LYMPH-NODE HOMING CELLS BIOLOGICALLY ENRICHED FOR GAMMA-DELTA T-CELLSEXPRESS MULTIPLE GENES FROM THE T19 REPERTOIRE

Sheep gamma delta T cells have been shown serologically to express Tig , a membrane protein of 180-200 kDa which is a member of the scavenger receptor superfamily. Previous work from this laboratory resulted in the detection of a multigene family of T19-like genes in the sheep gen ome. In this study nucleotide sequences from several T19 genes were de termined and are reported along with the corresponding segments of a n umber of expressed mRNA molecules. A segment of a single sheep T19-lik e gene was sequenced and these data, along with the corresponding sequ ences from cloned T19-like cDNA molecules from sheep and cow, were use d to design an oligonucleotide primer system suitable for amplificatio n of corresponding segments of many T19 genes and their cDNAs. Between 30 and 40% of cloned T19 genes were amenable to amplification using t he selected primers, and sequence analysis of cloned PCR products conf irmed that different T19 genes encode unique amino acid sequences. The expression of multiple T19 genes was established using cDNA molecules obtained from a single sample of sheep lymphocyte mRNA. The possible role of the T19 family of genes is discussed.