Secretory IgA

IgA Secretory IgA prevents attachment of bacteria and viruses to mucous membranes. Does not fix complement. 

Figure 50-10. Schematic representation of serum igA, secretory igA, and igM. Both igA and igM have a J chain, but oniy secretory igA has a secretory component. Poiypeptide chains are represented by thick iines disuifide bonds iinking different poiypeptide chains are represented by thin iines. (Reproduced, with permission, from ParslowTG et al [editors] Medical Immunology, 10th ed. McGraw-Hill, 2001.)...

The most widely studied therapeutic proteins produced in plants include monoclonal antibodies for passive immunotherapy and antigens for use as oral vaccines [40]. Antibodies against dental caries, rheumatoid arthritis, cholera, E. coli diarrhea, malaria, certain cancers, Norwalk virus, HIV, rhinovirus, influenza, hepatitis B virus and herpes simplex virus have been produced in transgenic plants. However, the anti-Streptococcus mutans secretory antibody for the prevention of dental caries is the only plant-derived antibody currently in Phase II clinical trials [40]. Until recently, most antibodies were expressed in tobacco, potato, alfalfa, soybean, rice and wheat [9], It has been estimated that for every 170 tons of harvested tobacco, 100 tons represents harvested leaves. A single hectare could thus yield 50 kg of secretory IgA [3, 41]. Furthermore, it has been estimated that the cost of antibody production in plants is half that in transgenic animals and 20 times lower than in mammalian cell cul-... 

Norwalk virus (NV) capsid protein Potato tuber tobacco leaf Mice and humans developed serum IgG and secretory IgA specific for recombinant NV. Immunogenic in mice and humans when administered orally. 45,57... 

Some research groups prefer IgAs because they are more stable than IgGs and more resistant to proteolysis. Plants can assemble secretory IgAs, which consist of... 

Goodman MR, Link DW, Brown WR, Nakane PK (1981) Ultrastructural evidence of transport of secretory IgA across bronchial epithelium. Am Rev Respir Dis 123(1) 115—119. 

Fig. 2. Diagram representing the comparative stmctures of secretory IgA and IgM. L, light chain H, heavy chain J, joining chain SC, secretory component. Reproduced by courtesy of the New England Journal of Medicine.

Wycoff, K.L. (2005). Secretory IgA antibodies from plants. Curr. Pharm. Des. 11(19) 2429-2437. 

The induction of an immune response by various mucosal routes is an important approach for the control of mucosally acquired infections. The apparent linked nature of the mucosal immune system enables the delivery of an antigen to any mucosal surface to have the secondary effect of potentially inducing immunity at others. Induction of a combination of systemic and secretory immune responses can be determined by the nature of the antigen, the route of administration, and the delivery system utilized. For example, traditional parenteral vaccines primarily induce IgM and IgG responses, whereas mucosal vaccination can elicit both IgG and secretory IgA responses (Corthesy, 2007). 

Corthesy, B. (2007). Roundtrip ticket for secretory IgA role in mucosal homeostasis J. Immunol. 178 27-32. 

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