In vitro stimulation of lymphocytes in leprosy patients, healthy contacts of leprosy patients, and subjects not exposed to leprosy. Comparison of an antigen fraction prepared from Mycobacterium leprae and tuberculin-purified protein derivative.

In vitro lymphocyte stimulation was performed on peripheral blood lymphocytes from 48 leprosy patients, 15 healthy contacts of leprosy patients, and 16 normal controls who lived in a leprosy-free area and who had not been exposed to leprosy. Tuberculin PPD and an antigen fraction. MLW 1, prepared from M. leprae, were used as stimulants. The MLW 1 preparation contained one antibody-precipitable component when tested in crossed immunoelectrophoresis against a polyvalent anti-M. leprae immunoglobulin preparation, namely the ML 7 antigen. MLW 1 induced strong lymphocyte responses in patients with tuberculoid leprosy and healthy contacts of leprosy patients, but only a weak or no responses in lepromatous leprosy patients and non-exposed controls. A marked depression of the response to tuberculin PPD was observed in lepromatous leprosy patients. The specificity of the MLW 1 antigen is discussed, and a new estimator of specific lymphocyte stimulation, the delta cpm', is introduced.

Cross-reactions between serum proteins and water soluble liver tissue antigens of the nine-banded armadillo (Dasypus novemcinctus Linn.) and man.

Cross-reactions between serum proteins and water soluble liver antigens of the nine-banded armadillo (Dasypus novemcinctus Linn.) and man were studied by crossed immunoelectrophoresis (CIE). Armadillo serum tested with rabbit antiserum against human serum proteins gave twelve components in CIE. Nine of these cross-reacting proteins were identified and showed partial identity with the corresponding human proteins. The electrophoretic mobility of alpha 2-macroglobulin and Gc-globulin differed in the two species. An ultrasonicate of normal armadillo liver gave twenty-eight anodic and eight cathodic components in CIE. By absorption experiments with armadillo serum, twenty of the former and seven of the latter were shown to be liver tissue components. A combination of CIE and crossed-line immunoelectrophoresis (CLIE) revealed the presence of twelve anodic and six cathodic liver tissue components cross-reacting with man. A cathodic armadillo liver antigen called (CALA-17) showed partial identity with that of man both in tandem and fused rocket immunoelectrophoresis. The implications of the findings are discussed in relation to the use of armadillo-grown M. leprae for skin testing and other purposes in man.

False spurs in quantitative immunoelectrophoresis.

Antigens which show reactions of identity in double-diffusion tests in gel may cause spur formation in crossed immunoelectrophoretic techniques. To differentiate these misleading spurs from spurs of double-diffusion tests which show the true immunochemical relationship between antigens, we have denoted the former type "false spurs". False spurs are often formed in tandemcrossed immunoelectrophoresis and fused rocket immunoelectrophoresis when antigens with different electrophoretic mobility are compared. On the basis of model experiments, criteria are set up for accepting a spur as a true spur, and procedures are described for avoiding formation of false spurs in quantitative immunoelectrophoresis.

Subclinical infection in leprosy.

Lymphocyte transformation has been used to study the immune response to Mycobacterium leprae among contacts and non-contacts of leprosy patients. Of 26 subjects living in a leprosy endemic area for less than two months none responded to M. leprae; 24% of subjects who had lived in an endemic area for more than a year gave a positive response to M. leprae; more than 50% of individuals with occupational contact of leprosy for more than a year responded; and about 50% of contacts of tuberculoid and treated lepromatous patients responded to M. leprae, while only 22% (4/18) of contacts of lepromatous patients treated for less than six months responded.It seems that leprosy is more highly infectious than is indicated by the prevalence of the disease and that a subclinical infection commonly follows exposure to M. leprae. The relatively low response found in contacts of active lepromatous patients suggests that in these contacts "superexposure" to M. leprae can bring about a decrease in host resistance.