Differential expression of ovine CD1

was examined using a combination of reverse transcription-polymerase chain reaction (RT-PCR) with sequence-specific primers and Northern and in situ hybridization techniques. The aim of the study was to establish the patterns of CD1 expression at the molecular level and address questions posed by previous studies in other species regarding expression patterns of CD1. A 'pan-CD1' probe based on the exon 4 (alpha 3) region was used in addition to isotype-specific probes for SCD1B (the exon 3 region of clone SCD1B42) and SCD1D (the exon 3 region of clone SCD1D). Widespread expression of CD1 (including thymus, peripheral blood lymphocytes, lung and intestine) was identified using both the exon 4 and SCD1D probe. SCD1B expression was more restricted, being identified in equivalent levels only in the thymus and in scattered populations of dendritic cells. These results highlight the difference in expression patterns between group 1 and group 2 CD1 family members and establish SCD1D as the CD1 family member with the widest pattern of expression, consistent with a differential role for the different CD1 family members.