Abstract: A Dot-Blot assay ("spot test") with Bis-N,N,dioctadecylamide (BDA.TDA) as antigen was developed to detect anti-BDA.TDA antibodies in tuberculosis patients. To develop the antigen-antibody reaction, as a first step and in order to enhance the reaction, an anti-human rabbit serum was used followed by incubation with a protein A-colloidal gold conjugate. This assay showed almost equal sensitivity and specificity as the .beta.-galactosidase ELISA test which was conducted in parallel. This simple and fast assay could be used in places where ELISA equipment is not easily available.

Abstract: A method of testing for tuberculosis and leprosy in animals or humans and antigens used in the method. The method involves carrying out an assay on sera from humans or animals using an antigen to bind antibodies in sera. The antigens used in the method are synthetic pseudo cord factor-like glycolipids having the structures (I) or (II) below: ##STR1## wherein R represents a straight or branched chain alkyl group having 15 to 18 carbon atoms. The antigens can be produced by chemical synthesis, and can therefore be made available in suitable quantities, and are relatively stable at ambient temperatures while showing good sensitivity and specificity for tuberculosis and leprosy. The antigens can be used, for example, for enzyme-linked immunosorbent assays, and related "spot tests" for diagnosing tuberculosis and leprosy.