RESUMO
The distribution of surface-exposed antigenic glycolipids in seven recent clinical isolates of Mycobacterium tuberculosis was established. Thin-layer and liquid chromatographies revealed a uniformity in the glycolipid pattern. Chemical analysis of the individual glycolipids of a selected strain enabled the identification of glycolipids of serological interest in all the other clinical isolates. Phenolic glycolipid-Tb1 (PGL-Tb1) was lacking in all strains, but appreciable amounts of a partially deglycosylated version (PGL-Tb1D) were present in the seven isolates. Diacyltrehaloses (DATs) were detected in all strains, showing themselves to be major glycolipids. Lipooligosaccharides (LOS-II) were present in the seven strains studied though only in trace amounts. These results shed new light on the open debate on the distribution of these interesting glycolipids in typical clinical isolates of M. tuberculosis. In the search for a serological test for tuberculosis, and in accordance with our observations, we believe that PGL-Tb1 and LOS-II should not be the target molecules for serology and that it is worthwhile to continue investigating the value of DATs as antigens. We also believe that it would be of interest to undertake research to assess the usefulness of PGL-Tb1D as an antigen.
Assuntos
Antígenos de Bactérias/análise , Glicolipídeos/análise , Mycobacterium tuberculosis/imunologia , Lipopolissacarídeos/análise , Mycobacterium tuberculosis/químicaRESUMO
A DOT-ELISA method for detection of 2,3-diacyl-trehalose (DAT, previously referred to as SL-IV antigen) and triglycosyl phenol phthiocerol di-mycocerosate (PGL-Tb1) antigens from Mycobacterium tuberculosis is described. The method enabled the detection of both antigens in 14 clinical isolates of M. tuberculosis from different geographic origins; the presence of the glycolipids was confirmed by chemical analysis. It was therefore concluded that the synthesis of both of these compounds is characteristic of the species.