A Kazal-type serine proteinase inhibitor SPIPm2 from the black tiger shrimp Penaeus monodon is involved in antiviral responses

A Kazal type serine proteinase SPIPm2 from the black tiger shrimp Penaeus monodon is capable of neutralization and protection of hemocytes from the white spot syndrome virus

“…It is expressed mainly in the shrimp hemocytes and may play important roles in the shrimp innate immunity [14,19,26]. We have also shown that the SPIPm2 is involved in antiviral defense against WSSV.…”

“…Recently, we have shown that injection of the rSPIPm2 prior to WSSV injection resulted in the inhibition of WSSV replication and prolonged the mortality rate of WSSV-infected shrimp [14]. It was, then, interesting to know how the rSPIPm2 performed its action against WSSV.…”

“…Previously, we showed that the SPIPm2 was expressed mainly in the hemocytes and secreted after WSSV infection [14]. To identify the hemocyte cell type that produced SPIPm2 and see how the WSSV infection affected the hemocytes, we used a confocal laser scanning microscope to visualize the hemocytes collected from normal, WSSV-infected shrimp at various time points and moribund shrimp.…”

“…It is a five-domain KPI with potent inhibitory activities against subtilisin and elastase [18] and possesses bacteriostatic activity against Bacillus subtilis [19]. The SPIPm2 is produced mainly by the hemocytes and secreted into the circulation [14]. In response to WSSV challenge, the SPIPm2 producing cells in the shrimp are reduced by more than half as they secrete the inhibitor into the circulation.…”

“…Injection of the recombinant SPIPm2 (rSPIPm2) into the shrimp before WSSV challenge attenuates the WSSV replication. Moreover, it helps prolong the lives of WSSV-infected shrimp [14].…”