Development of specific lymphocyte immunostimulation and tuberculin skin reactivity in swine infected with Mycobacterium bovis and Mycobacterium avium

Swine infected with Mycobacterium bovis and Mycobacterium avium were studied for development and specificity of lymphocyte immunostimulation and tuberculin skin reactivity to purified protein derivatives (PPD) of tuberculins. Lymphocytes from infected animals had maximal blastogenic responses to PPD prepared from the homologous organisms. The time of appearance of specifically sensitized lymphocytes was studied, as was the specificity of skin reactivity. In vitro lymphocyte responses of M avium serotype 1-infected swine to M avium serotype 1 PPD were greater than were the responses of M avium serotype 2-infected swine to the same antigen. Results indicate that the specific stimulation of sensitized lymphocytes might prove useful in the diagnosis of tuberculosis in swine and in differentiating infections due to different serotypes of M avium.

Multiple skin testing in leprosy

Groups of patients with lepromatous and tuberculoid leprosy and hospital staff from six leprosaria in East Africa and 'non-contact' groups of villagers or staff from general hospitals have been skin tested with 10 reagents. These were prepared by ultrasonic disintegration from M. tuberculosis, M. duvalii, M. chelonei and 7 other species identified in the Ugandan environment. Comparisons were made of the percentages of positive reactors in each study group for each reagent. The 'specific' defect of lepromatous patients was found to apply to a variable extent to six of the species tested, but not to M. tuberculosis, M. avium or M. 'A'. The defect applied most noticeably to M. nonchromogenicum and M. vaccae, suggesting that they are more closely related to M. leprae than are the other species tested. The reagent Chelonin produced unexpected and anomalous results in the lepromatous group. It is suggested that this was due to an unusually slow clearing of Arthus' reaction.

Lesions and tuberculin sensitivity in calves inoculated with group III mycobacterial isolates from swine, pen soil, and cattle feed

FIFTEEN calves, 7 to 11 months of age, were inoculated intradermally with group III mycobacteria ---6 isolates from swine, 1 isolate from cattle feed, and 2 isolates from soil of swine farrowing pens. Calves were tuberculin tested at 50 days and killed approximately 60 days after inoculation. Only 1 of the cultures, that of porcine origin (93c-0), produced any lesions. There were a caseo-calcareous granuloma 3mm in diameter in the regional lymph node (left prescapular) and a granuloma at the skin inoculation site. None of the 5 calves inoculated with soil- or feed-origin mycobacteria had any lesions. Three of the calves inoculated with porcine origin group III mycobacteria had suspicious or positive caudal fold reactions. Two of these had granulomas at the skin-inoculation sites and one had no lesions. The calf having lymph node and skin-inoculation site granulomas was negative. The 5 calves inoculated with feed- or soil-origin mycobacteria had negative caudal fold tuberculin tests.

The indirect fluorescent antibody test for the detection of circulating antibodies in bovine tuberculosis

Indirect fluorescent antibody (IFA) tests were carried out on a total of 545 individual serums from beef cattle just before tuberculin testing, using specific FITC-anti-bovine IgG and IgM conjugates. Phenol-killed M. tuberculosis (H37Rv strain) or field strains of M. bovis and M. avium were used as antigenic substrates. All cattle were examined at abattoirs for the presence of tuberculous lesions. A statistically significant difference (p less than 0.001) was found between the number of cattle with serums containing IgM and those with IgG antibody to M. bovis. The majority of cross-reactions that occurred with M. avium was due to IgM antibody. The IFA test using M. bovis and both antiglobulin conjugates detected 77% of cattle with visible lesions of tuberculosis, while the single intradermal caudal fold tuberculin test detected 83%. The IFA test detected 25 of 31 cattle with lesions that failed to react in the tuberculin test. The tuberculin test gave apparently false positive reactions in 6.2% and the IFA test gave false positive reactions in 21.2% of all cattle. The IFA test is of potential use as a further aid in the detection of tuberculous cattle that fail to react to tuberculin. It offers no advantage over the tuberculin test for the detection of all forms of the disease because it fails to detect a significant proportion of tuberculous cattle and produces an unacceptably high number of false positive results.

Comparison of the specificity of human and bovine tuberculin PPF for testing cattle. 3. National trial in Great Britain

A field trial on a country-wide basis was undertaken to compare the specificity for bovine tuberculosis of single and comparative tuberculin tests in cattle using either Weybridge human or Weybridge bovine PPD. The tests were made on 10,305 cattle in 179 herds distributed throughout all regions of England, Scotland and Wales. Results showed that a comparative tuberculin test using avian PPD with either human or bovine PPD had a much higher efficiency than a single injection of mammalian tuberculin in the neck of cattle, and confirmed that a comparative test is still essential in the British environment. Weybridge bovine PPD gave significantly better discrimination between tuberculous and non-tuberculous cattle than Weybridge human PPD when used together with avian PPD in a comparative tuberculin test. The diameter of induration gave an absolute measure of the extent of oedema, if present, and induration diameter used in conjunction with skin thickening increased the sensitivity and specificity of the test. Rules of interpretation were developed and are presented for an intradermal comparative tuberculin test in cattle using Weybridge avian and bovine PPDs.

Comparison of the specificity of human and bovine tuberculin PPD for testing cattle. 2. South-eastern England

A tuberculin testing trial was carried out in eight counties of south-eastern England to compare the specificity for bovine tuberculosis of Weybridge human PPD with that of Rotterdam bovine PPD. The matching of these two tuberculins for potency in naturally infected cattle had already been established, the bovine PPD being approximately one-and-a-half times more potent than the human PPD per unit of weight. In 1110 cattle in 25 herds with histories of long-standing freedom from tuberculosis and in which non-specific tuberculin sensitivity was present, cross reactions were less to the bovine PPD than to the human PPD, showing that in the environment of this trial the bovine PPD was more specific than the human PPD. Induration diameter was a satisfactory alternative to skin thickening as a measure of tuberculin reactions in cattle under field conditions. Due to the steep slope of the dose-response curves of the avian PPD in the different groups of non-tuberculous cattle, the discriminating power of the comparative test, using avian and mammalian tuberculins, was less at lower doses of tuberculin. Concentrations of 1-0 mg per ml of bovine PPD and 0-5 mg per ml of avian PPD are recommended for use in a comparative tuberculin test.

Development of specific in vitro lymphocyte responses in cattle infected with Mycobacterium bovis and with Mycobacterium avium

Two calves infected with Mycobacterium avium and another 2 with Mycobacterium bovis were studied for development and specificity of lymphocyte activation responses and skin reactivity to purified protein derivatives (PPD). Lymphocytes cultured in vitro from infected calves manifested significant uptake of tritiated thymidine in response to the PPD prepared from the homologous organisms, whereas heterologous PPD produced little or no stimulation. The time of appearance of specifically sensitized lymphocytes was studied, as was the specificity of skin reactivity.