Allergic activity and specificity of tuberculin preparations with 30-50% of weakly secreted mycobacterial antigens of tuberculosis

Abstract

Bovine tuberculosis remains a global problem. An intracutaneous test with tuberculin is the main method for determining the status of herds, which poses special requirements for the activity and specificity. The basis of cotemporal tuberculins are antigens of tuberculosis mycobacteria easily secreted to the liquid synthetic medium during growth, but a range of antigens with a low secretion index are in composition of tuberculins in small quantities. The purpose of the research is to obtain weakly secreted antigens from a production waste – autoclaved bacterial mass of production strain of tuberculosis mycobacteria (MTB) using ultrasound and nonionic detergent, to study the diagnostic properties of tuberculosis with 30-50% of such antigens. It has been determined that autoclaved bacterial mass of industrial MBT strain, which is a waste of tuberculin production, can be an additional source of tuberculoproteins, which are low-secreting (LS) MBT antigens, which in an equivalent dose are about 30% more active compared to standard tuberculin based on easily secreted antigens and is not inferior in terms of species specificity. Whereas, up to 50% of purified LS of tuberculoproteins from the bacterial mass can be included in tuberculin composition. The obtained preparation is not reactogenic, in an equivalent dose it does not differ in terms of activity from the international standard for PPD of tuberculin, but surpasses it in terms of species specificity. It has been shown that in herds with an undetermined tuberculosis status, 2.2 times more cows respond to tuberculins with 30-50% of purified LS tuberculoproteins compared to standard preparations based on easily secreted antigens of tuberculosis mycobacterium. Profound studies of reacting cows using methods for detecting the genome of tuberculosis mycobacterium and bacteriological markers of tuberculosis infection have confirmed the presence of latent tuberculosis infection in cow body. The inclusion of up to 50% of tuberculoproteins from the bacterial mass in tuberculin increases the diagnostic properties of the target product and significantly reduces its price cost.