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B Akerström

Publications and source records attributed to B Akerström.

At least 55 records · Page 3Linked to original sources
PubMed1992

Protein L from Peptostreptococcus magnus binds to the kappa light chain variable domain.

Protein L is an immunoglobulin light chain-binding protein expressed by some strains of the anaerobic bacterial species Peptostreptococcus magnus. The major variable region subgroups of human kappa and lambda light chains were tested for protein L binding; V kappa I, V kappa III, and V kappa IV bound protein L, whereas no binding occurred with proteins of the V kappa II subgroup or with any lambda light chain subgroups. Studies of the protein L binding capacity of naturally occurring VL fragments, and VL- and CL-related trypsin- and pepsin-derived peptides prepared from a kappa I light chain, localized the site of interaction to the VL domain. The affinity constant for the binding to an isolated V kappa I fragment was comparable to that for the native protein (Ka 0.9 x 10(9) M-1 and Ka 1.5 x 10(9) M-1, respectively). No binding occurred with CL-related fragments. Extensive reduction and alkylation of the V kappa fragment or the native kappa chain resulted in complete loss of protein L binding. Although it is possible, from comparative amino acid sequence data, to identify certain VL-framework region residues that account for the selective binding of protein L by kappa I, kappa III, and kappa IV proteins, our studies indicate that this interaction is essentially dependent upon the tertiary structural integrity of the kappa chain VL domain.

Amino Acid Sequence↗
PubMed1991

Characterization of monoclonal anti-alpha 1-microglobulin antibodies: binding strength, binding sites, and inhibition of lymphocyte stimulation.

Eleven monoclonal antibodies (MoAb) directed against the immunoregulatory plasma glycoprotein alpha 1-microglobulin were characterized. The MoAb were produced in mice immunized with a mixture of alpha 1-microglobulin homologues from man, guinea pig, rat and rabbit. Using radioimmunoassay, western blotting, affinity chromatography, and Scatchard analysis, the affinities and binding sites of the MoAb were analysed. All antibodies were more or less cross-reactive, but most showed a major specificity for one or two of the alpha 1-microglobulin homologues. None of the antibodies was directed against the carbohydrate moiety of alpha 1-microglobulin. Six of the MoAb had high affinity for the antigen and four of these were directed towards the same part of the molecule though differing in their species specificity. Five showed lower affinity for the antigen and were mainly directed towards epitopes on other parts of the molecule. Only some of the antibodies could block the proliferation of lymphocytes induced by human alpha 1-microglobulin. The blocking efficiency of the different antibodies was similar when tested on the stimulation of human or mouse lymphocytes, suggesting that the same part of the alpha 1-microglobulin molecule is responsible in both species. The magnitude of blocking by the different MoAb was not related to their affinities, emphasizing the importance of where on the alpha 1-microglobulin molecule, rather than how strongly, they bind. The binding of the strongest blocking antibody was shown to be directed to a C-terminal peptide of rat alpha 1-microglobulin, indicating that this part of alpha 1-microglobulin is important for the mitogenic effects. Thus the panel of anti-alpha 1-microglobulin MoAb should be a valuable tool for structural and functional studies of alpha 1-microglobulin.

Alpha-Globulins↗
PubMed1990

Antibody response in immunized rabbits measured with bacterial immunoglobulin-binding proteins.

Protein G, an immunoglobulin (Ig)-binding protein isolated from group C or G streptococci, binds to the Fc portion of IgG. Protein L, from the anaerobic bacterium Peptostreptococcus magnus, specifically binds light chains of Ig. In this study, protein G and L were used to measure the production of antibodies in immunized rabbits. Two rabbits were immunized with a mixture of human urinary proteins from a patient with tubular proteinuria, and blood samples were collected regularly from the animals for 6 weeks after the immunization. The antibody levels of the blood samples against six of the proteins in the antigen mixture were then measured by ELISA. Microtiter plates were coated with each of the antigens, incubated with the rabbit serum samples, and the specific antibodies of the IgG class measured by incubation with biotinylated protein G, and antibodies of all Ig classes with biotinylated protein L. Alternatively, Western blotting was employed, where the antibodies which bound to each antigen after separation by SDS-PAGE and transfer to nitrocellulose membranes, were detected by protein G or L. The results showed that antibody production against five of the antigens, albumin, alpha 1 gamma-acid glycoprotein, alpha 1 gamma-microglobulin, Ig light chains, and retinol-binding protein, showed a similar pattern, although the magnitude of the initial IgM response differed somewhat. After 6 weeks, the levels of the protein G-binding antibodies had reached a plateau, while those of protein L-binding antibodies were still increasing. The response to the sixth antigen, beta 2 microglobulin, was considerably different. A dramatic increase of anti-beta 2 gamma-microglobulin antibodies was seen during the 4th week after immunization when protein L was used.

