Study of respiratory symptoms among sputum positive

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covalent structure, a large number ofother complex materials are attached,
which are responsible for immunogencity and tuberculin activity ofwall
preparation. The most important of them are wax D., cord factor, sulfatides,
mycosides and poly. L. glutamic acid (Brennan, 1989).
Antigenic structure:
Mycobacteria contain many umque immuno-reactive substances,
most of which are components ofthe cell wall (Goren, 1982). In spite of
intensive study for more than 50 years the antigenic composition ofM. TB
is not clearly defined (young et al., 1985). Immuno - reactivity has been
demonstrated in lipids, polysaccharides and protein components. Since
protective immunity to mycobacterial infections is mediated primarily by
the cellular arm of the immune system proteins are regarded as the key
immunogens. Few antigens that compose this complex mosaic have been
obtained in chemically pure form to permit full evaluation of their
immunolgic potential (Edward and Kirkpatrick, 1986).
• The most common antigenic mycobacterial substances include:
1- Polysaccharides : The protein - free polysaccharides (arabinogalactans
and arabinomannans) are immunogenic and serologically active. The
significance of these humoral antibodies, however, has not been
established (Brennan, 1989).
2- Phosphatidyl Inositol Mannosides (PIMS) : These are a family of
amphipathic polar lipids, present in the plasma membrane of
..
_L mycobacteria and related organisms. They serve an important structural
role. There is renewed interest in these components, and a beliefthat
they are important lipoteichoic acid - like polymers with a role in
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