Cultivation of the exoerythrocytic stage of Plasmodium berghei in primary cultures of mouse hepatocytes and continuous mouse cell lines.

Plasmodium berghei exoerythrocytic (EE) stages have been cultured in vitro in human continuous cell lines and primary cultures of both human and rat hepatocytes. Although the predominant experimental model of irradiated sporozoite-induced protective immunity is the mouse, P. berghei has not been cultivated in primary mouse hepatocytes or in continuous mouse lines. Because of this, target cells are not available for determining if these immunized mice produce cytotoxic T lymphocytes (CTLs) that recognize P. berghei antigens expressed on hepatocytes in the context of class I major histocompatability (MHC) antigens. We report the development of methods for cultivating the (EE) stage of P. berghei in murine hepatocytes and in two cell lines derived from the livers of BALB/c mice; one line produced from a primary hepatocyte culture and the other produced by fusion of mouse hepatocytes with a continuous rat liver line. Mature parasites were detected by microscopy and by DNA probe in both cell lines, each of which supported complete development of P. berghei liver stages and production of infectious merozoites. Since class I MHC antigens are present on the surface of primary hepatocytes and the mouse X rat hybrid line, these cells can be used to detect cytotoxic T cells against liver stage parasites.