Bovine Tuberculin Purified Protein Derivative Research Articles

Potential of the dual IFN-γ/IL-2 fluorescence-immunospot assay to distinguish different stages in bovine tuberculosis

Human studies have identified the potential of measuring Mycobacterium tuberculosis specific IFN-γ and/or IL-2 secreting T cell subsets to distinguish different clinical stages of human tuberculosis (TB). To assess these functional T cell subsets in different states of bovine TB we have established a bovine dual IFN-γ/IL-2 fluorescence-immunospot (FluoroSpot) assay and analysed the frequencies of Mycobacterium bovis (M. bovis) specific IL-2 and/or IFN-γ producing cells in PBMC from 30 cattle naturally infected with M. bovis. Depending on their post mortem results the animals were grouped in 22 cattle with visible lesions (VL) and 8 cattle without visible lesions (NVL). In response to bovine tuberculin purified protein derivative (PPD-B) the frequencies of cytokine producing cells and proportions of IL-2 single producers were significantly higher in VL compared to NVL while PWM-induced cytokine responses were similar between the two groups. Dual IL-2+IFN-γ+ T cells could be identified as the largest PPD-B responsive T cell subset in both cattle groups. In conclusion, our FluoroSpot is a valid method to enumerate individual antigen-specific IFN-γ+ and IL-2+ T cell subsets ex vivo. The greater levels of single IL-2 producing T cells associated with the presence of pathology could be a potential biomarker for active TB in cattle.

A New Model to Calibrate a Reference Standard for Bovine Tuberculin Purified Protein Derivative in the Target Species.

Since 1986, use of a Bovine International Standard (BIS) for bovine tuberculin has been required to ensure national and international uniformity regarding the potency designation of bovine tuberculin Purified Protein Derivative (PPDb) preparations produced by multiple manufacturers. The BIS is the unique golden standard in the guinea pig potency assay, representing 100% potency, where potencies of production batches are calculated as relative potencies in comparison with the potency of the BIS which was set at 32,500 international Unit (IU) per mg. The stock supply and lifetime of the BIS is limited.The aim of this study was to develop a model to determine the potency of a newly produced in-house Reference Standard (RS) for PPDb with great accuracy in the target species (cattle) and to prove its precision and accuracy in the guinea pig potency test. First simulations were done to estimate the required number of cattle needed. Then, 30 naturally bTB infected cattle were subjected to a tuberculin skin test using multiple injections of both the RS and the BIS. Both were applied randomly in the same volume and concentration (1 dose). The potency of the RS against the BIS was directly derived from the least square means (LSMEANS) and was estimated as 1.067 (95% CI: 1.025–1.109), equal to a potency of 34,700 ± 1,400 IU/mg. In six guinea pig potency assays the RS was used to assign potencies to production batches of PPDb. Here, precision and accuracy of the RS was determined according to the parallel-line assay. Relative potencies were estimated by exponentiation of the common slope. The corresponding 95% confidence intervals were obtained according to Fieller's theorem. In sensitized guinea pigs, the relative potency of the RS against the BIS was 1.115 (95% CI: 0.871–1.432), corresponding to an absolute potency of 36,238 IU/mg (95% CI: 28,308–46,540).In conclusion: the method used to determine the potency of the RS against the BIS in naturally bTB infected cattle, resulted in a highly accurate potency estimate of the RS. The RS can be used in the guinea pig test to assign potencies to PPDb production batches with high precision and accuracy.

Prevalence of Bovine Tuberculosis among Buffaloes Innorth Karnataka

The present study was undertaken to assess the prevalence of bovine tuberculosis among buffaloes in Belgaum, Dharwad and Bagalkote districts of North Karnataka, for a period of eight years (2002 to 2009). A total of 2184 buffaloes belonging to 30 organized farms were screened by single intradermal tuberculin test using bovine tuberculin Purified protein derivative. Overall prevalence of tuberculosis among buffaloes was found to be 0.96 per cent. Prevalence was higher in females (0.97%) than males (0.84%) and in Murrah (1.02 %) than Surthi (0.85 %). Analysis of the temporal pattern revealed a gradual declining trend over a period of eight years.

