Cellular immune responses to beta casein: elevated in but not specific for individuals with Type I diabetes mellitus.

Elevated cellular immune responses against the cows' milk protein beta casein have been reported in individuals with Type I diabetes mellitus, a finding supportive of the concept that cows' milk consumption may be causative for the disease. We analysed cellular immune reactivities against beta casein in newly-diagnosed Type I diabetic patients, their immediate autoantibody negative relatives, and unrelated healthy individuals in order to further elucidate the role of anti-beta casein immunity in the pathogenesis of Type I diabetes mellitus. Peripheral blood mononuclear cells were stimulated in vitro with various concentrations of three different beta casein preparations, control antigens (tetanus toxoid, mumps extract) and a mitogen (phytohemagglutinin). The frequency and/or mean simulation index of cellular proliferation against two of the beta casein preparations at high antigen concentrations (i.e. 10 or 50 microg/ml) were significantly higher in newly-diagnosed Type I diabetic subjects compared with autoantibody negative healthy control subjects. However, reactivities against beta casein in the Type I diabetic probands and their autoantibody negative relatives, individuals with a very low-rate of disease development, were almost identical. Cellular immune reactivities to other antigens were similar between the subject groups. In addition to indicating the need for appropriately matched subject populations (e.g. human leukocyte antigen (HLA) matched relatives) when analysing cellular immune responses, these findings support our previous contention that individuals genetically prone to autoimmunity may be deficient in forming tolerance to dietary antigens. However, the significance of anti-beta casein immunity as a specific causative factor in the pathogenesis of Type I diabetes mellitus remains unclear.

The relationship between humoral and cellular immunity to IA-2 in IDDM.

Autoantibodies to the neuroendocrine protein insulinoma-associated protein 2 (IA-2), a member of the tyrosine phosphatase family, have been observed in individuals with or at increased risk for IDDM. Because this disease is thought to result from a T-cell-mediated autoimmune destruction of the insulin-producing pancreatic beta-cells, we analyzed humoral and cellular immune reactivity to this autoantigen to further define its role in the pathogenesis of IDDM. Peripheral blood mononuclear cells (PBMC) from individuals with newly diagnosed IDDM or at varying levels of risk for the disease were stimulated in vitro with the entire 42-kDa internal domain of IA-2 (amino acids 603-979), a series of control antigens (glutathionine-S-transferase, tetanus toxoid, Candida albicans, mumps, bovine serum albumin), and a mitogen (phytohemagglutinin). The frequency and mean stimulation index of PBMC proliferation against IA-2 was significantly higher in newly diagnosed IDDM subjects (14 of 33 [42%]; 3.8+/-4.5 at 10 microg/ml) and autoantibody-positive relatives at increased risk for IDDM (6 of 9 [66%]; 3.9+/-3.2) compared with autoantibody-negative relatives (1 of 15 [7%]; 1.8+/-1.0) or healthy control subjects (1 of 12 [8%]; 1.5+/-1.0). The frequencies of cellular immune reactivities to all other antigens were remarkably similar between each subject group. Sera from 58% of the newly diagnosed IDDM patients tested were IA-2 autoantibody positive. Despite investigations suggesting an inverse association between humoral and cellular immune reactivities against islet-cell-associated autoantigens, no such relationship was observed (rs=0.18, P=0.39) with respect to IA-2. These studies support the autoantigenic nature of IA-2 in IDDM and suggest the inclusion of cellular immune responses as an adjunct marker for the disease.

Issues in the care of infants and toddlers with insulin-dependent diabetes mellitus.

Infants and children in the preschool age group who have insulin-dependent diabetes mellitus present a unique set of problems to the health care provider and to their families. These management issues include difficulty in achieving maximal metabolic control; the limited ability of the child to communicate feelings and needs; a significant financial burden to many young families; and the increased family stress and altered psychodynamics seen in families with very young children with chronic illnesses. The lability of diet, exercise, emotions, and overall life-style seen in this age group exacerbates each of these problems markedly. This paper addresses the challenges that these children present; discusses the issues and controversies; and describes how the Diabetes Clinic at Michigan State University uses a combination of methodologies and disciplines to deal with these problem areas.

Biotransformation of dehydroabietic acid with resting cell suspensions and calcium alginate-immobilized cells of Mortierella isabellina.

Mortierella isabellina ATCC 38063 is a zygomycete capable of hydroxylating fish-toxic resin acids which occur in certain pulp mill effluents to nontoxic metabolites. Addition of dehydroabietic acid (1) (80 mg/liter) to a freshly inoculated culture of M. isabellina in dextrose-yeast extract broth resulted in precursor disappearance in 28 to 30 h. During growth phase, hydroxylation occurred at C-2, whereas hydroxylation at C-15 and C-16 commenced with onset of stationary phase. Alternatively, 1 added to stationary-phase culture (40 mg/liter) disappeared within 2 h and hydroxylation occurred concurrently at C-2, C-15, and C-16. Enzymatic activity of stationary-phase culture was totally cell associated and was present despite the absence of 1 during the preparatory growth phase. Resuspension of mature fungi as free mycelia or immobilized in calcium alginate beads did not diminish the effectiveness of the biotransformation, although two new metabolites, 15-hydroxy-8,9,11,12-tetradehydro-7,8-dihydroabietic acid (5) and 16-hydroxy-8,9,11,12-tetradehydro-7,8-dihydroabietic acid (7) were formed. Immobilized mycelia retained hydroxylase activity for greater than 110 days whether or not they were challenged with fresh 1 on a regular basis. In this respect they are more long-lived than resuspended free mycelia are.