Monoclonal antibody (MAb) WM-25 differentiates by in vitro growth inhibition Mycoplasma capricolum subsp. capripneumoniae (Mycoplasma strain F38), which causes contagious caprine pleuropneumonia, from other Mycoplasma spp. (F. R. Rurangirwa, T. C. McGuire, A. J. Musoke, and A. Kibor, Infect. Immun. 55:3219-3220, 1987). The antigen identified by MAb WM-25 was isolated from solubilized Mycoplasma strain F38 organisms by MAb WM-25 affinity chromatography and was stained with Schiff's reagent, but not with Coomassie blue, after separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Treatment of purified F38 polysaccharide with periodate abolished binding with MAb WM-25, and MAb WM-25 binding was blocked with laminarin, a complex oligosaccharide with ␤(133) sugar linkages. Purified F38 polysaccharide blocked both growth inhibition and agglutination of live F38 organisms caused by MAb WM-25 and rabbit antiserum to F38 organisms. The results in this paper demonstrate that MAb WM-25 binds a periodatesensitive epitope on the F38 polysaccharide which is also exposed on the surface of Mycoplasma strain F38. Because MAb WM-25 also causes in vitro growth inhibition of F38, the reactive polysaccharide epitope may induce protective immune responses.

Monoclonal antibody (MAb) E8-18 reacted with four isolates of Mycoplasma capricolum subsp. capripneumoniae in Western blots identifying an epitope on a 24 kDa antigen (p24). MAb E8-18 did not react with 11 isolates belonging to four other Mycoplasma species or subspecies closely related to M. capricolum subsp. capripneumoniae. A combination of trypsin treatment of intact organisms and detergent-phase partitioning revealed p24 to be an integral M. capricolum subsp. capripneumoniae surface membrane protein. Mycoplasma capricolum subsp. capripneumoniae, formerly designated Mycoplasma strain F38, is the causative agent of classical contagious caprine pleuropneumonia (CCPP) (31). The disease is of major economic importance in Africa and Asia and poses a major constraint to goat production because of high mortalities. M. capricolum subsp. capripneumoniae was originally isolated from a goat with pleuropneumonia in Kenya (30) and produces classical CCPP, which involves transmission by contact, high mortality, and a fibrinous pleuropneumonia characterized by massive hepatization and pleurisy (31). Whereas M. capricolum subsp. capripneumoniae has been isolated from goats in only seven other countries, including Sudan (19), Tunisia (33), Ethiopia (45), Chad (28), Oman (23), Turkey (47), and Uganda (4), it is not known whether the pleuropneumonia observed in other parts of the world is due to M. capricolum subsp. capripneumoniae or other mycoplasmas of the Mycoplasma mycoides cluster (9, 10, 14). The M. mycoides cluster includes seven Mycoplasma species: M. mycoides (small colony), M. mycoides (large colony), Mycoplasma capricolum subsp. capricolum, M. primatum, M. equigenitalium, Mycoplasma bovine group 7 described by Leach (26a), M. capri, and M. capricolum subsp. capripneumoniae (9, 10). All these organisms have extensive serological cross-reactivity (12-14, 24, 26) and biochemical similarities (1, 9, 10, 24, 26). The serological cross-reactivities have made it difficult to develop simple and yet specific diagnostic tests for the diseases caused by the different organisms. Various diagnostic tests have been reported, including latex agglutination (36), tests for monoclonal antibody (MAb) blocking and/or MAb reactivity with antigen in body fluids (44), dot blot immunobinding assay (18), and a combination of PCR and enzyme restriction analysis (5). Latex agglutination to detect serum antibodies to M. capricolum subsp. capripneumoniae is simple and can be performed in the field (36). The specificity of this test for field use is adequate; however, rabbit antisera to some other Mycoplasma species cause agglutination of M. capricolum subsp. capripneumoniae polysaccharide latex-coated beads, although these organisms