Selenium (Se) is an essential nutritional factor that affects the development and expression of cell-mediated immune responses directed toward malignant cells. These studies have shown that dietary (2 ppm for 8 wk) or in in vitro (1 x 10(-7)M) supplementation with Se (as sodium selenite) results in a significant enhancement of the proliferative responses of spleen lymphocytes from C57Bl/6J mice in response to stimulation with mitogen or antigen. Se deficiency (0.02 ppm for 8 wk) had the opposite effect. The alterations in the ability of the cells to proliferate, which occurred in the absence of changes in the endogenous levels of interleukin-2 (Il2) or interleukin 1, were apparently related to the ability of Se to alter the kinetics of expression of high-affinity Il2 receptors on the surface of activated lymphocytes. This resulted in an enhanced or delayed clonal expansion of the cells, and in an increased or decreased frequency of cytotoxic cells within a given cell population. The changes in tumor cytotoxicity were paralleled by changes in the amounts of lymphotoxin produced by the activated cells. Dietary Se modulations had a comparable effect on macrophage-mediated tumor cytodestruction. The results also suggested that Se exerts its effect 8-24 h after stimulation, and that it most likely affects processes in the cytoplasmic and/or nuclear compartments of activated lymphocytes.

Animals↗

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Supplementation with selenium and human immune cell functions. I. Effect on lymphocyte proliferation and interleukin 2 receptor expression.

Selenium (Se) is an essential nutritional factor that was shown by us to alter the expression of the high affinity interleukin 2 receptor (Il2-R) and its subunits, cell proliferation, and clonal expansion of cytotoxic T-lymphocytes in mice. This study shows that dietary supplementation of Se-replete humans with 200 micrograms/d of sodium selenite for 8 wk, or in vitro supplementation with 1 x 10(-7) M Se (as sodium selenite), result in a significant augmentation of the ability of peripheral blood lymphocytes to respond to stimulation with 1 microgram/mL of phytohemagglutinin or alloantigen (mixed lymphocyte reaction) and to express high affinity Il2-R on their surface. There was a clear correlation between supplementation with Se and enhanced 3H-thymidine incorporation into nuclear DNA, preceded by enhanced expression of high affinity Il2-R. Supplementation with Se can apparently modulate T-lymphocyte mediated immune responses in humans that depend on signals generated by the interaction of interleukin 2 with Il2-R.

Adult↗

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Supplementation with selenium and human immune cell functions. II. Effect on cytotoxic lymphocytes and natural killer cells.

This study examined the effect of dietary (200 micrograms/d for 8 wk) supplementation with selenium (as sodium selenite) on the ability of human peripheral blood lymphocytes to respond to stimulation with alloantigen, develop into cytotoxic lymphocytes, and to destroy tumor cells, and on the activity of natural killer cells. The participants in the study were randomized for age, sex, weight, height, and nutritional habits and given selenite or placebo tablets; all participants had a selenium replete status as indicated by their plasma Se levels prior to supplementation. The data indicated that the supplementation regimen resulted in 118% increase in cytotoxic lymphocyte-mediated tumor cytotoxicity and 82.3% increase in natural killer cell activity as compared to baseline values. This apparently was related to the ability of the nutrient to enhance the expression of receptors for the growth regulatory lymphokine interleukin-2, and consequently, the rate of cell proliferation and differentiation into cytotoxic cells. The supplementation regimen did not produce significant changes in the plasma Se levels of the participants. The results indicated that the immunoenhancing effects of selenium in humans require supplementation above the replete levels produced by normal dietary intake.

Adult↗

PubMedDate not supplied

Differentiation by electrophoresis and enzymoserology of proteinases, produced by strains of Staphylococcus epidermidis biotypes 1 and 4.

Electrophoretic and serologic characterization of extracellular proteinases from 111 isolates (80 biotype 1 and 31 biotype 4) of Staphylococcus epidermidis (coagulase negative) of human origin were conducted. Seventy-seven (60 of biotype 1, 17 of biotype 4) of the 111 proteinase-positive isolated of S. epidermidis were classified by serological differentiation of their proteolytic enzymes with known specific antisera. Thirty-two (18 of biotype 1, 14 of biotype 4 (isolates of S. epidermidis produced proteolytic enzymes that did not react with any of the known group antisera and were classified as NR (non-reacting). No classification of the enzymes of two other isolates was possible. The NR proteinase enzymes from the 32 cultures that could not be classified by serological differentiation with the known specific antisera fitted into one of three electrophoretic mobility patterns: NR1, NR2 or NR3. Seventy-eight isolates of S. epidermidis biotype 1 were placed into four proteinase sero-groups; 49 in F, 11 in B, 11 in NR2, and 7 in NR3. Thirty-one isolates of S. epidermidis biotype 4 were placed into one of two groups: 17 in C and 14 in NR. All enzymes tested migrated towards the anode at pH 8.6, and the order of electrophoretic mobility was NR3 greater than F greater than NR2 greater than NR1 greater than B greater than C.

Caseins↗

PubMedDate not supplied

Morphological abnormalities of fungi induced by volatile microbial metabolites.

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Aspergillus↗

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Differentiation of strains of Staphylococcus epidermidis biotypes 1 and 4 by aminopeptidase profiles.

Seven different strains of Staphylococcus epidermidis and one strain of S. aureus were catagorized by their aminopeptidase activity. Eight different profiles were obtained: five profiles for S. epidermidis biotype 4 (each representing a different known serotype), two profiles for S. epidermidis biotype 1 (one for each strain used) and one for the strain of S. aureus used. Despite some similarities, distinct patterns of the hydrolysis of 22 different amino acid-beta-naphthylamides were evident for each individual strain. The evaluation of aminopeptidase profiles provides another means for distinguishing between strains of the same species and can, therefore, be used advantageously and in combination with serotyping as an epidemiological tool.

2-Naphthylamine↗

PubMedDate not supplied

Staphylococcus epidermidis biotype 4: epidemiological conclusions from five different typing methods.

There is presently no accepted method for marking individual strains of Staphylococcus epidermidis. Consequently, five parameters for distinguishing such strains were examined and compared for their epidemiological efficacy: biotyping, serotyping, proteinase grouping, aminopeptidase profiles and antibiograms. Both biotyping and proteinase grouping were of limited use in identifying a particular strain, although they were helpful in initially categorizing such strains. Antibiograms were least useful because of similarities in susceptibility patterns among isolates. Serotyping and amino-peptidase profiles provided the best means of identifying an individual strain for epidemiological use. The applicability of these typing methods was demonstrated during a one year epidemiological study at a chronic disease hospital.

Aminopeptidases↗