Rapid and simple detection of a Mycobacterium tuberculosis circulating antigen in serum using dot-ELISA for field diagnosis of pulmonary tuberculosis.
Tuberculosis (TB) has re-emerged as a major health problem worldwide. Developing an easy, inexpensive immunodiagnostic test is extremely important for TB diagnosis, especially in developing countries. A target mycobacterial circulating antigen of 55-kDa molecular weight was identified in sera from confirmed Mycobacterium tuberculosis infected individuals by using Western blotting based on a specific mouse IgG anti-M. tuberculosis monoclonal antibody (TB-55 mAb). No bands were identified in sera of healthy individuals. The target TB antigen was isolated and characterized as a protein. It consists of 15 amino acids; 24.6% of the amino acids are hydrophobic and 46.4% are hydrophilic. A dot-ELISA format, based on TB-55 mAb, was developed for the direct demonstration of the 55-kDa TB antigen in serum samples of pulmonary TB patients. The technical aspects of the developed dot-ELISA are simple, rapid (5 min), and reproducible, as well as sensitive (87%) and specific (93%). Using the more sensitive immunoassay; Western blot, the 55-kDa TB antigen was detected in all (100%) sera that have been shown false negative by dot-ELISA, as well as in true positive sera. In conclusion, we have developed a simple and rapid immunoassay for the direct detection of a circulating mycobacterial antigen in sera of TB infected individuals and, therefore, the developed assay can be applied for laboratory and field diagnosis of TB infection in developing countries.
Attallah
Abdelfattah M
AM
Biotechnology Research Center, New Damietta City, Egypt. amattallah@hotmail.com
Abdel Malak
Camelia A
CA
Ismail
Hisham
H
El-Saggan
Abeer H
AH
Omran
Mohamed M
MM
Tabll
Ashraf A
AA
D000293:Adolescent; D000328:Adult; D000596:Amino Acids / Q000032:analysis; D000911:Antibodies, Monoclonal / Q000276:immunology; D000942:Antigens, Bacterial / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D012680:Sensitivity and Specificity; D012698:Serologic Tests; D014397:Tuberculosis, Pulmonary / Q000097:blood / Q000175:diagnosis*
D000596:Amino Acids; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial