A Specific Antigen Recovered from Tissue Infected with M. Paratuberculosis (Johne's Bacillus)

[摘要] The specific paratuberculosis antigen found in the intestinal mucosae of sheep with Johne's disease was further investigated.The antigen is quite resistant to low pH, but it is insoluble between approximately pH 3 and pH 5. Preliminary extraction of dried and ground mucosa at pH 4 to 4.5 will render subsequently prepared antigenic extracts more active, this is believed to be due to the removal of an inhibiting substance in the acid extract.No matter whether this preliminary extraction has been employed or not, it is best to carry out the antigenic extraction itself at about pH 9 and at 100 C, for one hour.As has previously been shown, a thorough mechanical grinding of the dried tissue is the most effective means of demasking the antigen in the mucosa. It was found that grinding in a ball-mill is much more effective than grinding by hand in a mortar. Also, that there is an optimum length of time that the tissue should be ground, since longer grinding again reduces the activity.

[学科分类] 生物科学（综合）