Animals↗
PubMed1990

Isolation of rat serum alpha 1-microglobulin. Identification of a complex with alpha 1-inhibitor-3, a rat alpha 2-macroglobulin homologue.

Alpha 1-Microglobulin (alpha 1-m), or protein HC, a low molecular weight plasma protein with immunoregulatory properties, was isolated from rat serum by affinity chromatography using Sepharose-coupled monoclonal anti-alpha 1-m antibodies. High molecular weight forms of alpha 1-m were then separated from the low molecular weight alpha 1-m by gel chromatography of the eluted proteins. The apparent Mr (28,000), the charge heterogeneity, the N-linked carbohydrate, and yellow-brown chromophore suggest that the low molecular weight alpha 1-m is the serum counterpart to urinary alpha 1-m, which was purified previously. A high molecular weight complex of alpha 1-m was also isolated by the gel chromatography. It was homogeneous as judged by nondenaturing polyacrylamide gel electrophoresis. The molecule was bound by antibodies against human alpha 2-macroglobulin, and experiments with antisera against the three alpha-macroglobulin variants in rat serum, alpha 1-macroglobulin, alpha 2-macroglobulin, and alpha 1-inhibitor-3 (alpha 1I3) suggested that alpha 1I3 was the complex-partner of alpha 1-m. An antiserum raised against high molecular weight alpha 1-m was then used to isolate the complex-partner of alpha 1-m from rat serum with affinity chromatography, and this molecule was positively identified as alpha 1I3 by its physicochemical properties. Gel chromatography of the alpha 1I3.alpha 1-m complex suggested a molecule with an Mr of 266,000. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, however, it migrated as three major molecular species with apparent molecular weights of 224,000, 205,000, and 194,000 and several minor species of both higher and lower molecular weights, suggesting a complex subunit structure. alpha 1-m and alpha 1I3 could be detected in all three major species by Western blotting, and NH2-terminal amino acid sequencing suggested a molar ratio of 1:1 of alpha 1-m and alpha 1I3 in all three species. alpha 1I3.alpha 1-m was colorless, did not show light absorbance beyond 300 nm which is typical of low molecular weight alpha 1-m and was electrophoretically homogeneous, suggesting that it lacks the chromophore. Finally, the serum concentrations of the alpha 1I3.alpha 1-m complex and free alpha 1-m were determined as 0.16 and 0.010 g/liter, respectively. Thus, alpha 1I3.alpha 1-m constitutes 1-3% of the total alpha 1I3 in rat serum (w/w) and approximately 60% of the total alpha 1-m.

Alpha-Globulins↗
PubMed1990

Monoclonal antibodies to the pituitary growth-hormone receptor by the anti-idiotypic approach. Production and initial characterization.

We obtained 10/192 and 3/384 antibody-secreting hybrids after immunization of Balb/c mice with either human growth hormone or affinity-purified rabbit anti-(human growth hormone) respectively. Radiolabelled rabbit anti-(human growth hormone) antibodies, but not human growth hormone, were specifically bound by supernatants from the 13 hybrids. The binding was completely inhibited by human-growth-hormone serum binding protein. However, anti-(human growth hormone antibodies) were detected in the sera of all the mice immunized with human growth hormone. In an independent fusion, which was carried out after immunization with fewer doses of human growth hormone, anti-(human growth hormone) antibodies were also obtained. Five hybrids, where the starting antigen was human growth hormone, were selected for ascites production, and the corresponding monoclonal antibodies were partially purified and characterized with respect to their immunoglobulin isotype and their interaction with human-growth-hormone receptors. These antibodies were found to enhance the binding of radioiodinated human growth hormone to human-growth-hormone serum binding protein from human and rabbit plasma by 40%. Scatchard analysis of the effect of one of the monoclonal antibodies showed that this enhancement was due to an increased number of binding sites. All of the partially purified antibodies but one (F12) inhibited the binding of human growth hormone to rat but not rabbit, liver microsomes to various extents, as well as to H-4-II-E rat hepatoma cells. Monoclonal antibody F12 enhanced the binding of radiolabelled human growth hormone to rat liver microsomes and H-4-II-E hepatoma cells. This enhancement was found to be due to an increase in the number of binding sites.

