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Biomedical subjects

I Berggård

Publications and source records attributed to I Berggård.

At least 19 recordsLinked to original sources
PubMed1981

Isolation and characteristics of human urinary sialoglycoproteins.

Three sialoglycoproteins (S1, S2, and S3) have been isolated from normal human urine by ultrafiltration, zone electrophoresis, gel chromatography, and ion-exchange chromatography. The average yields per litre of urine were 0.39 mg (S1), 0.40 mg (S2), and 1.9 mg (S3). The isolated substances were homogeneous on ultracentrifugation both at neutral and acid pH with sedimentation coefficients of 3.6 S (S1), 2.4S (S2), and 0.93S (S3). Equilibrium ultracentrifugation gave molecular weights of 77900 (S1), 37000 (S2), and 5300 (S3). All three components were rich in carbohydrate (64 to 76%) and contained 28 to 35% of sialic acid. Alkaline borohydride degradation of component S3 yielded two sialylated oligosaccharides which were partially characterized. The origin of the isolated substances is unknown. The molecular size of S3 (Stokes' radius of 2.0 nm) is compatible with passage from the blood by glomerular filtration whereas the size of S1 (Stokes' radius of 6.5 nm) would suggest a renal origin.

Chemical Phenomena↗
PubMed1979

Occurrence of beta 2-microglobulin in mammalian lymphocytes and erythrocytes.

Cell-associated beta 2-microglobulin (beta 2m) has been studied by quantitative techniques in lymphocytes and erythrocytes of guinea pig, rabbit, rat and man. beta 2m was solubilized by sonication followed by treatment with acid, deoxycholate or thiocyanate, and then determined by radioimmunoassay. The average number of beta 2m molecules per lymphocyte, estimated after acidification, varied between 0.89 X 10(5) and 7.1 X 10(5). Rat erythrocytes contained 3.0 X 10(3) molecules per cell, whereas no beta 2m was detected in red blood cells from the three other species. A relatively large part of beta 2m in the mammalian lymphocytes and in rat erythrocytes was present on the cell surface according to a radioimmunoassay procedure using anti-beta 2m antisera that had been absorbed with the blood cells analyzed.

Animals↗
PubMed1979

Effects of anti-guinea-pig beta 2-microgloblin antibodies on lymphocyte transformation induced by specific antigens or mitogens.

The effects of a goat anti-guinea-pig beta 2-microglobulin antiserum (a beta 2m) on lymphocyte transformation, induced by specific antigens or mitogens, were studied. a beta 2m was found to exert inhibitory effects on antigen stimulation, with three different antigens (purified protein devivative, hen egg-white lysozyme, and ovalbumin), and on stimulation induced by the 'T-cell mitogens', concanavalin A and phytohaemagglutinin, and the 'mixed mitogen', pokeweed mitogen. Stimulation induced by the 'B-cell mitogens', dextran sulphate and bacterial lipopolysaccharide, did not seem to be inhibited to the same extent by a beta 2m. The inhibitory effects seemed specific, as they were not seen with a beta 2m that had been absorbed on a column with insolubilized purified guinea-pig beta 2m nor with normal goat serum. Time studies indicated that the inhibitions started already during the first day of culture.

Animals↗
PubMed1979

The activation of guinea pig T lymphocytes by anti-beta 2-microglobulin serum.

In order to study further the role of beta 2-m in the regulation of the immune response, we have examined the effects of a goat anti-guinea pig beta 2-m serum on a number of T lymphocyte functions in vitro. Anti-beta 2-m serum produced a marked inhibition of the response of peritoneal exudate T cells to antigen and mitogen stimulation. Surprisingly, a marked activation of lymph node T lymphocyte proliferation was observed in the absence of antigen or mitogen stimulation. This stimulatory effect of anti-beta 2-m serum was shown to be specific for beta 2-m and required the presence of macrophages. The T cell proliferative response induced by anti-beta 2-m could not be blocked by antisera to the antigens of the guinea pig MHC. These studies suggest that beta2-m may play some critical role in the immune response at the level of T cell activation.

Animals↗
PubMed1979

In search of alpha 1-microglobulin on the lymphocyte surface.

alpha 1-Microglobulin was found by immunofluorescence not to be associated with human lymphoid and nonlymphoid cell lines. No accumulation of alpha 1-microglobulin was detected in culture media of these cell lines. A weak membrane fluorescence with anti-alpha 1-microglobulin on peripheral lymphocytes could not be blocked by the purified protein. No release of alpha 1-microglobulin into the growth medium was seen by normal cultured leukocytes. Treatment of normal lymphocytes, erythrocytes, and various cell lines with solubilization techniques did not yield any alpha 1-microglobulin. alpha 1-Microglobulin and protein HC display immunologic and biochemical identity. However, anti-protein HC stained almost all of the tested cell lines and normal lymphocytes. Blocking experiments with the purified protein were not successful. Antibodies reacting with a minor impurity (50,000 d) in the alpha 1-microglobulin or protein HC preparations could be absorbed from anti-alpha 1-microglobulin with normal leukocytes and a lymphoid cell line.

Absorption↗
PubMed1978

Binding of aggregated human beta2-microglobulin to surface protein structure in group A, C, and G streptococci.

A novel mammalian-microbial "short circuit" has been demonstrated between aggregated human beta2-microglobulin and group A, C, and G streptococci. Bacteria belonging to nine gram-positive and three gram-negative species were tested for binding of radiolabeled beta2-microglobulin. All 10 individual strains of group A streptococci showed a high degree of reactivity with aggregated human beta2-microglobulin. Among 27 group C and 28 group G streptococci, 9 and 6 strains, respectively, were highly reactive, whereas the remaining strains showed a lower, but definite level of beta2-microglobulin binding. Of 11 group B streptococci, 4 were slightly positive. All strains among the other eight species were completely negative. Simultaneous testing of A, C, and G streptococci for immunoglobulin binding showed a lack of correlation between type II and III Fc reactivity and beta2-microglobulin binding. There was no inhibition of uptake of aggregated beta2-microglobulin to reactive strains when excess amounts of human immunoglobulin were added. The beta2-microglobulin-binding surface structure was found to be markedly sensitive to trypsin digestion. The relative trypsin resistance of the immunoglobulin-binding protein in the digestion experiments further demonstrated the dissociation between these two reactivities.

Bacterial Proteins↗
PubMed1977

Relationships between beta2-microglobulin and alloantigens coded for by the major histocompatibility complexes of the rabbit and the guinea pig.

Treatment of rabbit and guinea pig lymphocytes with Fab' fragments of anti-beta2-microglobulin completely inhibited the cytotoxic effects of alloantisera to RLA or GPLA antigens, respectively. Aggregation of beta2-microglobulin on the lymphocyte surface by successive incubations with goat anti-beta2-microglobulin on the lymphocyte surface by successive incubations with goat anti-beta2-microglobulin and F(ab')2 fragments of rabbit anti-goat IgG also made rabbit lymphocytes resistant to lysis by anti-RLA, and guinea pig lymphocytes resistant to lysis by anti-RLA, and guinea pig lymphocytes resistant to lysis by anti-GPLA. The two kinds of pretreatment of guinea pig lymphocytes did not affect the cytotoxicity of antisera directed against guinea pig Ia antigens. These results in conjunction with previous findings in the mouse and in man suggest that beta2-microglobulin on the lymphocyte surface in mammals is generally associated with major serologically defined histocompatibility antigens but not with I-region-associated antigens.

Animals↗