Polymeric IgA is superior to monomeric IgA and IgG carrying the same variable domain in preventing Clostridium difficile toxin A damaging of T84 monolayers.
The two exotoxins A and B produced by Clostridium difficile are responsible for antibiotic-associated enterocolitis in human and animals. When added apically to human colonic carcinoma-derived T84 cell monolayers, toxin A, but not toxin B, abolished the transepithelial electrical resistance and altered the morphological integrity. Apical addition of suboptimal concentration of toxin A made the cell monolayer sensitive to toxin B. Both toxins induced drastic and rapid epithelial alterations when applied basolaterally with a complete disorganization of tight junctions and vacuolization of the cells. Toxin A-specific IgG2a from hybridoma PCG-4 added apically with toxin A alone or in combination with toxin B abolished the toxin-induced epithelial alterations for up to 8 h. The Ab neutralized basolateral toxin A for 4 h, but not the mixture of the two toxins. Using an identical Ab:Ag ratio, we found that recombinant polymeric IgA (IgAd/p) with the same Fv fragments extended protection against toxin A for at least 24 h in both compartments. In contrast, the recombinant monomeric IgA counterpart behaved as the PCG-4 IgG2a Ab. The direct comparison between different Ig isotype and molecular forms, but of unique specificity, demonstrates that IgAd/p Ab is more efficient in neutralizing toxin A than monomeric IgG and IgA. We conclude that immune protection against C. difficile toxins requires toxin A-specific secretory Abs in the intestinal lumen and IgAd/p specific for both toxins in the lamina propria.
Stubbe
H
H
Swiss Institute for Experimental Cancer Research, Epalinges, Switzerland.
Berdoz
J
J
Kraehenbuhl
J P
JP
Corthésy
B
B
D000918:Antibody Specificity; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000037:antagonists & inhibitors / Q000276:immunology / Q000633:toxicity*; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism; D016360:Clostridioides difficile / Q000276:immunology*; D004768:Enterotoxins / Q000037:antagonists & inhibitors / Q000276:immunology / Q000633:toxicity*; D004847:Epithelial Cells / Q000276:immunology* / Q000473:pathology; D006801:Humans; D007070:Immunoglobulin A / Q000502:physiology*; D007074:Immunoglobulin G / Q000494:pharmacology / Q000502:physiology*; D007135:Immunoglobulin Variable Region / Q000502:physiology*; D019108:Tight Junctions / Q000276:immunology / Q000473:pathology; D013997:Time Factors
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007135:Immunoglobulin Variable Region; C034639:polymeric IgA; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile