MA, T.H.T.*; CHAN, S.-M.; The University of Hong Kong: Characterization of the C-type lectin cDNA from the shrimps Penaeus monodon and Litopenaeus vannamei

White Spot Syndrome (WSS) is one of the most reported viral diseases in shrimp. It is caused by the infection of the wide host-ranged White Spot Syndrome Virus. Because of the high mortality rate occurred in shrimp infected by WSSV, huge economic loss has resulted during the outbreak of WSS. Since the shrimps do not possess immunoglobulins and a specific immune system, they rely mainly on innate immunity to defend foreign invasions. Recently, an antiviral gene encoded for a protein that contains a C-type lectin like domain (CTLD) was reported in the shrimp Penaeus monodon. In order to study the role of lectin as non-self recognition molecules, the genes encoded for the lectins of Penaeus monodon and Litopenaeus vannamei were characterized by PCR cloning approach. The cDNA of the shrimp has been cloned. The longest open reading frame (ORF) of the lectin genes for P. monodon and L. vannamei were 999 nt and 1018 nt respectively. Despite of the low overall amino acid sequence identities between the lectins of the two species, RNA transcripts for the lectins can be detected only in the hepatopancreas of the shrimps. When the juvenile P. monodon was challenged with shrimp extract containing White Spot Syndrome Virus (WSSV), the expression pattern of lectin was changed. The result suggested that these lectins may be involved in the control of disease through the regulation of lectin expression. Supported by the RGC (HKU7322/03M) of the Hong Kong SAR government