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Made available in DSpace on 2018-11-26T16:01:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01. Added 1 bitstream(s) on 2021-07-15T14:31:33Z : No. of bitstreams: 1 S0102-09352018000100205.pdf: 1044733 bytes, checksum: 5d7b98ea3c5133227b108b64cb312c7c (MD5) This work aimed to evaluate the role of the spleen in storage and reactivation of the memory B cells, represented by IgM positive cells and the systemic production of sheep antibodies anti-red cell in Nile tilapia (Oreochromis niloticus). Two groups were established: the memory group, containing fish previously immunized with a 2,5% sheep anti-red cell, to generate the immune memory; and the naive group, containing fish that received a 0,65% saline solution. After 32 days, both groups were subjected to a new dose of the same antigen at the same concentration, volume, and inoculation via. The memory clones reactivation was correlated to the increase of the IgM positive cells in the spleen in the memory group at 0 day. The memory group showed an increase in the absolute number of lymphocytes at 21 days and an increase in the antibodies at 14 days after inoculation when compared to the naive group. The results suggest that the spleen may be a storage and reactivation place of memory B cells in Nile tilapia. Univ Estadual Paulista, Jaboticabal, SP, Brazil Univ Estadual Paulista, Araraquara, SP, Brazil Univ Estadual Norte Parana, Bandeirantes, PR, Brazil Univ Estadual Paulista, Jaboticabal, SP, Brazil Univ Estadual Paulista, Araraquara, SP, Brazil

Made available in DSpace on 2018-11-26T15:29:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-03-01. Added 1 bitstream(s) on 2021-07-15T14:31:15Z : No. of bitstreams: 1 S0102-09352016000200379.pdf: 249146 bytes, checksum: c2c71ff8c38c70a4fb7277067db15ad4 (MD5) The Streptococcus agalactiae bacteria is a potent agent which causes outbreaks of bacterial diseases in fish. The stress caused by management and poor environmental quality makes tilapia susceptible to infections, including by bacterium. The aim of this study was to evaluate the resistance of the Nile tilapia immunized with hyperimmune serum against S. agalactiae subsequently challenged with homologous strain of the same bacteria. After determining the DL 50 of S. agalactiae, 36 tilapias were distributed in 4 aquariums, 2 for the control group and 2 for the group via coelomic, inoculated with the DL 50 for anti-S. agalactiae antibodies production. On the 21st and 28th day blood was collected for the obtainment of hiperimmune serum used in passive transference. Then, 30 tilapias were distributed in 3 aquariums submitted to 3 treatments (GI: control; GII: immunized with inactivated-serum; GIII: immunized with non-inactivated serum). After 48 hours, 7, 14, 21, 28 and 35 days blood collections were done for anti-S. agalactiae antibodies titration using the direct agglutination test. For survival evaluation 30 tilapias were distributed in 3 aquariums and submitted to 3 treatments (GI: control; GII: immunized with inactivated-serum; GIII: immunized with non-inactivated serum). After 48 hours of inoculation tilapias were challenged with 100 mu L of S. agalactiae and monitored twice a day for 35 days. The results showed that titers of antibodies were detected by direct agglutination until the 21st day after passive transference and during the same period the protection between the groups immunized with inactivated serum and non-inactivated serum contending anti-S. agalactiae antibodies was of 80% after challenge with S. agalactiae. In the end, the serum-inactivated serum and active groups had 60 and 80% protection, respectively, while 100% of the fish in the control group developed severe signs of infection and were euthanized. There was no statistical difference in the survival rate between the immunized groups. Univ Estadual Londrina, Londrina, PR, Brazil Univ Estadual Paulista, Campus Jaboticabal, Jaboticabal, SP, Brazil Univ Estadual Norte Parana, Campus Luiz Meneghel, Bandeirantes, PR, Brazil Univ Estadual Paulista, Campus Jaboticabal, Jaboticabal, SP, Brazil

Made available in DSpace on 2022-04-28T19:53:57Z (GMT). No. of bitstreams: 0 Previous issue date: 1993-01-01 Depto. de Patologia Veterinaria Faculdade de Cienc. Agrarias e Vet. UNESP, 14870-000 Jaboticabal Depto. de Patologia Veterinaria Faculdade de Cienc. Agrarias e Vet. UNESP, 14870-000 Jaboticabal