Role of secretory immunoglobulin A and secretory component in the protection of mucosal surfaces

2010 ◽  
Vol 5 (5) ◽  
pp. 817-829 ◽  
Author(s):  
Blaise Corthésy
Keyword(s):  
Immunoglobulin A ◽  
Secretory Component ◽  
Secretory Immunoglobulin A ◽  
Mucosal Surfaces ◽  
Secretory Immunoglobulin

scholarly journals Structural insights into secretory immunoglobulin A and its interaction with a pneumococcal adhesin

2020 ◽  
Author(s):  
Yuxin Wang ◽  
Guopeng Wang ◽  
Yaxin Li ◽  
Hao Shen ◽  
Huarui Chu ◽  
...  
Keyword(s):  
Specific Interaction ◽  
Immunoglobulin A ◽  
Underlying Mechanism ◽  
Secretory Component ◽  
Secretory Immunoglobulin A ◽  
Immunoglobulin Receptor ◽  
J Chain ◽  
Cryo Electron Microscopy ◽  
Structural Insights ◽  
Secretory Immunoglobulin

AbstractSecretory Immunoglobulin A (SIgA) is the most abundant antibody at the mucosal surface. SIgA possesses two additional subunits besides IgA: the joining chain (J-chain) and secretory component (SC). SC is the ectodomain of the polymeric immunoglobulin receptor (pIgR), which functions to transport IgA to the mucosa. The underlying mechanism of how the J-chain and pIgR/SC facilitates the assembly and secretion of SIgA remains to be understood. During the infection of Streptococcus pneumoniae, a pneumococcal adhesin SpsA hijacks SIgA and unliganded pIgR/SC to evade host defense and gain entry to human cells. How SpsA specifically targets SIgA and pIgR/SC also remains unclear. Here we report a cryo-electron microscopy structure of the Fc region of human IgA1 (Fcα) in complex with J-chain and SC (Fcα-J-SC), which reveals the organization principle of SIgA. We also present the structure of Fcα-J-SC in complex with SpsA, which uncovers the specific interaction between SpsA and human pIgR/SC. These results advance the molecular understanding of SIgA and shed light on the pathogenesis of S. pneumoniae.

Column enzyme immunoassay for secretory immunoglobulin A in serum.

1983 ◽  
Vol 29 (1) ◽  
pp. 151-153 ◽  
Author(s):  
R Yamamoto ◽  
S Kimura ◽  
S Hattori ◽  
Y Ishiguro ◽  
K Kato
Keyword(s):  
Enzyme Immunoassay ◽  
Sodium Carbonate Solution ◽  
Solid Phase ◽  
Immunoglobulin A ◽  
Enzyme Reaction ◽  
Secretory Component ◽  
Secretory Immunoglobulin A ◽  
Serum Samples ◽  
Sepharose 4B ◽  
Secretory Immunoglobulin

Abstract This enzyme immunoassay for specific measurement of secretory immunoglobulin A concentrations in human serum involves use of a small chromatographic column as a solid-phase. Serum samples are incubated for 2 h with beta-D-galactosidase-labeled antibody to secretory component, then passed through a 0.1-mL Sepharose 4B column containing antibodies to human immunoglobulin A. After the column is washed to remove the unbound label, the buffer in the column is replaced by a solution of o-nitrophenyl-beta-D-galactoside (a beta-D-galactosidase substrate) and incubated at 25 degrees C overnight. The enzyme reaction is stopped by washing the column with sodium carbonate solution, and the absorbance of the eluate is measured at 420 nm. The concentration of secretory immunoglobulin A can be determined with a minimum detectable sensitivity of 3 mg/L, without interference from free immunoglobulin A and secretory component in the same samples.

scholarly journals Cleavage of the Human Immunoglobulin A1 (IgA1) Hinge Region by IgA1 Proteases Requires Structures in the Fc region of IgA

2003 ◽  
Vol 71 (5) ◽  
pp. 2563-2570 ◽  
Author(s):  
Koteswara R. Chintalacharuvu ◽  
Philip D. Chuang ◽  
Ashley Dragoman ◽  
Christine Z. Fernandez ◽  
Jiazhou Qiu ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Pathogenic Bacteria ◽  
Immunoglobulin A ◽  
Secretory Immunoglobulin A ◽  
Constant Region ◽  
Wild Type ◽  
Mucosal Surfaces ◽  
Secretory Immunoglobulin