Animals↗
PubMed1990

Characterization of an IgA receptor from group B streptococci: specificity for serum IgA.

Some strains of group B streptococci express a cell surface protein which binds IgA. This report describes some properties of such an IgA receptor and compares it with a previously described IgA receptor from group A streptococci. The group B receptor was released in an almost pure form from bacteria incubated at elevated pH, and could be isolated by IgA-Sepharose affinity chromatography. The sequence of the N-terminal 19 amino acid residues was unique. The receptor preferentially binds IgA of human origin, as shown in immunoblotting experiments with purified IgA from nine different species. The affinity constant of the purified receptor for serum IgA was determined to be 3.5 x 10(8) M-1, but for secretory IgA it was too low to allow determination. This result indicates that secretory component and/or J chain interferes with the binding of IgA to this type of bacterial receptor, which may be one of the physiological functions of these polypeptides. A reduction in affinity was also observed for another complexed form of IgA, alpha 1-microglobulin-IgA. The group B receptor is antigenically unrelated to the IgA receptor from group A streptococci (protein Arp), but competitive inhibition experiments indicate that they bind to the same region in IgA. The implications of these findings, and the biological role of bacterial IgA receptors, are discussed.

Amino Acid Sequence↗
PubMed1990

An intriguing member of the lipocalin protein family: alpha 1-microglobulin.

The plasma protein alpha 1-microglobulin is a member of the lipocalin protein superfamily. In the last few years, the work on alpha 1-microglobulin has given unexpected and promising new results. Of particular interest are its molecular association with immunoglobulin A and with proteinase inhibitors, and its interactions with the immune system.

Alpha-Globulins↗
PubMed1990

Alpha 1-microglobulin is mitogenic to human peripheral blood lymphocytes. Regulation by both enhancing and suppressive serum factors.

Human alpha 1-microglobulin (alpha 1-m), a 26 kilodalton serum glycoprotein, was found to exert mitogenic effects on human peripheral blood lymphocytes (PBL) in serum-free medium. Purified T cells, but not B cells, responded with proliferation to alpha 1-m, but only in the presence of monocytes. The mitogenic activity could be partially neutralized by a mouse monoclonal antibody against alpha 1-m. The mitogenicity was species-specific, since alpha 1-m homologues from rats, guinea pigs and rabbits had no effect on human PBL. In a previous study, no effect of alpha 1-m was seen on PBL in the presence of 20% serum, and, therefore, we studied the influence of different concentrations of serum on the alpha 1-m-induced mitogenicity. Thus, human serum enhanced the mitogenic effects of alpha 1-m on human PBL at 1% concentration (v/v) and suppressed the effects at 10%. The suppressing effect of serum at 10%, but not the enhancing effect at 1%, seemed to be conserved among several species. To test the effect of serum proteins of different molecular sizes, human autologous serum was separated by gel chromatography on Sephadex G-200 into four fractions. Fractions 1 and 2 (roughly containing proteins larger than 100 kilodaltons) suppressed the mitogenic effects of alpha 1-m, while fractions 3 and 4 enhanced the stimulation by alpha 1-m, at 0.5% and concentrations above. It is concluded that the mitogenic effect of alpha 1-m on lymphocytes is regulated by several serum factors, both enhancing and suppressive, that does not have any proliferative effect of their own. It can be speculated that the balance between enhancing and suppressing co-factors in the blood determines the degree of the stimulation of lymphocytes by alpha 1-m. This is compatible with an immunomodulatory role for alpha 1-m, in spite of its relatively constant plasma levels in health and disease.

Alpha-Globulins↗
PubMed1990

Mitogenic effect of alpha 1-microglobulin on mouse lymphocytes. Evidence of T- and B-cell cooperation, B-cell proliferation, and a low-affinity receptor on mononuclear cells.

