Expression of mouse Tla region class I genes in tissue enriched for γδ cells

The Tla region of the BALB/c mouse major histocompatibility complex contains at least 20 class I genes. The function of the products of these genes is unknown, but recent evidence demonstrates that some Tla region gene products could be involved in presentation of antigens to γδ T cells. We have generated a set of polymerase chain reaction (PCR) oligonucleotide primers and hybridization probes that permit us to specifically amplify and detect expression of 11 of the 20 BALB/c Tla region genes. cDNA prepared from 12 adult and fetal tissues and from seven cell lines was analyzed. In some cases, northern blot analysis or staining with monoclonal antibodies specific for the Tla-encoded thymus leukemia (TL) antigen were used to confirm the expression pattern of several of the genes as determined by PCR. Some Tla region genes, such as T24^d and the members of the T10^d/T22^d gene pair, are expressed in a wide variety of tissues in a manner similar to the class I transplantation antigens. The members of the TL antigen encoding gene pair, T3^d/T18^d, are expressed in only a limited number of organs, including several sites enriched for γδ T cells. Other Tla region genes, including T1^d, T2^d, T16^d, and T17^d, are transcriptionally silent from the T8^d/T20^d gene pair do not undergo proper splicing. In general, sites that contain γδ T lymphocytes have Tla region transcripts. The newly identified pattern of expression of the genes analyzed in sites containing γδ T cells further extends the list of potential candidates for antigen presentation to γδ T cells.