The outer membrane protein (OMP) and its fractions (OMP₁~OMP₅) of B. pertussis were obtained through Triton X-100 treatment and Sephadex G-100 column chromatography. OMP₁~OMP₄ had LP, HS and IAP activities. The OMP and its fractions exhibited cytotoxity to CHO cells such as clustered growth, inhibition of ³H-TdR incorporation, falling of the ribosomes and reduction of the juxtamembranous particles. The activities of LP, HS, IAP and CHO cell clustered growth decreased obviously after glutaraldehyde detoxification. The ³H-TdR incorporation of CHO cells in the presence of the detoxified fractions was much higher than that of the non-detoxified ones, and not differed significantly from the black controls (P>0.05). There were io significant differences among the actively protective activities in mice of the non-detoxified and the detoxified fractions (P>0.05). The results showed that the toxicities of the fractions (OMP₁~OMP₄) declined obviously after treatment with 0.3% glutaraldehyde while the detoxified fractions still possessed strong antigenicities and protective activities. Thus, the OMP and its fractions after glutaraldehyde detoxification might be adopted as acellular vaccine of B. pertussis.