03598nas a2200421   4500000000100000008004100001260001300042653001000055653000900065653001200074653002600086653002400112653003800136653003200174653001100206653001600217653001100233653002100244653001200265653000900277653001600286653002500302653001600327100001600343700001500359700001500374700001500389700001500404700001700419700001600436245013700452856005900589300001200648490000700660050003200667520246300699022001403162       1992                            d  c1992 Sep10aAdult10aAged10aAnimals10aAntibodies, Bacterial10aAntigens, Bacterial10aEnzyme-Linked Immunosorbent Assay10aEvaluation Studies as Topic10aFemale10aGlycolipids10aHumans10aImmunoglobulin M10aleprosy10aMale10aMiddle Aged10aMycobacterium leprae10aPhilippines1 aDouglas J T1 aSteven L M1 aHirsch D S1 aFujiwara T1 aNelson K E1 aMadarang M G1 aCellona R V00aEvaluation of four semi-synthetic Mycobacterium leprae antigens with sera from healthy populations in endemic and non-endemic areas.  uhttp://leprev.ilsl.br/pdfs/1992/v63n3/pdf/v63n3a02.pdf  a199-2100 v63  aInfolep Library - available3 a<p>In order to determine the frequency of occurrence of antibodies to semisynthetic antigens of Mycobacterium leprae in clinically healthy nonpatient populations and to establish a 'baseline' for comparison with antibody frequencies in both patients with a history of leprosy and their contacts, ELISAs were conducted using representative sera from two areas: a leprosy endemic area, Cebu City, Philippines and a nonendemic area for leprosy Chicago, Illinois, USA. These sera were tested, by an indirect IgM ELISA, for the presence of antibodies reacting with four semisynthetic antigens based on the phenolic glycolipid I antigen of M. leprae: ND-O-BSA (natural disaccharide with octyl linkage to bovine serum albumin), NT-O-BSA (natural trisaccharide with octyl linkage to BSA), ND-P-BSA (natural disaccharide with phenolic ring linkage to BSA) and NT-P-BSA (natural trisaccharide with phenolic ring linkage to BSA). Using an OD reading > or = 0.16 as positive, the antigen with the lowest background seroreactivity was ND-O-BSA, which reacted with 5/398 (1.3%) sera from Cebu, and 3/426 (0.7%) sera from Chicago. A total of 10 (2.5%) of 398 sera from the endemic area reacted with at least one antigen and 5 (1.3%) sera reacted with all four semisynthetic antigens. Of the 426 sera from Chicago, 12 (2.8%) were reactive with at least one antigen and 3 (0.7%) were reactive with all four semisynthetic antigens. Mean ELISA values for the 22 positive sera for each antigen ranged from 0.17 to 0.3 OD units, while the mean values for all sera in each area ranged from 0.01 to 0.04 OD units for all four antigens. Reactivity of 14 of the positive sera to some antigens, but not all four semisynthetic antigens, indicated that the carrier and linker arms might be associated with this background reactivity. Investigation of alternative linker arms and carriers is warranted. We conclude that nonspecific background reactivity to the semisynthetic antigens representing the PG-I molecule of M. leprae is 0.7-1.3%, based on a > or = 0.16 OD cutoff value. From these data it was concluded that reactivity in individuals free of leprosy was low enough to warrant use of these antigens in a diagnostic setting, such as screening household contacts and highly endemic populations. When incidence and prevalence of leprosy are low, testing with these antigens would not be cost effective, unless applied to high risk individuals.(ABSTRACT TRUNCATED AT 400 WORDS)</p>  a0305-7518