Short communication: Proteomic characterization of tuberculin purified protein derivative from Mycobacterium bovis

Bovine tuberculin purified protein derivative (bPPD) is used as an intradermal test (IT) reagent to detect bovine tuberculosis (bTB) in most countries. Identification of bPPD proteins is critical to understanding the immunological reaction of IT at the molecular level. While bPPD from the United Kingdom (UK) and Brazil (BR) have been recently defined at the proteomic level, bPPD from the Republic of Korea (KR) has not yet been analyzed. Here, bPPD KR proteome was examined for the first time. In total, 271 proteins were identified, including Mycobacterium bovis-specific proteins Mb0854c and Mb2898, and 42 known T cell antigens. On comparing with proteomes of bPPD UK and BR, 33 proteins were found to be common among all three bPPDs, of which 15 proteins were T cell antigens. M. bovis-specific antigens with T cell activity in bPPD may be novel candidates for use as alternatives to currently available bPPD in diagnostics.

Effect of an inactivated paratuberculosis vaccine on the intradermal testing of goats for tuberculosis

The effect of an inactivated paratuberculosis vaccine on the diagnosis of tuberculosis (TB) in goats was investigated in a herd with a history of clinical paratuberculosis but which was free of TB. Cohorts of animals in 2006, 2008 and 2009, were vaccinated once at 1 month of age, and 50% of the 2006 cohort served as unvaccinated controls. The goats were aged 8 months, 20 months and 3.5 years old at the time of the survey. All animals were assessed using a single intradermal injection of bovine tuberculin purified protein derivative (PPD) (SID test), or using both bovine and avian PPD (CID test). An interferon (IFN)-γ assay using both bovine and avian PPD was carried out on the 2006 cohort and was interpreted according to three different 'cut-off' points. No unvaccinated (control) animals tested positive to any of the assays, confirming that the herd was TB-free. The SID test had a low specificity in vaccinated animals at 8 and 20 months of age, whereas the CID test demonstrated 100% specificity in animals ≥20 months-old. The specificity of IFN-γ assay was less than maximal for vaccinated animals 3.5 years old as small numbers of false positives were detected, although this depended on the chosen cut-off point. The study findings demonstrate that the use of an inactivated paratuberculosis vaccine in goats <1 month-old in a TB-free herd does not result in false positives to a CID test for TB when performed in animals ≥20 months-old.

Intradermal tuberculin testing of wild African lions ( Panthera leo) naturally exposed to infection with Mycobacterium bovis

African lions in the southern half of Kruger National Park (KNP) are infected with Mycobacterium bovis. Historically, reliable detection of mycobacteriosis in lions was limited to necropsy and microbiological analysis of lesion material collected from emaciated and ailing or repeat-offender lions. We report on a method of cervical intradermal tuberculin testing of lions and its interpretation capable of identifying natural exposure to M. bovis. Infected lions ( n = 52/95) were identified by detailed necropsy and mycobacterial culture. A large proportion of these confirmed infected lions (45/52) showed distinct responses to bovine tuberculin purified protein derivative (PPD) while responses to avian tuberculin PPD were variable and smaller. Confirmed uninfected lions from non-infected areas ( n = 11) responded variably to avian tuberculin PPD only. Various non-tuberculous mycobacteria (NTM) were cultured from 45/95 lions examined, of which 21/45 were co-infected with M. bovis. Co-infection with M. bovis and NTM did not influence skin reactions to bovine tuberculin PPD. Avian tuberculin PPD skin reactions were larger in M. bovis-infected lions compared to uninfected ones. Since NTM co-infections are likely to influence the outcome of skin testing, stricter test interpretation criteria were applied. When test data of bovine tuberculin PPD tests were considered on their own, as for a single skin test, sensitivity increased (80.8–86.5%) but false positive rate for true negatives (18.75%) remained unchanged. Finally, the adapted skin test procedure was shown not to be impeded by persistent Feline Immunodeficiency Virus Ple co-infection.

