Characterization of mycobactserial antigens and anti-bodies in circulating immune complexes from pulmonary tuberculosis

Raja, A and Narayanan, P R and Mathew, R and Prabhakar, R (1995) Characterization of mycobactserial antigens and anti-bodies in circulating immune complexes from pulmonary tuberculosis. Journal of Laboratory and Clinical Medicine, 125. pp. 581-587. ISSN 0022-2143

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Abstract

Circulating immune complexes (CICs) in serum samples from patients with pulmonary tuberculosis (bacteriologically positive [S+C+] and bacteriologically negative [S-C-]) and controls (NHC) have been measured by using C1q binding assay (C1qBA) and 3.5% polyethylene glycol precipitation and measurement of absorbance at 280 nm (PEG-CD 280). Although C1qBA did not show any difference between tuberculous and normal serum samples, PEG-CD 280 was significantly elevated in tuberculous samples. The effect of chemotherapy on CIC levels was studied. During the treatment, initially (for up to 2 months) there was a rise in CIC levels and later a fail, coinciding with bacterial clearance. Anti-purified protein derivative antibodies of class immunoglobulin G (IgG) and immunoglobulin M were measured in the serum samples and PEG precipitates. Anti-mycobacterial antibody measurement in CICs was more discriminatory between the groups than serum antibody. For characterization of the complexed antibody, the PEG precipitates were used in the Western blot and the patterns were compared. S+C+ ClCs contained antibodies for a wide range of antigens ranging from 100 Kd to 10 Kd. However, none of the NHC-ClCs contained antibodies for antigens <70 Kd. Thus, when using the criterion of positivity for antibodies to antigens <70 Kd as a marker for pulmonary tuberculosis, 24 of 24 (100%) of the S+C+ CICs were positive. Similarly, 11 of 16 (70%) of the S-C- ClCs contained antibodies for antigens <70 Kd. The results are promising that measurement of complexed IgG for mycobacterial antigens of molecular weight <70 Kd might prove to be useful In accurately discriminating between the tuberculous patients and endemic normal subjects (100% sensitivity and 400% specificity). Moreover, the test can also be very useful in borderline positive (smear negative) cases, for which group diagnosis is very difficult. Such a test will be extremely useful in extrapulmonary and childhood tuberculosis, where early diagnosis is needed.

Item Type:	Article
Subjects:	Tuberculosis > Laboratory Research > Immunological
Divisions:	Basic Science Research > Immunology
Depositing User:	Dr. Rathinasabapati R
Date Deposited:	26 Sep 2013 06:40
Last Modified:	14 Mar 2016 05:28
URI:	http://eprints.nirt.res.in/id/eprint/389

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