Adjuvants are substances distinct from antigens that enhance T and B cell activation mainly by promoting the accumulation and activation of antigen presenting cells (APCs) at the site of antigen exposure. Adjuvants (Latin: “adjuvare,” meaning “to help”) are designed to improve poorly immunogenic vaccines. Adjuvants were originally described by Ramon as ‘substances used in combination with a specific antigen that produced a more robust immune response than the antigen alone,’ thus encompassing a wide range of materials. One of the most important strategies for the development of effective new vaccines is the selection and usage of a suitable adjuvant. Immunologic adjuvants play a very important role in enhancing vaccine potency by improving the humoral and cell-mediated immune responses to vaccine antigens. In this review, we summarize the recent advances that are taking place in the development of potent adjuvants in human and veterinary vaccines.
BACKGROUND:Bovine tuberculosis (bTB) is a chronic disease that results from infection with any member of the Mycobacterium tuberculosis complex. Infected animals are typically diagnosed with tuberculin-based intradermal skin tests according to World Organization of Animal Health which are presently in use. However, tuberculin is not suitable for use in BCG-vaccinated animals due to a high rate of false-positive reactions. Peptide-based defined skin test (DST) antigens have been identified using antigens (ESAT-6, CFP-10 and Rv3615c) which are absent from BCG, but their performance in buffaloes remains unknown. To assess the comparative performance of DST with the tuberculin-based single intradermal test (SIT) and the single intradermal comparative cervical test (SICCT), we screened 543 female buffaloes from 49 organized dairy farms in two districts of Haryana state in India. RESULTS:We found that 37 (7%), 4 (1%) and 18 (3%) buffaloes were reactors with the SIT, SICCT and DST tests, respectively. Of the 37 SIT reactors, four were positive with SICCT and 12 were positive with the DST. The results show that none of the animals tested positive with all three tests, and 6 DST positive animals were SIT negative. Together, a total of 43 animals were reactors with SIT, DST, or both, and the two assays showed moderate agreement (Cohen's Kappa 0.41; 95% Confidence Interval (CI): 0.23, 0.59). In contrast, only slight agreement (Cohen's Kappa 0.18; 95% CI: 0.02, 0.34) was observed between SIT and SICCT. Using a Bayesian latent class model, we estimated test specificities of 96.5% (95% CI, 92-99%), 99.7% (95% CI: 98-100%) and 99.0% (95% CI: 97-100%) for SIT, SICCT and DST, respectively, but considerably lower sensitivities of 58% (95% CI: 35-87%), 9% (95% CI: 3-21%), and 34% (95% CI: 18-55%) albeit with broad and overlapping credible intervals. CONCLUSION:Taken together, our investigation suggests that DST has a test specificity comparable with SICCT, and sensitivity intermediate between SIT and SICCT for the identification of buffaloes suspected of tuberculosis. Our study highlights an urgent need for future well-powered trials with detailed necropsy, with immunological and microbiological profiling of reactor and non-reactor animals to better define the underlying factors for the large observed discrepancies in assay performance, particularly between SIT and SICCT.
AbstractBovine tropical theileriosis (BTT), a globally distributed disease, is caused by Theileria annulata and transmitted by Hyalomma species of ticks. While polymerase chain reaction (PCR)-based assays are sensitive and specific for detection of this disease, their practical application in the field is limited by the requirement for sophisticated instruments. The loop-mediated isothermal amplification (LAMP) assay emerges as a highly efficient, sensitive, and rapid nucleic acid amplification method that also requires minimal complex instrumentation for operation. Therefore, the present study aimed to develop a LAMP assay targeting a partial, cytochrome b gene of T. annulata, facilitating the visualization of LAMP products with the naked eye using pH-sensitive dye (phenol red). Positive LAMP products were confirmed by a ladder-like pattern in agarose gel electrophoresis. No amplification was detected with the DNA of other haemoprotozoans. The results of the LAMP assay were compared with those of blood microscopy and PCR assays. Among the 200 samples tested, LAMP identified 23 cases of infection, while blood microscopy and PCR detected infections in 16 and 20 samples, respectively. The findings of this study suggest that the LAMP assay exhibited higher sensitivity and specificity compared to PCR and blood microscopy, which may enable field-level diagnosis of BTT.
AbstractA study was undertaken to develop a paper-based colorimetric loop-mediated isothermal amplification (LAMP) assay for the diagnosis of bovine tropical theileriosis. The hydroxy naphthol blue (HNB) wet LAMP assay was standardized for diagnosis of Theileria annulata in cattle. Further, the optimized wet LAMP assay was performed on a suitable paper substrate for the standardization of HNB paper LAMP with required modifications. The drying of colorimetric LAMP reagents on paper substrate allowed the transport of the ready-to-use LAMP kits to areas where the cold chain is not available and it can be employed for point-of-care diagnostics because of its single step operation.
Anaplasma genus has been classified under the family Anaplasmataceae of order Rickettsiales, which contains the spp. Anaplasma marginale, Anaplasma bovis, Anaplasma centrale, Anaplasma platys and Anaplasma phagocytophilum is accountable for a broad range of diseases in both man and animal medicine around the globe. A multiplex PCR procedure was designed to identify A. marginale, A. bovis, and A. platys simultaneously by employing species-specific primers targeting the msp4 (Anaplasma marginale), 16S rRNA (Anaplasma bovis), and groEL (Anaplasma platys) genes. The sensitivity of the assay was ascertained by tenfold dilutions of DNA obtained from cattle blood infected with A. marginale, A. bovis, and A. platys was used to evaluate the test sensitivity. A total of 31 Anaplasma genus positive samples were subjected to mPCR by using species specific primers for simultaneous detection of all the three species. All the 31 samples showed amplification of 753 bp fragment specific for A. marginale and 61.29