Human alpha 1-m microglobulin (alpha 1-m), a low molecular weight plasma protein, was found to exert mitogenic effects on mouse lymphocytes from lymph nodes and spleen. The stimulatory effects appeared to be strain-restricted: alpha 1-m induced a varying degree of proliferation of lymphocytes from three strains, whereas one strain responded poorly. Experiments with lymphocyte subpopulations showed only weak stimulatory effects of alpha 1-m on purified T and B lymphocytes cultivated alone. The addition of mitomycin-treated cells of the other subpopulation could not restore the proliferative responses in either T or B lymphocytes. Strong stimulations were recorded only when both T and B lymphocytes were present, indicating that the T and B lymphocytes cooperate to achieve the proliferation. However, FACS studies on cultured splenocytes indicated that the proliferating cells are predominantly B lymphocytes. These data extend our earlier findings of a mitogenic effect of alpha 1-m on guinea pig lymphocytes. Furthermore, results were obtained indicating the presence of a receptor on mononuclear cells. Iodine-labelled alpha 1-m was bound to mononuclear cells prepared from spleens, and the binding could be blocked by an excess of non-labelled alpha 1-m. Scatchard plotting of the data gave an equilibrium constant of 0.7 x 10(5)/M for the binding between alpha 1-m and the receptor. Together with the documented inhibitory activity of alpha 1-m on antigen-driven proliferation of lymphocytes, these results suggest an immunoregulatory role for alpha 1-m.

Alpha-Globulins↗
PubMed1989

Protein L: an immunoglobulin light chain-binding bacterial protein. Characterization of binding and physicochemical properties.

Protein L, a cell wall molecule of the bacterial species Peptostreptococcus magnus with affinity for immunoglobulin (Ig) light chains, was isolated after solubilization of the bacterial cell walls with mutanolysin or from the culture medium by a single affinity chromatography step on human IgG-Sepharose. A major protein band with an apparent molecular weight of 95,000 was obtained from both sources. The protein from the growth medium was size heterogeneous. From 1 ml of packed bacteria was prepared 0.92 mg of the mutanolysin-solubilized protein L (73% yield), whereas 4.1 mg of spontaneously released protein L (49% yield) was purified from the corresponding culture medium. The Mr of protein L was estimated to 76,000 by gel chromatography in 6 M guanidine HCl. Using this Mr value, the Stokes radius and the frictional ratio of protein L were determined to 4.74 nm and 1.70, respectively, suggesting an elongated fibrous molecule. No disulfide bond or subunit structure could be shown. The amino-terminal amino acid sequences of the whole protein and two internal non-IgG-binding tryptic fragments were determined and found to be unique. One of the tryptic fragments showed homology (40% identical residues) to a sequence within the cell wall-binding region of protein G, the Fc-binding protein of group C and G streptococci. The binding specificity of protein L was directed to the light chains of immunoglobulins; the affinity constant for polyacrylamide-coupled kappa-chains was 1.5 x 10(9) M-1 and for IgG, IgA, and IgM around 1 x 10(10) M-1. Maximal binding was achieved between pH 7 and 10. The binding to lambda-chains was too weak for determination of the affinity constant. 125I-Protein L was also shown to bind to mouse immunoglobulins. It could be used for detection of antigen-bound polyclonal and monoclonal antibodies in Western blots. This shows that the protein L/light chain reaction was not obstructed by occupation of the antigen-binding site. Finally, protein L and kappa-chains of human Ig formed precipitates upon double immunodiffusion analysis, an indication of at least two binding sites on protein L.

Amino Acid Sequence↗
PubMed1989

Ig-binding bacterial proteins also bind proteinase inhibitors.

Protein G is a streptococcal cell wall protein with separate binding sites for IgG and human serum albumin (HSA). In the present work it was demonstrated that alpha 2-macroglobulin (alpha 2M) and kininogen, two proteinase inhibitors of human plasma, bound to protein G, whereas 23 other human proteins showed no affinity. alpha 2M was found to interact with the IgG-binding domains of protein G, and in excess alpha 2M inhibited IgG binding and vice versa. A synthetic peptide, corresponding to one of the homologous IgG-binding domains of protein G, blocked binding of protein G to alpha 2M. Protein G showed affinity for both native and proteinase complexed alpha 2M but did not bind to the reduced form of alpha 2M, or to the C-terminal domain of the protein known to interact with alpha 2M receptors on macrophages. Binding of protein G to alpha 2M and kininogen did not interfere with their inhibitory activity on proteinases, and the interaction between protein G and the two proteinase inhibitors was not due to proteolytic activity of protein G. The finding that protein G has affinity for proteinase inhibitors was generalized to comprise also other Ig binding bacterial proteins. Thus, alpha 2M and kininogen, were shown to bind both protein A of Staphylococcus aureus and protein L of Peptococcus magnus. The results described above suggest that Ig-binding proteins are involved in proteolytic events, which adds a new and perhaps functional aspect to these molecules.

