ABO血型的形成是一种自然免疫抑制的过程。在这项研究中，作者发现在肠道中表达的两个先天免疫凝集素（innate immune lectins）——半乳糖凝集素4（Gal-4）和半乳糖-8（Gal-8），能杀死表达血型抗原的大肠杆菌（E.Coli）,但对其他不表达血型抗原的细菌没有杀伤作用。这种杀死作用是通过C末端（C-terminal）结构域介导的，反应迅速，而且没有补体依赖性。
参考文献：Nat Med. 2010 Mar;16(3):295-301. Epub 2010 Feb 14.
Innate immune lectins kill bacteria expressing blood group antigen.
Stowell SR, Arthur CM, Dias-Baruffi M, Rodrigues LC, Gourdine JP, Heimburg-Molinaro J, Ju T, Molinaro RJ, Rivera-Marrero C, Xia B, Smith DF, Cummings RD.
Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA.
The expression of ABO(H) blood group antigens causes deletion of cells that generate self-specific antibodies to these antigens but this deletion limits adaptive immunity toward pathogens bearing cognate blood group antigens. To explore potential defense mechanisms against such pathogens, given these limitations in adaptive immunity, we screened for innate proteins that could recognize human blood group antigens. Here we report that two innate immune lectins, galectin-4 (Gal-4) and Gal-8, which are expressed in the intestinal tract, recognize and kill human blood group antigen-expressing Escherichia coli while failing to alter the viability of other E. coli strains or other Gram-negative or Gram-positive organisms both in vitro and in vivo. The killing activity of both Gal-4 and Gal-8 is mediated by their C-terminal domains, occurs rapidly and independently of complement and is accompanied by disruption of membrane integrity. These results demonstrate that innate defense lectins can provide immunity against pathogens that express blood group-like antigens on their surface (pages 263 -264).
PMID: 20154696 [PubMed - in process]