[The new generations of vaccines against parasites].
The protection of humans and domestic animals against parasitic infections remains a major goal, especially in light of developing of drug resistant strains in many parasite species. "Classic" vaccines are based on attenuated infective stages of protozoan and helminth parasites. Although such vaccines are effective in confering host immunity against several protozoan (coccidiosis, giardiosis, toxoplasmosis) diseases and one helminth (dictyocaulosis) they are very unstable and expensive. Recombinant techniques enable to obtain protective antigens quickly and in considerable quantities, cultivating of the bacteria and purification of the recombinant protein is less expensive than the maintenance of host animals and isolation of the protective antigens from harvested parasites. Moreover, the cloned protective antigens may be deprived of epitopes responsible for immunopathology. However, at present only one anti-parasite recombinant protein vaccine is commercially available (TickGARD). Such a situation may result from that many protective parasitic antigens cannot be expressed in bacteria or yeast in anative from. DNA vaccines present many advantages over protein ones. Firstly, the antigenic proteins synthesised within the host cell possess an appropriate molecular structure and undergo a post-translational modifications specific for a native protein. The next advantage of DNA vaccines is that DNA is easier to handle and more resistant than proteins to temperature changes. DNA vaccines are likely to induce novel mechanisms of immune response, which may be beneficial in case of parasitic invasions. Costs of DNA vaccines are comparable, and may be even lower, in comparison to recombinant protein vaccines. The main obstacle preventing the use of DNA vaccines is still lack of the complete knowledge concerning mechanisms of their action. Vaccines based on transgenic plants (=edible vaccines), expressing the protective parasitic antigens, present another promising approach in research on anti-parasitic vaccines. Such vaccines may be of special importance in prevention of infections with gastrointestinal parasites.
Wedrychowicz
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Katedra Parazytologii i Chorób Inwazyjnych, Wydział Weterynaryjny SGGW, Warszawa.
D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology; D000953:Antigens, Protozoan / Q000276:immunology; D006801:Humans; D010271:Parasites / Q000235:genetics / Q000502:physiology; D010272:Parasitic Diseases / Q000276:immunology / Q000517:prevention & control*; D016052:Protozoan Vaccines / Q000276:immunology / Q000627:therapeutic use*; D019444:Vaccines, DNA / Q000276:immunology / Q000627:therapeutic use*; D022462:Vaccines, Edible / Q000276:immunology / Q000627:therapeutic use*; D022223:Vaccines, Subunit / Q000276:immunology / Q000627:therapeutic use*
D000947:Antigens, Helminth; D000953:Antigens, Protozoan; D016052:Protozoan Vaccines; D019444:Vaccines, DNA; D022462:Vaccines, Edible; D022223:Vaccines, Subunit