ACKNOWLEDGEMENTS I would like to thank Dr. Paul Linser for both direction and yet ample latitude to explore and satisfy my own intellectual curiosities. I would also like to thank my committee comprised of Drs. Francis Davis, Carl Feldherr, and Chris West for guidance and constructive criticisms throughout my dissertation research. A special thanks goes to the University of Florida Division of Pediatric Hematology and Oncology and especially Dr. Adrian Gee for making this research possible through his commitment of continuous gifts of microspheres, antibodies, and encouragement to me. Also, I thank Dr. John Ugelstad of the University of Trondheim, Norway, for a generous gift of microspheres. I would also like to thank Drs. Gudrun Bennett and Gerry Shaw of the University of Florida as well as Dr. Steve Pfeiffer of the University of Connecticut for gifts of antibodies without which most of this work could not have been done. Thanks are also in order to Drs. Paul Begovac and Steve Dworetzsky for many worthwhile discussions and sharing the common bond of being a usually helpless guinea pig in the experiment of education that runs continuously and often without controls in the big orange and blue apparatus. I whole-heartedly thank anyone that I have left out that has made my time in graduate school either intellectually rewarding, pleasurable, or iii