In vivo Priming of TNP-reactive Effector Cells in Carp.

Abstract

ABSTRACT-In a study of immune mechanisms in fish, specific cell-mediated cytotoxic activity against trinitrophenyl (TNP)-modified autologous peripheral blood leucocytes (PBL) was success fully induced in in vivo primed carp Cyprinus carpio. The cytotoxic activity increased in proportion to the number of immunizations. The cytotoxic activity was shown to be gradually reduced with time after in vivo sensitization, and was finally lost. In addition, cytotoxic activities against TNPmodified allogeneic PBLs (T-ALLO-PBL) in carp immunized with TNP-modified autologous PBLs (T-AUTO-PBL) were not detected and effector cells from carp immunized with T-ALLO-PBL were not significantly cytotoxic against T-AUTO-PBL. Thus, the occurrence of a genetic restriction in carp was shown using the in vivo priming model. These results suggest that specific cell-mediated cytotoxicity of in vivo primed carp in some respects resembles mammalian cytotoxic T cells.

Characterization of the cell-mediated cytotoxic responses of isogeneic ginbuna crucian carp induced by oral immunisation with hapten-modified cellular antigens

“…The results of cold target inhibition studies provided further evidence for the syngeneic restriction of orally-induced cytotoxic cells. Additionally, in agreement with a previous report on common carp [17], oral administration of TNPmodified allogeneic cells failed to induce cytotoxic cells that could lyse TNP-modified syngeneic targets. These results strongly suggest that orally-induced cytotoxic cells are capable of recognizing hapten-modified target cells in an MHC-restricted manner.…”

“…Recent experiments have demonstrated that hapten-specific T cells recognize the haptenated peptides presented by MHC molecules on the surface of target cells [31,32]. As fish can elicit this type of immune reaction [16,17], we took advantage of the hapten-modified cellular antigens to analyse the nature of the effector cytotoxic cells generated by oral antigen administration. In the experiments described here we further characterized the orally-induced cytotoxic responses of fish, using clonal ginbuna crucian carp as an experimental model.…”

“…Previous studies demonstrated that cell-mediated cytotoxicity of common carp against TNP-modified targets was successfully induced by in vitro or in vivo immunisation with TNP-modified autologous cells and the effector cells did not show cross-reactivity against TNP-modified allogeneic targets [16,17]. To analyse whether the orally-induced cytotoxic responses against haptenated cells are MHC dependent, we next examined the reactivity against allogeneic targets.…”

Systemic priming of alloreactive cytotoxic cells in carp, following anal administration of allogeneic cell antigens

“…injection. The specific cell-mediated cytotoxic activity of carp and ginbuna crucian carp, induced by parenteral immunisation, reached a peak on days 4e7 after immunisation, and was reduced on days 10e21 after immunisation [22,26,30]. Thus, considering the requirement of resensitisation and in vivo kinetics of cytotoxic cells, the specific cell-mediated cytotoxicity induced by anal immunisation resembles that resulting from parenteral routes.…”

“…Fish received several booster administrations at 7-day intervals. This immunisation schedule was designed according to Hasegawa et al [22]. In some experiments, in order to compare anal administration with parenteral injection, fish were injected and boosted intraperitoneally with the suspension under the same conditions used in the anal administration.…”