Galectin-9 recognizes and exhibits antimicrobial activity toward microbes expressing blood group–like antigens

Abstract

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ABO blood group antigens and differential glycan expression: Perspective on the evolution of common human enzyme deficiencies

“…There is uncertainty as to the origin of so called “natural antibodies.” Conflicting data exist regarding the potential role of plant materials, microbes, genetic elements, and even transient blood group A and B expression, in the development of naturally occurring antibody formation, in general, and formation of anti-ABO(H) antibodies, in particular ( Bernstein, F., 1925 , F S, 1934 ; Furuhata, 1969 ; Hayakawa et al., 1999 ; New et al., 2020 ; Springer, 1956 ; Springer et al., 1961 ; Storry and Olsson, 2009 ; Wagner, 1955 ; Watkins, 2001 ). Innate immune factors appear to specifically target microbes decorated in blood group carbohydrate antigens ( Arthur et al., 2015b ; Blenda et al., 2022 ; Ho et al., 2022 ; Stowell et al., 2010 , 2014 , 2014 ; Wu et al., 2021b , 2022 , 2022 ), suggesting that a unique interplay may exist between blood group positive microbes, innate immunity, and the development of naturally occurring anti-blood group antibodies. However, studies using germ-free mice suggest that exogenous antigen stimulation is not required for naturally occurring antibody formation ( Bos et al., 1989 ; Bunker et al., 2017 ; Haury et al., 1997 ; Hooijkaas et al., 1984 , 1985 ).…”

An Automated Approach to Assess Relative Galectin-Glycan Affinity Following Glycan Microarray Analysis

“…To achieve this, we utilized an open-source programming language, Python 3, which offers the most substantial flexibility in time complexity and data structure. The output of the program includes general RFU graphs for each dilution, curve-fitting graphs for each sample, and calculated B max , K D , K A, and % max binding for unsaturated glycan ligands in a spreadsheet file using the same approach as outlined previously ( Blenda et al, 2022 ; Wu et al, 2021 ).…”

“…Thus, using this approach, more accurate assessments of binding affinity can be obtained. Importantly, using this approach, predictions regarding glycan binding specificity have accurately predicted actual glycan binding to cell surface glycans, providing important insight into previously unrecognized activities of a given galectin ( Stowell et al, 2008a ; Blenda et al, 2022 ).…”

“…Human galectin was expressed and stored as outlined previously ( Wu et al, 2021a ; Paul et al, 2022 ). Six previously published human galectin datasets, human Gal-3, Gal-3C, Gal-7, Gal-9, Gal-9N, and Gal-9C ( Wu et al, 2021b PMID:35754739; Blenda et al, 2022 ), were used to evaluate the performance of kdMining and kaPlotting. Each purified galectin was directly labeled with Alexa Fluor™ 488 NHS Ester (Invitrogen) per manufacturer instructions.…”

Innate immune Galectin-7 specifically targets microbes that decorate themselves in blood group-like antigens

“…Labeled Gal-3 or Gal-7 were purified again by lactosyl-sepharose column to remove possible inactive protein that may have formed during labeling process. Bound Gal-7 was eluted with 100 mM lactose in PBS plus 2-mercaptoethanol (2-ME) and then a PD-10 gel filtration column was used to remove 2-ME and lactose prior to the use of Gal-7 for experiments ( Blenda et al., 2022 ; Stowell et al., 2007 , 2008b ; Wu et al., 2021b , 2021c ). The molecular weight of monomeric Gal-7 is 15 kDa.…”