A 35-year-old woman with end-stage renal disease of unknown etiology is transplanted with a cadaver kidney. The patient develops oliguia shortly after transplantation and a renal biopsy shows immediate (hyperacute) rejection. Immunosuppression improves renal function. Which of the following represents the principle target for immune attack directed against this patient's allograft?
ABO antigens Bacterial antigens Glomerular basement membrane antigens b2-Microglobulin