EN
Efforts at devising new vaccinations against fish disease involve using antigens which are comprised of compounds contained in the cell membrane of bacteria or extracellular compounds excreted by them. The compounds which are the subject of this type of research are lipopolisaccharides (LPS), polysaccharides (EPS), protein layer A (А-layer), protein regulating the collection of iron substances from the medium, as well as protein ECP extra-cellularly excreted by bacteria. Research is also being conducted into finding an immunogenic compound through using biotechnological methods. One example is obtaining an immunogenic gluco- protein typical for virus 1HN in insect cells, into which the IHNV gene which codes this protein has been previously introduced by use of a vector. As a result of the fact that the most immunologically active atnino- -acid sequence in the IHN glucoprotein virus is 336-444, an attempt has been made to create a vaccination which would contain this sequence. The latter has been synthesised in Escherichia coli plasmodia into which the appropriate gene of the IHN virus has been introduced. Attempts have also been made to inoculate fish with IHN glucoprotein synthesised in-vitro. The article also presents new methods of attenuating bacteria and virus antigens. Attenuation of Aeromonas salmonicida has been achieved through depriving it of protein A and of antigen О in LPS or through removing gene AroA from its genome. Further examples of new methods of attenuation have concerned Renibacterium salmoninarium. Protein p57 has been degraded in the cellular membrane of this bacteria. Attenuation of IHN virus has been achieved by its mutation caused by cultivating it in the presence of neutralising antibodies. The attenuation of herpes virus CCV has also been achieved by depriving it of the tymidine kinase gene. The paper additionally reviews the first research into creating a genetic vaccination for fish.