Generation of microalga Chlamydomonas reinhardtii expressing protein as oral vaccine candidate for shrimps against White Spot Syndrome Virus (WSSV) infection

Abstract White Spot Syndrome Virus (WSSV) is a major cause of mortality in shrimp cultivation on farms all around the world. The serious monetary losses related with its occurrence in susceptible shrimps and the limitations of current methods used to treat WSSV disease in Vietnam, highlight the need for new methods to prevent and to manage the disease. The current study investigates the possibility of expressing the VP28 protein of WSSV from the nucleus of Chlamydomonas reinhardtii for WSSV control. The VP28 protein of WSSV was successfully expressed in C. reinhardtii as confirmed by Western blot analysis and RT-PCR. The immunological parameters analyzed in shrimp administered with 4 mg of dried algae (~ 6 × 107 cells)/1 g shrimp showed a high-level expression of lysosome (LSZ), anti-lipopolysaccharide factor (ALF), superoxide dismutase (SOD) and prophenoloxidase (proPO) compared to the control group. The result of oral administration experiments indicated that vaccinated shrimp survived up to 70% of the time as opposed to control group with 100% mortality. Taken together, the result indicated that recombinant C. reinhardtii expressing VP28 has a potential utility as an oral vaccine candidate against WSSV.