Antigen carrier

Proposed Ph.D topic on Evaluation of micro and nano particle based protein/antigen carriers in fish :

Proposed Ph.D topic on Evaluation of micro and nano particle based protein/antigen carriers in fish Presented by Truptimayee Behera Research Associate Supervisor Dr P. Swain, M.V.Sc., Ph. D Senior Scientist Fish Health Management Division Central Institute of Freshwater Aquaculture Kausalyaganga, Bhubaneswar-751 002 (Orissa)

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Antigen : Those substances that can induce a specific immune response and bind specifically to antibodies produced against it. Antigenicity: the ability to interact with an antibody Immunogenicity: the ability to induce an immune response Hapten: an low molecular weight antigen that is not immunogenic

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Properties of antigen: Antigens are mainly proteins, carbohydrates, lipids and protein complexes Foreignness Molecular weight Chemical complexity, Physical nature, size

Vaccines:

Vaccines A vaccine is a biological preparation that improves immunity against a particular pathogen. A vaccine has two parts( immunogenic and antigenic). Types of vaccines Killed whole cell Live-attenuated Recombinant DNA-based Recombinant protein-based Peptide vaccine Genetically modified live vaccine DNA vaccines

Inefficiency of currently used vaccines:

Inefficiency of currently used vaccines New generation vaccine mainly contain purified proteins, peptides, recombinant proteins and are weakly immunogenic lack of appropriate adjutants Appropriate dose and rout of administration So for this antigen, harmless effective adjuvants or carriers are urgently needed in modern vaccine therapy

Adjuvants:

Adjuvants Adjutants are certain substances which can non-specifically enhance the Immune response or change the type of Immune response when it is injected before or together with the antigens. In briefly adjutants are components that are added to vaccine antigen to make them more them immunogenic.

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Drawbacks of several adjuvants: Aluminium adjuvants has inability to elicit cell mediated immune responses such as cytotoxic T cell responses Granuloma formations and local inflammations in oil adjuvants Freund’s complete adjuvant contain Mycobacterium : too harmful to be used as an adjuvant for human vaccines and restricted in certain countries. To avoid this, different polymeric as well as monomeric micro and nanoparticle based adjutants or carriers are better alternatives.

Vaccine/antigen carriers:

Vaccine/antigen carriers Vaccine or antigen or protein carriers are vehicles or transporters for a vaccine or An immunogenic molecule to which a hapten is bound

Why vaccine/antigen carriers are used ?:

Why vaccine/antigen carriers are used ? Maximum protection with less number of administration. To enhance the immune response weak antigens. Protect from acidic degradation in the peritonium in oral delivery. Induction of more prolonged immune responses with c ontrolled release of antigen

Types of antigen/vaccine carriers used in medical and veterinary vaccines:

Types of antigen/vaccine carriers used in medical and veterinary vaccines Natural Protein : gelatin, albumin, Collagen, Polysaccharides : alginate, dextran, Chitin, chitosan. Lipids: Lecithin, liposomes Disadvantages Poor batch-to-batch reproducibility Specific condition for the degradation Potential antigenicity Synthetic Polyesters : poly( ε -caprolactone) (PECL), PLA, PLGA Poly(alkylcyanoacrylate) (PACA) Poly D, L-lactic-Co-glycolic acid(PLGA), Polylactide(PLA), Polytetraflourothylene(PTFE),

Biodegradable carriers:

Biodegradable carriers Alginate, chitosan, dextran, gelatin . PLGA, PLA, poly(acrylcyanoacrylate), PECL(Poly( έ-caprolactone)

Micro particulate adjuvants or carriers:

Micro particulate adjuvants or carriers Microparticles from natural or synthetic compound mostly microsphere and microcapsules Antigens coated with microparticles by covalent or non-covalent linkage and by physical entrapments. Advantage: fewer antigen is required more efficiently presented to antigen presenting cells less number of dose is required.

Nano particulate adjuvants or carriers:

Nano particulate adjuvants or carriers The structure and properties of microparticles can be changed markedly with slight alternations in production conditions, to elicit significant change in immune responses. To avoid this sub micron particles, also called as nanoparticles can be used. It can reach the target organ more efficiently than the microparticles. By this we can change the surface charge and polarity

Vaccines available for fish:

Vaccines available for fish Fish vaccinology also faces similar problems for vaccine designing like that of animal or human vaccine. Main diseases controlled through vaccination Vibriosis caused by Vibrio anguillarum serotypes 01 and 02 Furunculosis associated with Aeromonas salmonicida Enteric redmouth (ERM) – Yersinia ruckeri Infectious pancreatic necrosis caused by IPN virus. Salmon pancreas disease caused by SPD virus. Although these vaccines are available these are not commercialized till date. Recently only two live attenuated vaccines are commercially available in U.S. for septicemia of catfish(by Edwardsiella ictaluri) and columnaris disease ( by Flavobacterium columnare).

Objectives :

Objectives To screen the efficacy of different protein/antigen carriers in fish. To evaluate the form (micro/nano) of different carriers in enhancing the immunity and persistence of desired antigen. To find out effective route and proper dose of the carrier conjugated antigen/protein. To find out desire release profiles or the stability of protein and antigen absorbed on the surface of different carrier molecules.

Technical programme:

Technical programme First year Procurement of natural and synthetic materials for use as vaccine carriers Conjugation of a suitable protein antigen with different carriers. Evaluation of different dose and size of the carrier particle and their route of the administration. Assessment of antibody response.

Technical programme:

Technical programme Second year Conjugation with specific proteins and microbial antigens. Evaluation of different dose and size of the carrier particle and their route of the administration will continue. Assessment of specific and non-specific immune parameters in immunized fishes using suitable techniques.

Technical programme:

Technical programme Third year Analysis and interpretation of data Thesis writing

Expected outcome:

Expected outcome A suitable protein/vaccine carrier will be known for future use in aquaculture. Further, the knowledge gained from this study will be used by the researchers for designing a suitable vaccine

Practical and scientific utility:

Practical and scientific utility Suitable carrier will be known which can further be used in administration of vaccines and protein delivery to target areas. Fish can be used as an experimental animal model for the evaluation of protein and antigen carrier in higher vertebrates . A suitable carrier, its form and rout of administration will be evolved so it can be used in other higher vertebrates including human. The knowledge/publications will help other researchers in the field of vaccination and protein delivery.

Selected references:

Selected references 1.Sourabhan S, Kaladhar K, Sharma CP. Method to enhance the encapsulation of biologically active molecules in PLGA nanoparticles. Trends in Biomaterials and Artificial Organs 2009;22:207-11. 2.Gupta RK, Siber GR. Adjuvants for human vaccines-current status, problems and future prospects. Vaccine 1995;13:1263-76. 3. Men Y, Thomasin C, Merkle HP, Gander B, Corradin G. A single administration of tetanus toxoid in biodegradable microspheres elicits T cell and antibody response similar or superior to those obtained with aluminum hydroxide.Vaccine 1995;7:683-9. 4. Brian R. Sloata, Michael A. Sandoval , Andrew M. Hau , Yongqun He , Zhengrong Cui. Strong antibody responses induced by protein antigens conjugated onto the surface of lecithin-based nanoparticles. Journal of Controlled Release 2010; 141 93 – 100.

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