Bacterial enzymes can add galactose alpha 1,3 to human erythrocytes and creates a senescence-associated epitope

R M Hamadeh, G A Jarvis, P Zhou, A C Cotleur, J M Griffiss
1996 Infection and Immunity  
Humans have abundant circulating anti-␣ (1,3-di)-galactosyl (␣Gal) antibodies (anti-Gal). Anti-Gal has been implicated in the clearance of senescent human erythrocytes (RBCs). The nature of the anti-Gal-binding RBC epitope has defied explanation, given that humans repress expression of the ␣1,3 galactosyltransferase (␣1,3 GT) enzyme. This study explored whether ␣Gal epitopes on human RBCs might be synthesized by ␣1,3 GTs of bacterial origin that are translocated into the circulation during
more » ... ulation during commensal colonization of the gut by gram-negative bacteria. We found that an acellular Klebsiella pneumoniae sonicate could add 3 H-UDP-Gal to human RBCs in the ␣ configuration at 37؇C in the presence of 6 mM MnCl 2 (pH 7.6). Gradient anion-exchange chromatography of the Klebsiella sonicate yielded four fractions that could catalyze the addition of 3 H-Gal to human RBCs. Size-exclusion chromatography of these anion-exchange fractions yielded peaks of high GT activity for each, but only those derived from the first, third, and last anion-exchange fractions incorporated Gal such that the RBCs bound anti-Gal by fluorescence-activated cell sorter, suggesting that these three GTs are ␣1,3 GTs. Thus, Klebsiella spp. make at least four GTs that can add an ␣Gal to human cell surface acceptor structures. Three of these GTs can form ␣1,3Gal structures on human RBCs that bind anti-Gal, thereby creating "autoimmune" senescence-associated RBC epitopes.
doi:10.1128/iai.64.2.528-534.1996 fatcat:bxnu67cydvcrdjna3mi7lwty6m