Specificity of Mycobacterium tuberculosis phenolic glycolipid (PGL-Tb1) antiserum.

The specificity of Mycobacterium tuberculosis anti-PGL-Tb1 antiserum prepared in rabbits was evaluated by an enzyme-linked immunosorbent assay. It was found that the antiserum immunoreacted with its homologous antigen but not with purified phenolic glycolipids from M. bovis BCG (mycoside B), M. kansasii (mycoside A), M. leprae (PGL-I) or M. marinum (mycoside G). The analysis of chloroform/methanol extracts from 15 strains of M. tuberculosis showed that all formed the antigen except the type strain (strain H37Rv). Chloroform/methanol extracts of M. bovis BCG, M. xenopi, M. flavescens and M. fallax cross-reacted with the immune serum. However, chloroform/methanol extracts of representative strains of 18 other mycobacterial species did not react, therefore indicating that these did not contain the antigen.