Diagnosis of Bactec samples by immunoglobulins of mouse hyperimmune sera obtained against modified antigens of the cell wall of Mycobacterium tuberculosis

The objective: using double-site enzyme immunoassay (ELISA) to evaluate the specificity of the antigens of digestive and chemically modified cell walls (CW) of M. tuberculosis.

Subjects and methods. Hyperimmune sera of mice were obtained against modified CW antigens; immunoglobulins of different subclasses were isolated from them. With their help, 152 Bactec cultures with mycobacterial and non-mycobacterial growth from patients with lung diseases were tested by ELISA.

Results. When CW was treated with proteinase K (prK), the protein content decreased by 10 times, and upon hydrolysis of NaOH, by more than 30 times. In immunoblotting, there was a narrowing of the spectrum of recognized antigens by the sera of hyperimmune mice (compared with whole CW), which indicated a decrease in their immunogenicity. Modification of WC of M. tuberculosis disavows 54 kDa antigen, causing a strong IgG1 subclass response.

Diagnostic efficacy in ELISA with Bactec cultures increases with the use of immunoglobulins obtained against antigens treated with proteinase K – 79.14% (Pr.A) and 86.68% (Pr.G), when compared with immunoglobulins against the original drug – 70.69% (Pr.A) and 69.11% (Pr.G). Specificity increases significantly when using IgG1 antibodies after immunization with CW treated with prK (71.92% versus 25.93% in the initial preparation). Thus, new antigens of M. tuberculosis were identified, new antibody preparations for diagnosis in microbiological cultures were created against them.

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