PHENOTYPE AND TCR-GAMMA-DELTA VARIABLE GENE REPERTOIRE OF INTESTINAL INTRAEPITHELIAL LYMPHOCYTES IN WILD MICE (MUS-MUSCULUS-DOMESTICUS) - ABUNDANCE OF V(GAMMA)1 TRANSCRIPTS AND EXTENSIVE DELTA-GENE DIVERSITY

In order to study murine intestinal intraepithelial lymphocytes (IEL) independent of factors imparted by conditions of laboratory housing an d breeding, and to provide a basis for comparison of IEL studies betwe en inbred and outbred mouse populations, IEL from the domestic house m ouse, Mus musculus domesticus, were analyzed by flow cytometric analys es using mAbs to murine lymphocyte markers, and by polymerase chain re action to study the TCR gamma and delta V gene repertoires. The majori ty of IEL in wild mice were CD3+, CD8+CD4- T cells. CD4+CD8- also were present in IEL isolates from wild mice, although at low numbers. Amon g IEL, but not T cells from the spleen or lymph nodes, there was a not able lack of Thy-1 expression, a preponderance of CD8alphaalpha+ T cel ls, and a relatively high ratio (3:1) of TCRgammadelta+ T cells over T CRalphabeta+ T cells, suggesting that some IEL in wild mice may develo p via an extrathymic pathway similar to that described for laboratory mice. Analyses of the IEL gamma and delta variable genes revealed rear rangements of three of six V region gamma genes (V(gamma)1, V(gamma)2, and V(gamma)5), with an abundance of V(gamma)1 transcripts as determi ned by Northern blot analyses. For the delta gene, rearrangement of fi ve of seven V region elements had occurred (V(delta)2, V(delta)3, V(de lta)4, V(delta)5, and V(delta)6). Sequence analyses of V - J and V - D - J junctional regions of cloned IEL gamma and delta genes revealed t hat at both the gene level and the protein level there was substantial ly more diversity for delta than gamma components of the IEL gammadelt a heterodimer, indicating a potential for interactions with polymorphi c structures by the delta chain. This study provides the first analyse s of IEL in mice independent of laboratory housing, breeding, and feed ing, and demonstrates that overall IEL in laboratory mice reflect what has been described for laboratory animals.