Attenuation and molecular characterization of fowl adenovirus 8b propagated in a bioreactor and its immunogenicity, efficacy, and virus shedding in broiler chickens.

Background and Aim: Live-attenuated vaccines are the most successful type of vaccine and could be useful in controlling fowl adenovirus (FAdV) 8b infection. This study aimed to attenuate, molecularly characterize, and determine the immunogenicity, efficacy, and challenge virus shedding in broiler chickens. Materials and Methods: The FAdV 8b isolate (UPM08136) was passaged onto chicken embryo liver (CEL) cells until attenuation. We sequenced and analyzed the hexon and fiber genes of the passage isolates. The attenuated bioreactor-passage isolate was inoculated into 1-day-old broiler chickens with (attenuated and inactivated) and without booster groups and challenged. Body weight (BW), liver weight (LW), liver: body weight ratio (LBR), FAdV antibody titers, T-lymphocyte subpopulation in the liver, spleen, and thymus, and challenge virus load and shedding were measured. Results: Typical cytopathic effects with novel genetic changes on CEL cells were observed. The uninoculated control-challenged (UCC) group had significantly lower BW and higher LW and LBR than the inoculated groups. A significantly higher FAdV antibody titer was observed in the challenged non-booster and attenuated booster groups than in the UCC group. T cells in the spleen and thymus of the liver of inoculated chickens were higher than uninoculated control group levels at all-time points and at different times. A significantly higher FAdV challenge virus load was observed in the liver and shedding in the cloaca of UCC chickens than in non-booster chickens. Conclusion: The FAdV 8b isolate was successfully attenuated, safe, and immunogenic. It reduces virus shedding and is effective and recommended as a vaccine against FAdV infection in broiler chickens.

Efficacy, immunogenicity, and virus shedding in broiler chickens inoculated with live attenuated fowl adenovirus serotype 8b propagated a bioreactor.

Background: Fowl adenovirus (FAdV) 8b causes huge economic losses in the poultry industry worldwide. Attenuated FAdV 8b could be useful in preventing FAdV infections globally and scale-up obstacles could be solved by bioreactor technology. Aim: This study was carried out to attenuate the FAdV 8b isolate, propagate it in a bioreactor, molecularly characterize the passage isolates, and determine the immunogenicity, efficacy, and shedding of the virus of chickens. Methods: FAdV serotype 8b (UPM11142) isolate was passaged on chicken embryo liver (CEL) cells until attenuation and propagated in a bioreactor (UPM11142P20B1). Hexon and fiber genes of the isolates were sequenced and analyzed. UPM11142P20B1 was administered to 116-day-old broiler chickens divided into four groups, A (control), B (non-booster), C (booster with UPM11142P20B1), and D (booster with inactivated UPM11142P5B1). Eight chickens from each group were challenged. Body weight (BW) and liver weight (LW), liver: BW ratio (LBR), FAdV antibody titer, T lymphocyte sub-populations in the liver, spleen and thymus; and challenge virus load in the liver and shedding in cloaca were measured at weekly intervals. Results: The isolate caused typical cytopathic effects on CEL cells typical of FAdV. Novel molecular changes in the genes occurred which could be markers for FAdV 8b attenuation. BW, LW, and LBR were similar among groups throughout the trial but the uninoculated control-challenged group (UCC) had significantly higher LBR than the inoculated and challenged groups at 35 dpi. Non-booster group had higher FAdV antibodies at all time points than the uninoculated control group (UCG); and the challenged booster groups had higher titer at 35 dpi than UCC. T lymphocytes increased at different time-points in the liver of inoculated chickens, and in the spleen and thymus as well, and was higher in the organs of inoculated challenged groups than the UCC. There was a significantly higher challenge virus load in the liver and cloaca of UCC chickens than in the non-booster chickens. Conclusion: UPM11142P20B1 was safe, efficacious, significantly reduced shedding, and is recommended as a candidate vaccine in the prevention and control of FAdV 8b infections in broiler chickens.

