Polymeric IgA is superior to monomeric IgA and IgG carrying the same variable domain in preventing Clostridium difficile toxin A damaging of T84 monolayers

H Stubbe, J Berdoz, JP Kraehenbuhl… - The Journal of …, 2000 - journals.aai.org
H Stubbe, J Berdoz, JP Kraehenbuhl, B Corthésy
The Journal of Immunology, 2000journals.aai.org
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 …
Abstract
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 (IgA d/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 IgA d/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 IgA d/p specific for both toxins in the lamina propria.
journals.aai.org