Antigenic characterization of an abnormal isoform of prion protein using a new diverse panel of monoclonal antibodies.

We established a panel of monoclonal antibodies (mAbs) against prion protein (PrP) by immunizing PrP gene-ablated mice with the pathogenic isoform of prion protein (PrPSc) or recombinant prion protein (rPrP). The mAbs could be divided into at least 10 groups by fine epitope analyses using mutant rPrPs and pepspot analysis. Seven linear epitopes, lying within residues 56-90, 119-127, 137-143, 143-149, 147-151, 163-169, and 219-229, were defined by seven groups of mAbs, although the remaining three groups of mAbs recognized discontinuous epitopes. We attempted to examine whether any of these epitopes are located on the accessible surface of PrPSc. However, no mAbs reacted with protease-treated PrPSc purified from scrapie-affected mice, even when PrPSc was dispersed into a detergent-lipid protein complex, to reduce the size of PrPSc aggregates. In contrast, denaturation of PrPSc by guanidine hydrochloride efficiently exposed all of the epitopes. This suggests that any epitope recognized by this panel of mAbs is buried within the PrPSc aggregates. Alternatively, if the corresponding region(s) are on the surface of PrPSc, the region(s) may be folded into conformations to which the mAbs cannot bind. The reactivity of a panel of mAb also showed that the state of PrPSc aggregation influenced the denaturation process, and the sensitivity to denaturation appeared to vary between epitopes. Our results demonstrate that this new panel of well-characterized mAbs will be valuable for studying the biochemistry and biophysics of PrP molecules as well as for the immuno-diagnosis of prion diseases.

[Investigative evaluation of mass screening for cancer of the cervix uteri by automobile in two periods (1974-1983 and 1984-1993) in Fukui Prefecture].

OBJECTIVE: The study was carried out to analyse and compare the number of examinees, cancer detection rate change in the age distribution of screened women with data from the periods 1974-1983 and 1984-1993. SUBJECTS AND METHODS: The target population of the study composed women participating in uterine cancer screening by automobile in Fukui prefecture over the twenty year from 1974 to 1993, divided equally into early and late periods. The examination method was smear sampling for cytology, performed by scraping the cervix with a cotton swab or wooden spatula. Patients with suspicious or positive smears underwent histological diagnosis by colposcopic biopsy. RESULTS: 1) The number of examinees was increased over 160% during the late as compared to the early periods. 2) The dysplasia detection rate increased from 0.195 to 0.27%. 3) The carcinoma detection rate, in contrast, decreased from 0.2% to 0.1%. 4) The rate of smears categorized as class III or above increased with age in the early period but was steady across the age distribution in the late period. 5) Class (IIIa) dysplasia and class (IIIb) in situ carcinoma detection rates were higher in the late than the early period. 6) The carcinoma detection rates increased with age in early period, while in the late period, those for patients under the age of 29 and over 70 years old were higher and these for other ages were lower than in the early period. 7) The carcinoma detection rate for first examinees was higher than for repeated examinees. 8) The proportion of first examinees was 65.5% among women under the age of 29 and 46.8% among women aged 30-34. 9) Carcinoma detection rates for individual public health centers (PHCs) were Fukui PHC 0.13%, Kanazu PHC 0.11%, Okuetsu PHC 0.09%, Tannan PHC 0.11%, Reinan PHC 0.04%. CONCLUSIONS: The results showed the detection rate to be higher at the first visit. The detection rates for dysplasia and carcinoma were increased in young women in the late as compared to the early period. It is important to follow up the patients with dysplasia and encourage more frequent visit by young as well as aged women.