Anthrax Vaccine Immunity
Investigation of Cellular and Human Immunities Induced by Chemical and Live Anthrax Vaccines
Tech Area / Field
3 Approved without Funding
State Research Center for Applied Microbiology, Russia, Moscow reg., Obolensk
Project summarySince anthrax exotoxin is the molecular entity responsible for the whole anthrax syndrome, vaccine-induced effective immunity should be primarily antitoxic. Therefore, all standard vaccines induce the formation of antibodies against exotoxin components, however not all of these antibodies effectively neutralize the action of exotoxin. Antibodies against two epitopes of protective antigen and lethal factor were found to be most effective. Until now, no systemic studies have been conducted to estimate the proportion of these very antibodies in the whole pool of antibodies induced by various vaccines. The contribution of cellular immune response to the efficacy and reactogenicity of anthrax vaccines has not been studied so far. Reorganization of the cellular immune response induced by anthrax vaccines is evidenced by numerous results of skin tests, as well as by the data on the cytokine stimulation resulting from exotoxin action on macrophages.
Therefore developed Anthrax vaccines contain in the structure these antigens. However antibodies are quickly removed from immunized organism after fifth - sixth month enough. There is a necessity of repeated vaccine application (buster). From vaccinated organism after the second - third vaccine application there are reactions, which are possible to characterized, as allergy and immunological tolerance. Т-lymphocytes response for these reactions in organism. In this connection we offer to investigate reorganization of cellular immunity induced by various preparations, including recombinant which will consist of various PA/LF fragments. The various Т-lymphocytes (CD4, CD8 and other) from animal vaccinated by various preparations will be investigated for this purpose. Besides we are represented urgent to evaluate synthesis some cytokines at repeatedly immunized animals (IL-2, IL-8, IL-6, IL-4, ?INF). It would allow to reveal what fragments or whole molecules introduce the main in reactogenity of vaccines and to develop preparations, in which these parts of molecules will be absent.
The main goal of the project is to elucidate the molecular and cellular mechanisms of immunogenesis induced by standard anthrax vaccines to provide the basis for the construction of molecular vaccines.
The tasks of project are next:
1. Development of the cell model for the determination of spore germination (J774A.1/RAW264/? will be used as target-cells).
2. Determination of efficiency of the antibody induction after vaccination of effective dozes (STI-1, RUS/USA/UK vaccines) in various laboratory animals (mouse, golden hamsters, guinea pigs, rabbits) by means cell model.
3. Eliciting of functioning active toxin epitopes on cell model. The various fragments of toxin components will be used as analogues of functional-active epitopes for neutralization of antibodies in these investigations. Monoclonal antibodies against functioning active epitopes will be used also if USA investigators (USAMRIID) will transmit them to us.
4. The characteristic of reorganization cell immunity after immunization by various vaccines (STI-1, RUS/USA/UK chemical vaccines). These changes will be determined in quantity of receptor on various immune cells (CD4, CD8, CD44, CD45 and others) by means flowing cytofluorimeter.
5. Determination of a role of anthrax toxin components (including them epitopes) in reorganization of cell immunity. This approach will elicit the contribution of various components in vaccine reactogenity. In this stage of investigations we will use methods of protein engineering. Various fragments and them combinations (fused) will be constructed (PA17, PA20, PA37, PA47, PA63, LFn, LF55, PA?-LF?) for this goal.
6. The molecular-cell model of anthrax infection will be constructed as result of these investigations.