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Mycobacterium avium subspecies paratuberculosis (Map), the cause of ruminant paratuberculosis, has been proposed as the causative agent of Crohn's disease. The objective of this study was to determine whether exposure to clinical cases of bovine paratuberculosis was a risk factor for Crohn's disease. A questionnaire was sent to dairy farmers living on premises where the occurrence or absence of clinical cases of bovine paratuberculosis had previously been determined. The prevalence of Crohn's disease was found to be similar to that reported in other studies in the United Kingdom and showed no association with bovine paratuberculosis. There was, however, a univariate association with geographical region. Ulcerative colitis showed univariate associations with age, frequency of contact with cattle and with smoking. The results do not support the hypothesis that Map plays a causative role in the aetiology of Crohn's disease.

SUMMARY Collagens type I, II, III, IV, and V and the minor cartilage collagens, la 2a 3a, C-PS 1, and C-PS 2, were purified, antibodies raised, and then used in immunofluorescence studies on bovine nasal cartilage (BNC). Punctate This report describes the localisation of these collagens in BNC by immunofluorescence.Materials and methods Collagens. These were isolated from various bovine tissues after limited pepsin digestion. Type II, la 2a 3a, C-PS 1, and C-PS 2 collagens were isolated from adult nasal cartilage as described by Ayad et al.7 8 Types I and III collagen were prepared from placental membranes according to Epstein.' Types IV and V collagen were isolated from placental villi and membrane respectively by the method of Abedin et 575 on 11 May 2018 by guest. Protected by copyright.

Proliferative T cell responses to CII occur in some healthy individuals, suggesting that thymic tolerance for this antigen may be incomplete. Most patients with RA have no evidence of a T cell response to CII, possibly indicating the development of peripheral tolerance to this antigen as a consequence of cartilage breakdown. However, in a minority of patients, T and B cell responses to CII persist, and may contribute to joint damage.