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Experimental bacterial keratitis: a quantitative model of leukocyte migration following transfusion
Abstract:
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.
Insights
This study developed a guinea pig model to track polymorphonuclear leukocyte (PMN) migration after transfusion. The model quantifies PMN function, revealing that storage conditions significantly impact their ability to reach infected corneas.
Area of Science:
- Immunology
- Transfusion Medicine
Background:
- Polymorphonuclear leukocytes (PMNs) are crucial for immune response.
- Understanding PMN migration post-transfusion is vital for optimizing therapeutic outcomes.
- Existing models may not fully capture in vivo PMN function after transfusion.
Purpose of the Study:
- To develop and validate a novel animal model for studying polymorphonuclear leukocyte (PMN) migration following transfusion.
- To quantify the in vivo function of transfused PMNs in an experimental keratitis model.
- To assess the impact of various pre-transfusion conditions on PMN homing to sites of infection.
Main Methods:
- Developed a guinea pig model of keratitis induced by Pseudomonas aeruginosa.
- Utilized in vivo radiolabelling of donor PMNs with 3H-thymidine for tracking.
- Induced neutropenia in recipients via whole-body irradiation prior to transfusion and infection.
- Assayed corneal radioactivity 24 hours post-infection to quantify donor PMN influx.
Main Results:
- The model successfully demonstrated radiolabelled PMN influx into infected corneas.
- Transfused PMNs exhibited a half-life of 1.9 hours in non-neutropenic recipients.
- PMN exposure to sonication or heat (45°C) significantly reduced their migration to infected corneas (P < 0.001).
- Storage of PMNs at 4°C for 24 hours resulted in greater PMN ingress compared to storage at 37°C (P < 0.01).
Conclusions:
- The developed guinea pig model provides a quantitative method for assessing in vivo PMN function after transfusion.
- Pre-transfusion handling and storage conditions significantly influence the efficacy of PMN transfusion.
- This model can be used to evaluate various aspects of PMN transfusion techniques and their impact on immune function.