Bacterial Proteins↗
PubMed1989

Receptor for IgA in group A streptococci: cloning of the gene and characterization of the protein expressed in Escherichia coli.

The gene for an IgA-binding protein from a group A streptococcal strain was cloned and expressed in Escherichia coli. The IgA-binding protein, called protein Arp, was purified on IgA-Sepharose, allowing complete purification in a single step. Analysis of protein Arp by Western immunoblotting demonstrated a major IgA-binding band, with an apparent molecular weight of 42 kD. The purified protein was shown to bind serum IgA and secretory IgA, as well as monoclonal IgA of both subclasses. There was no binding to IgM, IgD or IgE, but a weak binding to IgG. Inhibition experiments with whole bacteria indicated that IgA and IgG bind at separate sites. Experiments with immunoglobulin fragments showed that protein Arp binds to the Fc region of both IgA and IgG. The equilibrium constant of the reaction between protein Arp and polyclonal human IgA was determined to be 5.6 x 10(8) M-1. Amino acid sequencing of protein Arp demonstrated a direct repeat of 7 amino acids in the NH2-terminal region, a feature previously found in several streptococcal M proteins. This suggests that protein Arp, like M proteins, may be a streptococcal virulence factor.

Amino Acid Sequence↗
PubMed1988

Isolation and characterization of a 14-kDa albumin-binding fragment of streptococcal protein G.

Protein G, a streptococcal cell wall protein, has separate binding sites for human albumin and IgG. Streptococci expressing protein G were treated with the bacteriolytic agent mutanolysin. Several IgG- and human serum albumin (HSA)-binding peptides were identified in the material thus solubilized and one of these, a 14-kDa peptide, was found to bind HSA but not IgG in Western blot experiments. This molecule was purified by affinity chromatography on Sepharose coupled with HSA followed by gel filtration on Sepharose 6B and a final affinity chromatography on IgG-Sepharose, by which low Mr W(15 to 20 kDa)IgG-binding peptides were removed. In different binding experiments the purified 14-kDa peptide bound exclusively HSA and the equilibrium constant between the peptide and HSA was determined to be 3.4 X 10(8) M-1. The relation between the 14-kDa molecule and protein G was studied by analyzing the N-terminal amino acid sequence of the peptide and comparing it with the previously determined protein G sequence. The 40 N-terminal amino acids were found to be identical with an amino acid sequence starting at position 62 in the protein G molecule. These and previous data enabled us to locate the albumin binding to the repetitively arranged domains in the N-terminal half of the protein G molecule.

Bacterial Proteins↗
PubMed1988

Enzyme linked immunosorbent assay using alkaline phosphatase conjugated with streptococcal protein G.

Protein G, an IgG-binding protein, purified from the surface of group G streptococci, was coupled to alkaline phosphatase. The conjugate was used for detection of polyclonal goat and rabbit antibodies and monoclonal mouse IgG1, IgG2a and IgG2b in an enzyme-linked immunosorbent assay. A two-step coupling procedure was used, in which glutaraldehyde was allowed to react with the enzyme, excess glutaraldehyde was then removed by dialysis, and finally protein G added to the glutaraldehyde-activated and polymerized alkaline phosphatase. The activity and yield of the conjugates were then tested in an enzyme-linked immunosorbent assay. Coupling of 25 micrograms protein G to 5 mg alkaline phosphatase gave a conjugate which could be used for more than 10,000 determinations with maximal antibody binding giving an absorbance of 2.0. Under these conditions, there was no need for separation of the reactants before using the protein G-alkaline phosphatase complex.

Alkaline Phosphatase↗
PubMed1987

Structural relationship between alpha 1-microglobulin from man, guinea-pig, rat and rabbit.

