ISCOM VACCINE AGAINST CONTAGIOUS BOVINE PLEUROPNEUMONIA (CBPP)1 - BIOCHEMICAL AND IMMUNOLOGICAL CHARACTERIZATION

A better vaccine than the existing ones against contagious bovine pleu ropneumonia (CBPP) caused by Mycoplasma mycoides subsp. mycoides small colony type (MmmSC) would improve the chances for eradication of CBPP . In such an effort, immunostimulating complexes (ISCOMS) have been pr epared from the whole detergent-solubilized cells of MmmSC and charact erized biochemically and immunologically. The most efficient detergent for solubilization of the mycoplasma was MEGA-10 which yielded a high recovery of proteins in the ISCOMS. The ISCOMS showed the typical cag e-like structure by EM and sedimented as 19S by sucrose gradient centr ifugation. The protein pattern of the ISCOMS, analyzed in SDS-PAGE, re vealed a great number of bands distributed along the gel as high and l ow molecular weight polypeptides. The Western blot developed with a se rum from a CBPP infected animal detected a reduced number of polypepti des. In samples from whole mycoplasma cells and in ISCOMS. lectin blot s revealed more than 20 carbohydrate structures. The ISCOMS induced a strong primary antibody response in mice measured by ELISA and the boo st resulted in a B-fold increase of the serum antibody response. The I gG response was distributed into various Ige subclasses with high IgG1 , IgG2a and IgG2b titres while the IgG3 response was low. In cattle th e ISCOM vaccine induced strong primary and long lasting secondary anti body responses of similar magnitudes as those of naturally infected an imals as recorded by ELISA which persisted mon than a year. IgG respon se was equally distributed in IgG1 and IgG2 subclasses. Also a cell-me diated immune response measured by proliferation assay was induced by low dose of ISCOMS. In the growth inhibition test, sera from vaccinate d cattle readily inhibited colony growth already after the first immun ization. (C) 1997 Elsevier Science B.V.