Antibodies, developing in animal and human organisms against antigens of external and internal origin are not limited with opsonization functions, lying on the base of formation of humoral immunity. Being the product of somatic mutations of plasmatic cells, according to clonal selection theory of immunity, they themselves are also alien proteins for organisms. Thus, they themselves also begin to display antigen pressure on the immune competent system. So, they will start themselves the elaboration of antibodies against them, which are called anti–idiotypic ones. Anti–idiotypic antibodies, imitating the corresponding bacterial and virus antigens are able to initiate the immune response of animal organism against them, which play great immune modulating role.
The immunological structure of populations of Karakul sheep lambs vaccinated against E. coli bacteria, salmonellosis and anthrax antigen from the age of 2–3 days till 2–3 weeks was studied. Experiments were carried out in the 1–2, 3–4, 5–6, 7–8, 9–10 and 11–12 weeks old Karakul lambs. Experimental lambs during appraisal were vaccinated once by associated hydroxide aluminum form vaccine against paratyphoid and coli bacteriosis of calves, pigs and lambs. In another experiment, the lambs were immunized by rare naturally occurring bacterial antigen. As such an immunogenic was selected sterile soluble anthrax antigen. Developed and tested in the application of Ascoli reaction the role of anti–idiotype antibodies in the formation of natural immunity against opportunistic pathogens identified the nature of normal antibodies was studied. The nature of wavelike character of the immune reaction of an organism of newborn animals of vaccination was revealed. Also the immunomodulation role of anti–idiotypic antibodies was determined.