Rabbit alpha 1-microglobulin was purified from the urine of sodium-chromate-treated animals by the use of gel chromatography on Sephadex G-100, affinity chromatography on concanavalin-A--Sepharose and ion-exchange chromatography on DEAE-Sephadex. Rabbit alpha 1-microglobulin had a molecular mass of 25.6 kDa on SDS/polyacrylamide gel electrophoresis. Alpha 1-microglobulin has previously been purified from the urine of humans, guinea-pigs and rats by similar methods, and the molecular masses of the four homologues were compared by SDS/polyacrylamide gel electrophoresis and gel chromatography in a denaturing medium. By these two methods the human homologue was 6 kDa and 3 kDa larger, respectively, than the other three proteins. Endoglycosidase F digestion of alpha 1-microglobulin, followed by SDS/polyacrylamide gel electrophoresis, revealed three protein bands in the human alpha 1-microglobulin sample, and only two bands in guinea-pig, rat and rabbit alpha 1-microglobulin, with a gap between each band of 2.6--2.9 kDa. The amino-terminal amino acid sequences of the four homologues were determined and between 72% and 81% homology was seen. The five amino-terminal amino acids present in the other species were missing in guinea-pig alpha 1-microglobulin. Our results indicate that human alpha 1-microglobulin is substituted with two N-linked oligosaccharides, while only one is attached to each of the other alpha 1-microglobulins, and that the extra glycosylamine-linked oligosaccharide in the human protein is attached to asparagine in position 17. Finally it is shown that all four homologues inhibit antigen stimulation of human lymphocytes, a finding which is consistent with our previous suggestion that the N-linked oligosaccharides carry the immunosuppressive activity of alpha 1-microglobulin.

Alpha-Globulins↗
PubMed1987

Definition of IgG- and albumin-binding regions of streptococcal protein G.

Protein G, the immunoglobin G-binding surface protein of group C and G streptococci, also binds serum albumin. The albumin-binding site on protein G is distinct from the immunoglobulin G-binding site. By mild acid hydrolysis of the papain-liberated protein G fragment (35 kDa), a 28-kDa fragment was produced which retained full immunoglobulin G-binding activity (determined by Scatchard plotting) but had lost all albumin-binding capacity. A protein G (65 kDa), isolated after cloning and expression of the protein G gene in Escherichia coli, had comparable affinity to immunoglobulin G (5-10 X 10(10)M-1), but much higher affinity to albumin than the 35- and 28-kDa protein G fragments (31, 2.6, and 0 X 10(9)M-1, respectively). The amino-terminal amino acid sequences of the 65-, 35-, and 28-kDa fragments allowed us to exactly locate the three fragments in an overall sequence map of protein G, based on the partial gene sequences published by Guss et al. (Guss, B., Eliasson, M., Olsson, A., Uhlen, M., Frej, A.-K., Jörnvall, H., Flock, J.-I., and Lindberg, M. (1986) EMBO J. 5, 1567-1575) and Fahnestock et al. (Fahnestock, S. R., Alexander, P., Nagle, J., and Filpula, D. (1986) J. Bacteriol. 167, 870-880). In this map could then be deduced the location of three homologous albumin-binding regions and three homologous immunoglobulin G-binding regions.

Amino Acid Sequence↗
PubMed1987

Cross-reacting monoclonal anti-alpha 1-microglobulin antibodies produced by multi-species immunization and using protein G for the screening assay.

In order to generate monoclonal antibodies (MAb) directed against the low molecular weight glycoprotein alpha 1-microglobulin, a BALB/c mouse was immunized with a mixture of human, guinea pig, rat and rabbit alpha 1-microglobulin homologues (multi-species immunization) and boosted several times. On day 194, the mouse splenocytes were fused to SP2/0 myeloma cells. The resulting hybridomas were screened for anti-alpha 1-microglobulin activity against the alpha 1-microglobulin mixture or against the individual homologues. For this screening, protein G (the newly described IgG-binding streptococcal protein) was used in a solid-phase radioimmunoassay. The binding of protein G to immobilized antigen-antibody complexes was enhanced by pre-incubation with rabbit anti-mouse immunoglobulin G. The result was a panel of nine established hybridoma lines, all producing unique monoclonal antibodies, of IgG1 or IgG2a class, to alpha 1-microglobulin. The antibodies were not only reactive in solid-phase radioimmunoassay, but they could also immunoprecipitate 125I-labeled soluble alpha 1-microglobulin. Moreover, they reacted specifically with the alpha 1-microglobulin band in Western blots of urinary proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Such monoclonal antibodies are potentially valuable reagents for the further characterization of alpha 1-microglobulin.

Alpha-Globulins↗