The cellular immune recognition of proteins expressed by an African swine fever virus random genomic library

The cellular immune recognition of peptides expressed by an African swine f ever virus (ASFV) random genomic Library has been studied. DNA from the Mal awi (LIL20/1) ASFV isolate was randomly sheared by sonication, cloned into a plasmid vector downstream of a bacteriophage T7 promoter, and 72 recombin ant plasmids were arbitrarily selected. These plasmids were transiently exp ressed following transfection into major histocompatibility complex (MHC) c lass I+ class II- matched pig skin cells, which had been co-infected with v TF7-3, a recombinant vaccinia virus encoding bacteriophage T7 RNA polymeras e. Such cells served as antigen presenting cells and each recombinant plasm id was screened in a proliferation assay for recognition by CD8(+) lymphocy tes from inbred pigs previously exposed to ASFV. This assay was demonstrate d to measure CD8(+) T cell proliferation, as predicted by the phenotype of the antigen presenting cell. Of the 72 randomly selected clones, 14 were re producibly recognised by immune pig lymphocytes and 10 corresponded to non- overlapping and distinct nucleic acid sequences. This high frequency of ASF V encoded antigenic epitopes supports the concept that cellular immunity to the virus may play an important role in resistance to ASF. (C) 2000 Elsevi er Science B.V. All rights reserved.