A. Thangavelu

Expression profile of toll like receptors in a range of water buffalo tissues (Bubalus bubalis).

The present study was carried out to determine the expression profile of toll-like receptors (TLRs) 1-10 in buffalo peripheral blood mononuclear cells (PBMNC), neutrophils, spleen, liver, lung, heart, kidney, ovary and uterus using reverse transcriptase polymerase chain reaction (RT-PCR) with bovine TLR-specific primers The buffalo TLR partial nucleotide sequences had 95-98% nucleotide homology with bovine TLR sequences available in the GenBank. PBMNC expressed all TLRs except TLR1 and neutrophils expressed all TLRs except TLR3. Expression of all TLRs was observed in spleen, lung and liver tissues. Wide range of TLR mRNA expression was observed in heart, which lacked the expression of only TLR10. Among the tissues analyzed kidneys had the least repertoire of TLR expression. The kidney tissue revealed mRNA expression of only TLR2, TLR5, TLR7 and TLR9. Among the reproductive tissues analyzed, uterus expressed a wide range of TLRs such as 2, 5, 7, 8, 9 and 10 while ovary expressed all TLRs except TLR1 indicating their immuno competence.

PATHOGENICITY AND IMMUNOSUPPRESSIVE PROPERTIES OF INFECTIOUS BURSAL DISEASE VIRUS FIELD ISOLATES AND COMMERCIAL VACCINES IN INDIA

The pathogenicity and immunosuppressive properties of two field isolates of infectious bursal disease virus (IBDV) and five commercial IBDV live virus vaccines marketed in India were evaluated in this study. The pathogenicity of the wild type viruses and vaccines were based on mortality, the bursa:body weight ratio and microscopic lesions in the bursa in 3-week-old chicks that received these viruses. The immunosuppressive effects of these viruses were evaluated by measuring the antibody responses to sheep red blood cells, Brucella abortus plain antigen and Newcastle disease virus (NDV) vaccine in one-day-old chicks. One field isolate (N35/93) was found to be more pathogenic and immunosuppressive than the other (N45/92) while none of the commercial mild ‘Lukert’ type vaccines were found to be pathogenic. One of the vaccine strains marked as ‘Mild Lukert type’ was highly immunosuppressive; one was moderate and one could be classified as mild. Both the intermediate vaccines tested were highly immunosuppressive.

Quantitative counter-immunoelectrophoresis for estimation of antibodies to infectious bursal disease virus.

Quantitative counter-immunoelectrophoresis was standardized to detect antibodies to the avian infectious bursal disease virus. This technique correlated well with the conventional quantitative agar gel precipitation test in estimating antibodies to IBDV. The use of blood dried on filter paper as an alternative to serum is discussed. QCIE is simple, easy to perform and faster than QAGP.

Immunorheophoresis for the diagnosis of infectious bursal disease.

The immunorheophoresis (IR) technique was used for the detection of infectious bursal disease antigen from bursae collected from field cases and experimentally infected chickens. When these results were compared with that of the agar gel immunodiffusion (AGID) test, they showed excellent agreement as determined by kappa value. However, the time taken for the appearance of the precipitin lines was reduced from 14-24 hr in the AGID test to 3-5 hr in the IR technique.

Evaluation of a filter paper blood sampling technique for quantitative assessment of antibodies to infectious bursal disease virus.

Infectious bursal disease (IBD) is an acute infectious disease of chickens that is manifested either as immunosuppression or as a clinical disease, depending on the age of the birds. Vaccination of commercial chickens becomes essential in endemic areas to protect against clinical disease. The presence of maternal antibodies has been found to interfere with multiplication of IBD live virus vaccines (Cullen and Wyeth, 1975). The timing of vaccination is therefore crucial for successful vaccination programmes. A simple and sensitive quantitative agar gel precipitation (QAGP) test is available to quantify infectious bursal disease virus (IBDV)-speci¢c antibodies (Cullen and Wyeth, 1975). However, large-scale seromonitoring for maternal antibody or for the post-vaccinal immune response is hampered by the problems associated with collection, storage and transport of serum samples to the laboratory. To overcome these di¤culties, sampling blood on ¢lter paper has been recommended for serosurveillance of many diseases (Brugh and Beard, 1980; Rivertz et al., 1985; Roy et al., 1992). Filter paper eluates have been used for IBD serology in place of serum (Roy et al., 1994), with a sensitivity of only 64%. However, a quantitative comparison of QAGP titres between whole serum and corresponding ¢lter paper eluates has not been made. This communication deals with such a comparison using di¡erent elution protocols. Tropical AnimalHealth and Production, 32 (2000) 179^182 # 2000 Kluwer Academic Publishers. Printed in the Netherlands

Rocket immunoelectrophoresis in the diagnosis of infectious bursal disease.

The rocket immunoelectrophoresis (RIE) test was used for the qualitative detection and quantitative estimation of infectious bursal disease virus (IBDV) specific antigen in experimentally infected chickens and samples collected from suspected outbreaks. The IBDV specific antigen was detected in the bursae of experimentally inoculated chickens up to 5 days post infection (PI) by the agar gel precipitation (AGP) test and 7 days PI by the RIE test. The RIE detected IBDV specific antigen in a significantly greater number of samples collected from the field outbreaks than the conventional AGP test. Exudative bursae were found to have a higher antigen content than haemorrhagic bursae and are recommended as the material of choice for diagnosis of IBD. This test could also be used to quantify IBDV specific antigen in commercial killed vaccines.