas hydrophila vaccination in catla, Catla catla (Hamilton)

Mushroom glucan and bovine lactoferrin (Lf), known for their immunostimulatory potential, were used as adjuvant in conjunction with a formalin-killed Aeromonas hydrophila vaccine in catla, Catla catla. In vitro antigen-specific responsiveness of catla leucocytes and protective responses against experimental challenge with homologous antigen were monitored following immunization. Antigen-specific proliferation, 'macrophage activating factor' (MAF) production and antibody production were significantly higher in fish injected with glucan adjuvanted vaccine. Lf adjuvanted preparations showed a weak proliferative response and MAF production, although the antibody production was significantly higher than the controls. A good degree of protection was achieved with the glucan adjuvanted vaccine. However, in spite of producing significant anti-A. hydrophila antibody, Lf adjuvanted vaccine did not confer any protection following challenge with A. hydrophila. The potential of adjuvanticity of mushroom glucan and bovine Lf in intraperitoneal vaccination is discussed.

The effect of ascogen on the immune response of Tilapia fish to Aeromonas hydrophila vaccine

The effects of feeding ascogen (5 g kg-1 feed) on the humoral and cell-mediate immune response after immunization of tilapia by intramuscular injection (IM) and direct immersion (DI) with formalin killed Aeromonas hydrophila vaccine (FKAHV) were studied. The results showed that ascogen had a marked immunopotentiating effect after IM as well as after DI vaccination. The immunopotentiating effect of ascogen covered both the humoral and cell-mediated immune response. It was manifested by a marked rise in the geometric mean of antibody titres (haemagglutinating units, HAU) at day 70 after vaccination which reached 409·6 ± 62·71 (after IM) and 48.0 ± 10·.12 (after DI) compared to the vaccinated control groups (57·6 ± 6·40 and 11·2 ± 1·96), respectively. In addition, the mitogenic response of lymphocytes obtained from fish fed with ration containing ascogen was significantly stronger than that of lymphocytes isolated from the control group. Supplementation of ascogen before and after vaccination increased the macrophage migration inhibition percent from 14 to 84 days after vaccination. The relative percent survival of challenged fish after IM and DI vaccination was 89·80% and 40·82% in ascogen supplemented groups compared to the vaccinated nontreated control groups where it was 75·51% and 10·20%, respectively.