In vitro and in vivo effects of lymphokine-activated killer cells upon preattachment ovine conceptuses.

Abstract

An investigation assessed the cytolytic effect of autologous ovine lymphokine-activated killer (LAK) cells upon preattachment ovine conceptuses. For an in vitro experiment, conceptuses were recovered from six ewes on each of days 14, 16, and 19 (estrus = day 0). Dissociated conceptus cells (5 x 10(4), considered target cells) were incubated with autologous LAK cells at varying E:T ratios (5:1-200:1) and cytotoxicity was assessed by 51Cr release. In vivo, control (saline), cultured PBL (1 x 10(7)) and LAK cells (1- and 4- x 10(7)) were infused into the lumen of the uterine horn ipsilateral to the corpus luteum of mated ewes on day 14. Conceptuses were recovered on day 19 and placed within one of three morphologic categories (intact, large fragments, or highly fragmented). The numbers of mononucleated and binucleated giant cells and remaining trophoblastic cells were then quantitated within sections of conceptus tissue. Mitotic activity was also recorded. At E:T ratios of 100:1 and 200:1, respectively, percent 51Cr release for LAK cell cultures was greater (p < 0.05) for day-16 and 19- than day-14 conceptus cells. The frequencies of highly fragmented conceptuses recovered from saline + cultured PBL and LAK cell-infused ewes were 0/10 and 8/13, respectively. Within tissue sections, the numbers of morphologically normal mononucleated giant and mitotic cells were less (p < 0.05) for LAK cell (4 x 10(7)) than for saline-infused ewes. Data from additional in vitro and in vivo experiments revealed that supernatants from LAK cell (4 x 10(7)) cultures failed (p > 0.05) to affect % 51Cr release from K-562 target cells, conceptus morphology, and numbers of conceptus cells. In conclusion, autologous LAK cells exerted in vitro and in vivo lytic damage upon preattachment ovine conceptuses. A temporal pattern was observed for the in vitro lytic responses.