The presence of cytotoxic autoantibody to lacrimal gland cells in NZB/W mice

New Zealand Black and White F₁ hybrid mice (NZB/W mice) spontaneously develop in autoimmune disease which provides us with a suitable animal model for Sjogren's syndrome. With increasing age, these mice develop foci of mononuclear cell infiltration in the lacrimal and salivary glands, which closely resemble the lesions seen in patients with Sjogren's syndrome. We studied the cell-mediated and antibody-mediated immune responses of NZB/W mice to lacrimal gland cells. Lacrimal gland acinar cells were isolated from 2-month-old NZB/W or BALB/c mice for the target of ⁵¹Cr-release assay. There was no statistically significant difference in the spleen cell-mediated cytotoxicity to lacrimal gland cells among NZB/W mice of different ages (2, 5, and 8 months old). With increasing age, on the other hand, we found a statistically significant increase in the titers of autoantibodies to lacrimal gland cells in NZB/W mice, while aged BALB/c mice did not develop such antibodies. Fractionation of pooled positive sera by gel filtration revealed that this cytotoxic activity was mostly recovered in the IgM fraction. The tissue absorption study showed that these antibodies cross-reacted with salivary gland and kidney.