ABSTRACT Secretory immunoglobulin A (IgA) protects the mucosal surfaces against inhaled and ingested pathogens. Many pathogenic bacteria produce IgA1 proteases that cleave in the hinge of IgA1, thus separating the Fab region from the Fc region and making IgA ineffective. Here, we show that Haemophilus influenzae type 1 and Neisseria gonorrhoeae type 2 IgA1 proteases cleave the IgA1 hinge in the context of the constant region of IgA1 or IgA2m(1) but not in the context of IgG2. Both Cα2 and Cα3 but not Cα1 are required for the cleavage of the IgA1 hinge by H. influenzae and N. gonorrhoeae proteases. While there was no difference in the cleavage kinetics between wild-type IgA1 and IgA1 containing only the first GalNAc residue of the O-linked glycans, the absence of N-linked glycans in the Fc increased the ability of the N. gonorrhoeae protease to cleave the IgA1 hinge. Taken together, these results suggest that, in addition to the IgA1 hinge, structures in the Fc region of IgA are required for the recognition and cleavage of IgA1 by the H. influenzae and N. gonorrhoeae proteases.

scholarly journals Immunoglobulins to Group A Streptococcal Surface Molecules Decrease Adherence to and Invasion of Human Pharyngeal Cells

1998 ◽  
Vol 66 (3) ◽  
pp. 974-979 ◽  
Author(s):  
U. Fluckiger ◽  
K. F. Jones ◽  
V. A. Fischetti
Keyword(s):  
Streptococcal Infection ◽  
Immunoglobulin A ◽  
M Protein ◽  
Secretory Iga ◽  
Surface Molecules ◽  
Mucosal Surfaces ◽  
Group A ◽  
Specific Igg ◽  
Secretory Immunoglobulin

ABSTRACT The M protein is one of the most important virulence factors of group A streptococci (Streptococcus pyogenes) and may play an important role in the first steps of streptococcal infection. Since acute pharyngitis is a frequently occurring infectious disease caused by these bacteria, we wished to know whether antibodies to the M protein or other surface components inhibit adherence and internalization of streptococci to pharyngeal cells. We investigated the role of whole human secretory immunoglobulin A (sIgA), M6 protein-specific sIgA, and M6 protein-specific serum IgG in the inhibition of streptococcal adherence and internalization to cultured human pharyngeal cells. S. pyogenes D471, which produces a type 6 M protein (M+), and its isogenic M-negative (M−) derivative JRS75 were tested. Purified whole sIgA, M protein-specific sIgA, and sIgA preabsorbed with M protein were able to decrease significantly the adherence of streptococci to pharyngeal cells. Purified IgG against the M6 protein did not diminish the attachment of streptococci to the pharyngeal cells but did reduce internalization. Thus, our data suggest that secretory IgA may play a key role in preventing streptococcal infection at mucosal surfaces by blocking adherence while affinity-purified anti-M protein-specific IgG blocks epitopes responsible for invasion.

scholarly journals Cysteine Proteinases and the Pathogenesis of Amebiasis

2000 ◽  
Vol 13 (2) ◽  
pp. 196-206 ◽  
Author(s):  
Xuchu Que ◽  
Sharon L. Reed
Keyword(s):  
Critical Role ◽  
Immunoglobulin A ◽  
Chemotherapeutic Agents ◽  
Secretory Immunoglobulin A ◽  
Cysteine Proteinases ◽  
Intestinal Infection ◽  
Separate Species ◽  
Detailed Structural Analysis ◽  
Secretory Immunoglobulin

SUMMARY Amebiasis is a major cause of morbidity and mortality throughout the tropical world. Entamoeba histolytica is now recognized as a separate species from the morphologically identical E. dispar, which cannot invade. Cysteine proteinases are a key virulence factor of E. histolytica and play a role in intestinal invasion by degrading the extracellular matrix and circumventing the host immune response through cleavage of secretory immunoglobulin A (sIgA), IgG, and activation of complement. Cysteine proteinases are encoded by at least seven genes, several of which are found in E. histolytica but not E. dispar. A number of new animal models, including the formation of liver abscesses in SCID mice and intestinal infection in human intestinal xenografts, have proven useful to confirm the critical role of cysteine proteinases in invasion. Detailed structural analysis of cysteine proteinases should provide further insights into their biochemical function and may facilitate the design of specific inhibitors which could be used as potential chemotherapeutic agents in the future.

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