title: Identification of antibody responses to Mycobacterium tuberculosis antigens in the CSF of tuberculous meningitis patients by Western blotting.
abstract: One of the adjunctive modes of diagnosing tuberculous meningitis (TBM) is to detect immune responses in the cerebrospinal fluid (CSF) to the Mycobacterium tuberculosis antigen. Up to 70% of clinical TBM reveal the presence of antimycobacterial antibody by the enzyme-linked immunosorbant assay. Defining the specificity of this immune response by Western blotting on separated M. tuberculosis antigen has been attempted in this study. Only antimycobacterial antibody-positive TBM cases were included in the study. An analysis of 30 such TBM cases showed a major immune reactivity to the 30- to 40-kDa region (93%) while a lower degree of immune reactivity was seen to the 14-kDa region (87%) and to the 18- to 25-kDa region (60%). Grossly the antibody reactivity on Western blot correlated with the ELISA results. Assessment of antimycobacterial antibody in the neurologic control CSF samples of pyogenic meningitis [n = 10], cryptococcal meningitis [6], neurocysticercosis [28], neurosyphilis [8], viral meningoencephalitis [8], carcinomatous meningitis [8], iatrogenic meningitis [6], and nonneurological control CSF samples from patients undergoing spinal anesthesia [20] revealed the presence of antibody in the CSF of 2 of the 10 pyogenic meningitis and 5 of the 28 neurocysticercosis cases. A Western blot analysis of these 7 cases revealed immune reactivity to 30- to 40-kDa regions only in 2 cases (1 of pyogenic and 1 of neurocysticercosis). The remaining 5 CSF samples did not reveal any immune reactivity on Western blotting, although ELISA demonstrated antimycobacterial antibodies. The antibody response to M. tuberculosis lipoarabinomannan and 38-kDa antigen by ELISA revealed 70.58 and 41.17% positivity, respectively. Thus this study has demonstrated that, by Western blotting, the major immune response is to the 30- to 40-kDa region, namely, lipoarabinomannan. Further, this finding will be useful for specific immunodiagnosis of the TBM.
authors.affiliation: Department of Microbiology, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors.forename: S A
authors.initials: SA
authors.lastname: Patil
authors.forename: M
authors.initials: M
authors.lastname: Gourie-Devi
authors.forename: J R
authors.initials: JR
authors.lastname: Chaudhuri
authors.forename: A
authors.initials: A
authors.lastname: Chandramuki
mesh_terms: D000907:Antibodies, Bacterial / Q000134:cerebrospinal fluid*; D000942:Antigens, Bacterial / Q000737:chemistry; D015153:Blotting, Western; D016022:Case-Control Studies; D003429:Cross Reactions; D006801:Humans; D007159:Immunologic Tests; D008070:Lipopolysaccharides / Q000737:chemistry / Q000276:immunology; D008581:Meningitis / Q000276:immunology; D008970:Molecular Weight; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D014390:Tuberculosis, Meningeal / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D008070:Lipopolysaccharides; C050016:lipoarabinomannan