Experimental bacterial keratitis: a quantitative model of leukocyte migration following transfusion.

A model for the study of polymorphonuclear leukocyte (PMN) migration after transfusion employing induction of keratitis in guinea pigs was developed. Initial studies demonstrated that compared with other agents, intracorneal injection of Pseudomonas aeruginosa following in vivo labelling of PMN by administration of 3H-thymidine produced the greatest influx of radiolabelled PMN into corneas. In subsequent studies, donor peritoneal PMN were radio-labelled by injection of donors with 3H-thymidine. Neutropenia was induced in recipients by whole body irradiation, and they were infected intracorneally with Pseudomonas prior to transfusion. Corneal radioactivity was assayed 24 h after induction of keratitis and the number of donor PMN in corneas was calculated. Half-life of transfused PMN in non-neutropenic recipients was 1.9 h. Arrival of labelled PMN at infected corneas in recipient animals ranged between 0.1-1.0% of transfused cells. Exposure of donor PMN to sonication or to 45 degrees C for 20 min reduced the proportion of PMN arriving at infected corneas (P less than 0.001). Storage of PMN for 24 h at 4 degrees C led to a greater ingress of donor PMN compared with storage at 37 degrees C (P less than 0.01). This model allows quantitation of in vivo PMN function after transfusion and should allow assessment of the effects of most aspects of PMN transfusion technique upon such function.