Faculty Bibliography

Three cases of arterial-graft infection are presented. In all cases the gram stain obtained at surgery demonstrated white blood cells but no bacteria. Cultures obtained at operation subsequently grew Pseudomonas aeruginosa in two patients and Bacteroides fragilis in one patient. Failure to recognize the fallibility of the gram stain in the diagnosis of vascular infection may result in incorrect management decisions

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