The coupling of synthetic 3,6-di-O-methyl-β-D-glucopyranosyl-(1→4)-2,3-di-O-methyl-α-L-rhamnopyra nose, the hapten determinant of phenolic glycolipid I from Mycobacterium leprae, to bovine serum albumin (BSA) by reductive amination produced the antigen ε-N-1-[1-deoxy-2,3-di-O-methyl-4-O-(3',6'-di-O-methyl-β-D-glucopyranosyl )-rhamnitol]-lysyl-BSA, which proved highly sensitive in ELISA and showed good concordance with the native glycolipid in analysis of serum samples from 223 leprosy patients. Conjugates prepared from 6-O-methyl-β-D-glucopyranosyl- or β-D-glucopyranosyl-containing disaccharides were inactive and those containing noncyclic 3,6-di-O-methyl-glucitol showed little activity. Thus 3,6-di-O-methyl-β-D-glucopyranose in its cyclic hemiacetal form is necessary for binding anti-glycolipid IgM from leprosy patients. Analysis of serum samples from healthy subjects showed a false-positive rate of 2.4% (four of 169) against the glycolipid and 3.6% (six of 169) against the glycoconjugate. Comparable figures for samples of sera of tuberculosis patients were 3.0% (two of 66) and 9.0% (six of 66), respectively. Alternative synthesizing strategies may diminish this cross-reactivity. The prospects of a fully synthetic specific antigen for the worldwide serodiagnosis of leprosy look promising.
Bibliographical noteFunding Information:
Received for publication January 20, 1984, and in revised form May 15, 1984. This work was supported in part by contract NOI-AI-22682 from the National Institute of Allergy and Infectious Diseases. Please address requests for reprints to Dr. P. J. Brennan, Department of Microbiology, Colorado State University, Fort Collins, Colorado 80523. "Present address: Laboratory of Chemistry, Institute for Natura! Science, Nara University, Horaicho, Japan.
All Science Journal Classification (ASJC) codes
- Immunology and Allergy
- Infectious Diseases