Prevalencia comparativa de tuberculosis en dos rebaños lecheros de la India

Holstein Friesian cows and their crossbred progeny on a farm in northern India were tested for tuberculosis (TB) infection using a single intradermal tuberculin test. The results showed that the animals persistently harboured TB infection for periods of two to four years. The recent comparative intradermal tuberculin test revealed that at least five out of nine of these cattle reacted positively to bovine tuberculin purified protein derivative. A high (15.76%) prevalence rate resulted because none of the infected animals had been segregated or culled from the herd since the first incidence was detected in 1992. In contrast, another farm in western India that practiced segregation and culling was able to contain the level of prevalence of TB between 0.65% and 1.85%. These findings call for stricter regulations on the management of TB at farm, state and country level and a revision in the mode of breeding programmes adopted by farms.

Protein G-based enzyme-linked immunosorbent assay for anti-MPB70 antibodies in bovine tuberculosis

MPB70 is a highly species specific protein which is secreted from Mycobacterium bovis during culture. To investigate whether antibodies against MPB70 can be used as an indicator of infection with M. bovis, an enzyme-linked immunosorbent assay was developed, based on the use of biotinylated protein G, to provide a common indicator for antibody formation in different species. During experimental infection with M. bovis in cattle, a characteristic pattern of anti-MPB70 antibody production was observed with an initial flat plateau followed by a marked rise 18 to 20 weeks after infection. Skin testing with bovine tuberculin purified protein derivative (PPD), which was shown to contain antibody-reactive MPB70, was a potent stimulator of antibody production in infected animals. In experimentally infected cattle, we observed an inverse relationship between antibody activity and delayed-type hypersensitivity skin test reactions. In natural M. bovis infections, skin testing with PPD was also a potent stimulator of anti-MPB70 formation. Comparison between the enzyme-linked immunosorbent assay for antibodies to MPB70 and that for antibodies to the widely cross-reacting M. bovis BCG antigen 85B in animals with M. bovis, Mycobacterium avium, Mycobacterium paratuberculosis, and Corynebacterium pseudotuberculosis infections showed that formation of antibody to MPB70 was highly specific for infection with M. bovis. The use of an MPB70-containing PPD preparation for skin testing followed by this anti-MPB70 assay is a highly specific indicator of M. bovis infection. Adjustment of the test conditions is expected to provide an increased sensitivity of the procedure for the diagnosis of natural M. bovis infections.

Comparison of the specificty of human and bovine tuberculin PPD for testing cattle. 1--Republic of Ireland

A tuberculin testing trial in cattle was carried out in the Republic of Ireland to compare the specificity for bovine tuberculosis of a human purified protein derivative (PPD) tuberculin (Weybridge) with that of a bovine PPD (Rotterdam), and to determine whether discrimination between specific and non-specific reactions to mammalian tuberculin is better with doses of tuberculins smaller than those traditonally used for testing cattle. Tests were carried out in 510 cattle, 395 of which were shown by post mortem examination to be tuberculous and 115 non-tuberculous. Three dilutions at five-fold intervals of both mammalian tuberculins were used together with two dose levels of avian tuberculin PPD (Weybridge), and all reactions were measured both by increase in skin fold thickness and by diameter of induration. In the environment of this trial, the bovine PPD was shown to be more specific for bovine tuberculosis than the human PPD, and particularly in differentiating from "skin tuberculosis". There was no indication of greater specificity at lower doses of tuberculin. Measurement of induration diameter proved a satisfactory alternative method of reading tuberculin reactions in cattle under field conditions.

Starch-agar-gel electrophoresis of tuberculoproteins from heated culture filtrates.

IN order to improve the specificity of a bovine tuberculin purified protein derivative, precipitated with trichloracetic acid from heated culture filtrates1, we decided to investigate its protein composition2, and in this connexion we experimented with zone electrophoresis on paper-strips. Now this procedure has hitherto not been very successful3–5, and in spite of our own numerous experiments with various procedures and methods we did not obtain anything other than unusable pictures of ‘comets’ or streaks. (This is in contrast with the more satisfying results obtained by others with non-heated tuberculins4,5.) Smithies introduced starch gel electrophoresis which seems to be of great value in determining the ultrastructure of serum-protein patterns6,7, the composition of toxins8 and of cerebrospinal fluid9. Sorkin et al. 10 made preparative separations of some tuberculoprotein preparations from unheated culture filtrates by electrophoresis in starch gels, followed by transfer into glass. Our own investigations on this starch-gel electrophoresis led to the following method.