A novel method to display [gal alpha1, 3 gal] antigens on human leukemic cells for preparation of anti-leukemia vaccines.
BACKGROUND
Expression of the immunostimulatory xenoantigen alphaGal on malignant cells is being investigated as a means to formulate anticancer vaccines. Expression methods have been limited to gene transfer using viral vectors and enzymatic manipulation. We report here a novel method using polyethylene glycol (PEG) to induce plasma membrane fusion between malignant human hematological cells and alphaGal(+) porcine blood cells (PBC) in order to display alphaGal antigens on human cells.


METHODS
Freshly isolated white blood cells (WBC) were obtained from patients with malignant hematological disease and combined with diluted PBC. Cell mixtures were labeled with human CD mAbs, followed by IB4 lectin or M86 mAb to detect alphaGal antigens and then co-incubated with PEG. Back-gated, dual-color flow cytometry was used to detect alphaGal on human cells.


RESULTS
alphaGal antigens were detected on sizeable numbers of human WBC (approximately 45%) after incubation with PEG. Antigen expression was profuse as assessed by the strong fluorescent intensity demonstrated by IB4-FITC and M86 labeling. Human cells combined with PBC without PEG were not reactive with IB4-FITC or M86.


CONCLUSIONS
Our method provides an effective, highly reproducible means to efficiently express alphaGal antigens on cells obtained from patients with a spectrum of hematological malignancies. This method can provide a simple, safe alternative to viral-mediated gene transfer or enzymatic alteration to express alphaGal antigens on human tumor cells. By virtue of its simplicity, our technique presents a novel approach to the preparation of polyvalent autologous or syngeneic anticancer vaccines.
Posekany
Karla J
KJ
Department of Pediatrics, Medical Genetics, Brody School of Medicine, East Carolina University Greenville, Greenville, North Carolina 27834, U.S.A. Cutterpose@msn.com
Wiley
John E
JE
Gagnon
Gregory A
GA
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000276:immunology*; D019496:Cancer Vaccines / Q000276:immunology* / Q000627:therapeutic use; D004187:Disaccharides / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D037102:Lectins / Q000276:immunology; D007938:Leukemia / Q000276:immunology* / Q000628:therapy; D013552:Swine
D000911:Antibodies, Monoclonal; D019496:Cancer Vaccines; D004187:Disaccharides; D000939:Epitopes; D037102:Lectins; C055075:galactosyl-(1-3)galactose