Effect of immunization of lambaris (Astyanax altiparanae) with the immobilization antigen IAG52A from Ichthyophthirius multifiliis associated with the cytokine IL-8 from A. altiparanae as a molecular adjuvant

• Grant number: 20/06371-4
• Support type: Scholarships in Brazil - Master
• Effective date (Start): September 01, 2020
• Effective date (End): May 31, 2022
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal researcher: Antonio Augusto Mendes Maia
• Grantee: Caroline Munhoz Meira
• Home Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil

Abstract

Lambari (Astyanax altiparanae) is a small characiform fish found in rivers in the South American neotropical region that has been gaining prominence in national aquaculture mainly for its potential use as a snack, canned food and fishing bait. In addition, lambari is also widely used as model in research, since it has high growth rates, easy reproduction and rapid sexual maturation. The growing importance of this fish stresses the necessity to develop alternatives for the control of diseases that affect it, like ichthyophthiriasis. This disease, also known as "white spot disease", is caused by the ciliated protozoan Ichthyophthirius multifiliis, an obligate parasite that affects many species of freshwater fish. Currently, ichthyophthiriasis is responsible for major losses in Brazilian and worldwide fish industry. However, there are no efficient treatments for the control of this pathogenesis in large scale productions, which makes the adoption of preventive strategies essential. Therefore, the objective of the present project is to recombinantly produce the immobilization antigen IAG52A of I. multifiliis and to evaluate its efficiency in the immunization of A. altiparanae, together with the cytokine IL-8 obtained from lambaris as molecular adjuvant. In the first stage of this project, the expression and purification of recombinant proteins in Pichia pastoris yeasts will be carried out. The proteins will be administered to the fish and, to check the immunogenic effect, the expression analysis of inflammatory cytokines, IL-1², IL-8, TNF± and IFN³ and of the gene that expresses the IgM antibody will be performed by real-time PCR (qPCR) in the spleen and anterior kidney of the animals. Finally, immunized fish will be challenged with a lethal dose of I. multifiliis terontes in order to evaluate the effects of immunization through the mortality and morbidity rates of the animals. (AU)