TaqMan probe-based qPCR method for specific detection and quantification of fowl adenovirus 8b challenge from chickens inoculated with live attenuated or inactivated virus.

Background: Fowl adenovirus (FAdV) 8b and other serotypes cause inclusion body hepatitis (IBH) in chickens. Specific detection of aetiologic serotype in mixed infection and vaccine failure could be difficult. Aim: The objective of this study was to develop a TaqMan probe-based qPCR method for the detection and quantification of the FAdV 8b challenge virus. Methods: Forty-eight broiler chickens inoculated with live attenuated or inactivated FAdV 8b strains at day 1 of age either with or without booster at day 14 post-inoculation were used. The chickens were challenged with a pathogenic strain of FAdV 8b at day 28 of age. Liver and cloacal swabs were collected on days 7 and 14 post-challenge. Primers and probes were designed, specificity confirmed, and used to carry out qPCR amplification. Results: The assay amplified the FAdV DNA challenge virus, but not that of the live attenuated virus. It could detect FAdV 8b DNA as low as 0.001 ng/µl in liver and cloacal swab samples. Copy numbers obtained indicate virus load and shedding. Conclusions: It shows that a selective detection of FAdV 8b within serotype is possible. It can be useful for rapid detection and diagnosis of the disease, virus quantification and differentiation within species, determination of vaccination failure, and efficacy especially the virus load in the target organ and shedding.

Clinical-Epidemiological Pattern of Primary Immunodeficiencies in Malaysia 1987-2006: A 20 year experience in Four Malaysian Hospitals.

AIM OF STUDY: To determine the clinical and epidemiological characteristics of patients seen with primary immunodeficiencies referred at four Malaysian Hospitals between 1987 to 2007. METHODS: Patient data were retrospectively obtained from patient records and supplemented by information from a standardized questionnaires taken at the time of diagnosis from 4 participating hospitals. The completed data were transferred to document records kept by the first author. The diagnoses made were based on criteria set by WHO Scientific Committee 1986. RESULTS: Fifty one (51) patients with completed records satisfied the criteria of primary immunodeficiencies based on WHO Scientific Committee 1986. Predominant Antibody deficiency (40.4%) is the commonest of the class of primary immunodeficiency (based on modified IUIS classification) followed by phagocytic defect (17.3%), combined immunodeficiencies (15.4%) and other cellular immunodeficiencies (11.5%). The commonest clinical presentation is pneumonia (54%) . A positive Family history with a close family relative afflicted was a strong pointer to diagnosis for PID (52.6%) Primary immnodeficiencies are seen in all the major ethnic groups of Malaysia, predominantly among Malays. As observed in other patient registries, diagnostic delay remains the major cause of morbidity and mortality. CONCLUSION: Primary immunodeficiencies is relative rare but is an emerging disease in Malaysia. Creating awareness of the disease, may reveal more cases within the community. It is sufficient to be a health issue in Malaysia as in other developing countries in the future.

Tumour-associated upregulation of the IL-4 receptor complex.

In a previous study we have shown that monoclonal antibody MR6, which we believe recognizes a component of the human IL-4 receptor complex, binds to a wide variety of epithelial tumours. We have now used this reagent to carry out more detailed analysis of tumours of the breast. Our immunohistochemical data indicate that approximately 30% of these tumours show elevated expression of the molecule to which MR6 binds. In addition, three samples of lymphoma were all MR6-positive. Normal breast tissue from the same patients was either negative or weakly positive. Immunoprecipitation and Western blotting analysis with MR6 show that the molecule expressed on tumour cells is indistinguishable from that on normal tissues. It has an apparent molecular weight of 200 kD, but is highly sensitive to proteolysis yielding a molecule of 145 kD. These data raise the possibility that upregulation of the IL-4 receptor complex may be involved in tumourigenesis. In addition, since only a third of tumours are MR6-positive, the antibody may have potential in differential diagnosis.