Answer
deficent IgA lead to recurrent respiratory tract infections::
because IgA provide local immunity at mucous surfaces by
coating microorganisms - bacteria or viruses-
preventing their adherence to mucosal cells thus
preventing entry into body tissues.
so its abscence lead to easy entry of microorganisms into tissues
of respiratory tract leading to recurrent respiratory tract infection.
Work Step by Step
Secretory IgA
- is found in mucus secretions of the respiratory tract.
- it is dimeric , consisting of 2 monomer units joined by a short polypeptide chain called J chain.
- it is synthesized locally by submucosal plasma cells.
- as it passes to the lumen of the organ producing it
it aquires a " secretory piece " which is a polypeptide
synthesized by epithelial cells.
- the latter facilitates transport of secretory IgA into
secretions & protects it from being digested by
proteolytic enzymes .
- it provide local immunity at mucous surfaces by
coating microorganisms - bacteria or viruses-
preventing their adherence to mucosal cells thus
preventing entry into body tissues.
