Evidence for interferon (IFN) induction in mice and humans by a fraction of bacterial extracts (SLO4) in vitro and after oral administration in vivo

Immunologic effects of yogurt

Many investigators have studied the therapeutic and preventive effects of yogurt and lactic acid bacteria, which are commonly used in yogurt production, on diseases such as cancer, infection, gastrointestinal disorders, and asthma. Because the immune system is an important contributor to all of these diseases, an immunostimulatory effect of yogurt has been proposed and investigated by using mainly animal models and, occasionally, human subjects. Although the results of these studies, in general, support the notion that yogurt has immunostimulatory effects, problems with study design, lack of appropriate controls, inappropriate route of administration, sole use of in vitro indicators of the immune response, and short duration of most of the studies limit the interpretation of the results and the conclusions drawn from them. Nevertheless, these studies in toto provide a strong rationale for the hypothesis that increased yogurt consumption, particularly in immunocompromised populations such as the elderly, may enhance the immune response, which would in turn increase resistance to immune-related diseases. This hypothesis, however, needs to be substantiated by well-designed randomized, double-blind, placebo-controlled human studies of an adequate duration in which several in vivo and in vitro indexes of peripheral and gut-associated immune response are tested.

Clinical value of measuring the interferon-induced enzyme 2'-5'-oligoadenylate synthetase in children

2'-5'-oligoadenylate synthetase, an interferon-induced enzyme and a sensitive indicator of the presence of interferon, was measured in peripheral blood mononuclear cells in children with inflammatory disorders of known and unknown origin in order to assess the value of such a test in patient management. Differences in median 2'-5'-oligoadenylate synthetase values in groups of children with viral or bacterial diseases or healthy children were observed. Considerable overlap of the 2'-5'-oligoadenylate synthetase range in the three groups was observed. All children with acute viral infections had increased levels early in their disease and a low value clearly argued against an acute viral infection. However, as more than one-third of children with bacterial diseases displayed elevated 2'-5'-oligoadenylate synthetase concentrations, distinction between a viral and bacterial cause of disease by measuring this enzyme was difficult. Estimation of 2'-5'-oligoadenylate synthetase concentrations in patients with inflammatory diseases of unknown origin, including juvenile rheumatoid arthritis, systemic lupus erythematosus, idiopathic uveitis and glomerulonephritis did not contribute to establishing a diagnosis or measuring disease activity.

Influence of SLO4 on the leucocyte migration inhibiting factor and on the DTH response

This phase I study demonstrates the immunostimulating properties of SLO4 administered by the oral route in the healthy volunteer. Responses to the test of DTH (delayed type hypersensitivity) were enhanced by SLO4 and the production of MIF (migration inhibiting factor) involved in this response was stimulated. These properties could be correlated with the previously demonstrated induction of interferon by SLO4.