Abundance of NKT Cells in the Salivary Glands but Absence Thereof in the Liver and Thymus ofaly/alyMice with Sjِgren Syndrome

It is known that ALY/Nsc Jcl-aly/aly(aly/aly) mice that congenitally lack lymph nodes fall victim to Sjögren syndrome as a function of age. We investigated how TCRintcells of extrathymic origin and TCRhighcells of thymic origin are distributed in various organs of these mice. Although the distribution of T-cell subsets was not different between controlaly/+andaly/alymice in youth in any of the tested organs, the proportion of TCRintcells in the liver and spleen ofaly/alymice increased with aging. Usually, TCRintcells in the liver comprise a half-and-half mixture of a NK1.1+subset (i.e., NKT cells) and a NK1.1−subset. In constrast, almost all expanding TCRintcells in various immune organs ofaly/alymice were found to be NK1.1−. A large proportion of lymphocytes, including NK cells and TCRintcells, were also present in the salivary glands ofaly/alymice. Interestingly, these TCRintcells in the salivary glands contained an NK1.1+subset (i.e., NKT cells) that used an invariant chain of Vα14Jα281 for TCRαβ (>50%). Moreover, γδT cells that used Vγ 1, 2, 4/Vδ 1, 4, 6 mRNAs, different from those of γδT cells in the liver and intestine, were abundant. Possibly reflecting thein situgeneration of these T cells in the salivary glands, the expression of RAG-2 mRNA was evident by the RT-RCR method. These results suggest that (i) inflammatory lymphocytes that evoke Sjögren syndrome inaly/alymice are NK cells or TCRintcells (both NK1.1+and NK1.1−subsets) and (ii) TCRintcells in the salivary glands might be generatedin situ.