Flounder Infected With Lcdv Target Organ Positioning And The Detection Of Antibody Levels

Lymphocystis disease (LCD), an important fish disease, is a chronic disease characterized by papilloma-like lesions typically on the skin, fins and tail. These lesions usually regress spontaneously and fish may recover. In this study, the LCDV was purified from the diseased flounder Paralichthys olivaceus with typical lymphocystis symptom. Then healthy flounders (Paralichthys olivaceus) were infected with Lymphocystis disease virus (LCDV). LCDV positive signs were detected in tissues by immunofluorescence antibody technique (IFAT). The total and specific serum antibody levels of infected Japanese flounder were detected by an enzyme linked immunosorbent assay (ELISA) using the monoclonal antibodies (Mabs) against the Ig of Japanese flounder (P. olivaceus). And the specific serum antibody levels of immunised flounder with LCDV inactivated vaccine were detected. The followings are the details.The monoclonal antibodies (Mabs) against the LCDV and the monoclonal antibodies (Mabs) against the Ig of Japanese flounder (P.olivaceus) were produced largely by preparation of the ascites. 4 Mabs against the LCDV (2A9,1A8,1B2 and 3G3) and 10 Mabs against the Ig of Japanese flounder (2D8,2H1,1E1,1C12,2E6,1E7,1B11,4D1,2A7 and 2E8) were produced and purified.The virus is separated from lymphocystis nodules of flounder (Paralichthys olivaceus) surface and purified by discontinuous density gradient centrifugation method. Healthy flounders (Paralichthys olivaceus) were infected with Lymphocystis disease virus (LCDV), sera and tissues were collected every 7 days. Gills, kidneys, spleens, livers, intestines, coelom velums and epidermis were embed by OCT. The tissues were sliced up by Leica CM1900 freezing microtome. LCDV positive signs were detected in the intestine and stomach after two weeks by immunofluorescence antibody technique (IFAT).The total and specific serum antibody levels of infected Japanese flounder were detected by an enzyme linked immunosorbent assay (ELISA) using the monoclonal antibodies (Mabs) against the Ig of Japanese flounder (P. olivaceus).The results revealed that the total and specific serum antibody levels of Japanese flounder increased evidently after one week. The specific antibody level of ELISA absorbance increased from 0.129 for control group to 0.238, then it went on rising on the 2nd week (0.247) and 3rd week (0.410), and reached the peak of 0.436 on the 4th week, afterwards it decreased slowly (0.385 for the 5th week, 0.357 for the 14th week); The total antibody level of ELISA absorbance increased from 0.135 for control group to 0.250; which was 0.266 on the 2nd week and 0.561on the 3rd week ,and peaked on the fourth week at 0.613, then decreased slowly (the fifth week 0.480, the fourteenth week 0.475).