Prolactin-immunoglobulin G complexes from human serum act as costimulatory ligands causing proliferation of malignant B lymphocytes.

Upon activation, B lymphocytes can change the isotype of the antibody they express by immunoglobulin (Ig) isotype switch recombination. In previous studies on the regulation of human IgG expression, we demonstrated that interleukin 10 (IL-10) could stimulate IgG1 and IgG3 secretion by human CD40-activated naive (sIgD+) tonsillar B cells. To assess whether IL-10 actually promotes the DNA recombination underlying switching to these isotypes, we examined the effect of IL-10 on the generation of reciprocal products that form DNA circles as by-products of switch recombination. The content of reciprocal products characteristic of mu-gamma recombination was elevated after culture of CD40-activated tonsillar sIgD+ B cells with either IL-4 or IL-10, although high levels of IgG secretion were observed only with IL-10. Unlike IL-4, IL-10 did not induce reciprocal products of mu-epsilon and gamma-epsilon switch recombination. These results demonstrate that IL-10 promotes both switching to gamma and IgG secretion.

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Binding of enzyme--IgG complexes in human serum to Protein-A Sepharose CL-4B.

Clinical Chemistry ◽

10.1093/clinchem/26.2.0297 ◽

1980 ◽

Vol 26 (2) ◽

pp. 297-300

Author(s):

K Bauer ◽

P M Bayer ◽

E Deutsch ◽

F Gabl

Keyword(s):

Alkaline Phosphatase ◽

Creatine Kinase ◽

Human Serum ◽

Immunoglobulin G ◽

Protein A ◽

The Other ◽

Routine Method ◽

Simple Method ◽

Human Serum Protein ◽

Enzyme Complexes

Abstract We describe a simple method for detecting enzyme--immunoglobulin G (IgG) complexes in human serum. Protein-A Sepharose CL-4B binds IgG and therefore also the enzyme--IgG complexes, which can then be separated easily from the serum by centrifugation. We demonstrate this separation in two patients, one with a complex of IgG and creatine kinase (EC 2.7.3.2) BB isoenzyme, the other with an IgG--alkaline phosphatase (EC 3.1.3.1) complex. Both patients had unexplainably high activities of the respective enzymes in their serum. The method we propose should be a useful, simple, routine method of detection in cases where IgG--enzyme complexes are suspected.

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Autoantibodies to thyroxin and triiodothyronine in the immunoglobulin G fraction of serum.

Clinical Chemistry ◽

10.1093/clinchem/34.12.2561 ◽

1988 ◽

Vol 34 (12) ◽

pp. 2561-2562 ◽

Cited By ~ 8

Author(s):

L Li Calzi ◽

S Benvenga ◽

S Battiato ◽

F Santini ◽

F Trimarchi

Keyword(s):

Thyroid Hormone ◽

Thyroid Hormones ◽

Human Serum ◽

Immunoglobulin G ◽

Subacute Thyroiditis ◽

Total Serum ◽

Graves Disease ◽

Carrier Proteins ◽

Weak Binding ◽

Idiopathic Myxedema

Abstract Thyroid hormone antibodies (THAbs)--i.e., antibodies to thyroxin (T4) and triiodothyronine (T3)--are detected rarely in human serum, where they are searched for, possibly because of a quantitatively minimal interaction between thyroid hormones (the haptens) and serum IgGs (the antibodies). The weak binding could result from these facts: (a) there are already six physiological carrier proteins for thyroid hormones; (b) THAbs usually account for a very small fraction of the total serum IgGs; (c) THAbs may have--as reported in the literature--a relatively low affinity. To ascertain whether THAbs could pass undetected in serum, we measured antibodies to T3 and T4 in both the serum and the corresponding IgG fraction of six normal persons and 45 patients with various thyroid diseases (Graves' disease, idiopathic myxedema, Hashimoto's thyroiditis, subacute thyroiditis, tumors), using radioimmunoprecipitation. The prevalence of antibodies to T4 was 0/51 in both the sera and the IgG fractions; the prevalence of antibodies to T3 was 1/51 in both materials. Because all of the sera that tested THAb negative were confirmed to be so in the THAb assay of the IgG fraction, we conclude that the prevalence of serum THAbs is not underestimated and that autoimmunization against thyroid hormones is really a rare phenomenon.

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Complexes of lactate dehydrogenase and immunoglobulin G in human serum

Clinica Chimica Acta ◽

10.1016/0009-8981(73)90308-2 ◽

1973 ◽

Vol 47 (2) ◽

pp. 139-147 ◽

Cited By ~ 17

Author(s):

Jeike Biewenga

Keyword(s):

Lactate Dehydrogenase ◽

Human Serum ◽

Immunoglobulin G

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A new approach to the depletion of albumin and immunoglobulin G from human serum

Applied Biochemistry and Microbiology ◽

10.1134/s0003683815030047 ◽

2015 ◽

Vol 51 (3) ◽

pp. 367-373 ◽

Cited By ~ 1

Author(s):

E. A. Bormotova ◽

B. L. Mil’man ◽

T. V. Gupalova

Keyword(s):

Human Serum ◽

Immunoglobulin G ◽

New Approach

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The nature of the immunoglobulin G on the surface of B lymphocytes in chronic lymphocytic leukemia.

Journal of Experimental Medicine ◽

10.1084/jem.154.6.1965 ◽

1981 ◽

Vol 154 (6) ◽

pp. 1965-1969 ◽

Cited By ~ 23

Author(s):

F K Stevenson ◽

T J Hamblin ◽

G T Stevenson

Keyword(s):

Chronic Lymphocytic Leukemia ◽

Cell Surface ◽

B Lymphocytes ◽

Immunoglobulin G ◽

Lymphocytic Leukemia ◽

Absorption Studies ◽

Ig G

The nature of the immunoglobulin (Ig) G found associated with the neoplastic B lymphocytes in chronic lymphocytic leukemia that also express Igm and IgD had been investigated by absorption studies using anti-idiotypic antibodies raised against cell surface IgM from five patients. In all five cases, although cellular IgM and IgD behaved as idiotypic, the IgG did not. Thus the IgG frequently found associated with lymphocytes at this stage of differentiation is likely, at least in many cases, to be of extrinsic origin.

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