Faculty Bibliography

Alloimmune T lymphocytes kill a wide spectrum of target cells, even in the absence of alloantigen recognition, providing that a lectin is incorporated into the assay medium. In these studies we have modified the lectin-dependent cell-mediated cytotoxicity (LDCMC) assay to evaluate the cytotoxic activity of canine T cells using a human B lymphoblastoid cell line (Raji) as the target. Canine peripheral blood mononuclear cells activated in vitro in mixed leukocyte cultures or by concanavalin A (Con A) killed 51Cr-labeled Raji target cells (up to 70% in 4 hr) when Con A was included in the assay. T cells expressed cytotoxic activity only when activated and when con A was present in the assay. Canine T cells activated in vivo also exerted cytotoxic activity in the LDCMC assay. T cells obtained from a rejecting allografted lung by bronchoalveolar lavage displayed considerably higher cytotoxic activity than did T cells obtained from the contralateral normal lung or peripheral blood of the same dog. In contrast, T cells from the lungs and blood of normal dogs and lung-allografted dogs without rejection exerted no cytotoxic activity. We conclude that the LDCMC assay using xenogeneic Raji cells as targets is a valid measure of the cytotoxic activity of canine T cells. Its major advantages include the fact that it is simple to perform and can be used when specific target cells are not available

Little is known about the traffic of lymphocytes within the lung and hilar lymph nodes and even less is known about the alterations in such traffic after immunization of animals via the trachea. To explore these phenomena, we developed an intrapulmonary immune response to alloantigens in mice by depositing semiallogeneic spleen cells into their tracheas. We studied lymphocyte traffic in this model by two assays. In one, we assessed the recruitment of nonspecific 51Cr-labeled resting lymphocytes to the lungs and hilar node and in the other, a dual-antigen, dual-isotope assay, we measured the recruitment of both allospecific and nonspecific labeled blast cells to the lungs and hilar nodes. The results indicated: (1) that circulating T lymphocytes that have recently synthesized DNA (blast cells) are retained in lungs and hilar lymph nodes of challenged mice far more readily than a circulating resting T lymphocytes, and (2) that there is at least some preferential retention of lymphocytes with specific reactivity to the alloantigen used for immunization. Although lymphocyte recruitment to the lungs and hilar nodes was observed during the entire 5-day postchallenge interval, most of the allospecific recruitment occurred during the first 48 hours