THE IN-VITRO EXPRESSION PATTERNS OF INDIVIDUAL TYPE-I INTERFERON GENES IN NEWCASTLE-DISEASE VIRUS-INFECTED MURINE SPLENOCYTES AND FIBROBLASTS

Murine type I interferon levels present in mice sera following Newcast le disease virus infections are influenced by the If-1 locus. Sera int erferon levels in C57BL/6 mice (If-1(h) allele) are 10- to 15-fold hig her than in BALB/c mice (If-1(l) allele). The B6.C-H-28(c) strain, whi ch carries BALB/c If-1(l) allele on C57BL/6 genomic background, has lo w interferon levels in sera. This study examined the expression of int erferon alpha 1, alpha 4, alpha 5, alpha 6, alpha 9 and beta mRNAs at 7 hr after Newcastle disease virus infection of primary cells (splenoc ytes and mouse embryo fibroblasts) from C57BL/6, B6.C-H-28(c) and BALB /c mouse genotypes. Total RNA from these cells was reverse transcribed and all known type I interferon subtypes were amplified. The products were identified by differential hybridization to a panel of subtype s pecific oligonucleotides. The results show that the pattern of interfe ron subtypes examined in splenocytes did not differ between If-1(h) an d If-1(l) allele carrying C57BL mice. However, when the genotype was d ifferent (BALB/c splenocytes) the pattern of type I interferon mRNAs s een was altered. This genotype-dependent expression was also seen in N ewcastle disease virus infected fibroblasts. Within a given mouse stra in, there were also differences in the subtype response patterns detec ted in fibroblasts compared with those seen in splenocytes. In conclus ion, the present study indicates that mouse genotype appears to be a m ajor determinant of the subtype response pattern seen and tissue speci fic pattern differences are present within a given mouse genotype. (C) 1997 Elsevier Science Ltd.