Human B cell proliferation is stimulated by interleukin 2

The proliferation of human B cells was studied for response to interleukin 2 (IL-2) produced in Escherichia coli using recombinant DNA technology. The IL-2 was found to be an homogenous preparation by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting using the anti-IL-2 monoclonal antibody DMS-1. IL-2 was found to stimulate B cell proliferation. Activation of the B cells using anti-IgM antibodies increased this response. Resting T cells from the same donors were found to be less reactive to IL-2. The results suggest that human B cell proliferation can be stimulated by IL-2 alone.

Immunoblotting with monoclonal antibodies: loss of immunoreactivity with human immunoglobulins arises from polypeptide chain separation

Immunoblotting has been used to study the antigen binding characteristics of 5 monoclonal antibodies (Mc/Abs) against human Ig (1 anti-kappa, 2 anti-gamma and 2 anti-delta chain. Of the 4 Mc/Abs only 1 (the anti-kappa chain Mc/Ab) reacted with its antigen when blotted from reducing SDS polyacrylamide gels. However, the 4 Mc/Abs which recognise immunoglobulin heavy chains were able to bind their antigens when blotted from native or non-reducing SDS gels. The lack of reactivity of the latter Mc/Abs in blots from reduced SDS gels may be attributed to the separation of Ig which occurs during electrophoresis after the -S-S- bonds are broken. It may be concluded that the conformation of Ig heavy chains is considerably altered when Ig molecules are disrupted and Ig chains separated, and several heavy chain determinants are lost during this process. Therefore determinants recognised by the anti-heavy chain Mc/Abs are most likely to be of the 'conformational' type whereas the anti-light chain Mc/Ab may well recognise a purely sequential determinant.

Production and characterization of monoclonal antibodies to beta-galactoside-binding lectin of bovine heart muscle. Direct evidence that haemagglutinating activity is associated with a 13kDa protein

With the aim of obtaining monospecific antibodies against the beta-galactoside-binding lectin of bovine heart muscle, spleen cells from Lou rats immunized with lectin were fused with the rat myeloma line Y3.Ag1.2.3. Two immunoglobulin M (IgM)-producing clones, designated NIBy 142-36/8 and NIBy 143-9/5, derived from separate fusions, were used to generate ascites containing high-titre binding activity against the 13kDa component in preparations of lectin. Direct evidence that haemagglutinating activity is associated with the 13kDa protein was obtained by the specific elution of 13kDa polypeptides with haemagglutinating activity from an immobilized antibody adsorbent. Solid-phase radiobinding assays and immunoblotting of isolated lectins and/or muscle homogenates confirmed the earlier indications with conventional antisera that the beta-galactoside-binding lectins of bovine, human and monkey muscle tissue are antigenically related.

Intrasplenic primary immunization for the production of monoclonal antibodies

A novel immunization procedure for eliciting monoclonal antibodies ( McAbs ) is described. With intrasplenic inoculation only small amounts of immunogen are required. As little as 20 micrograms of protein antigen or 2.5 X 10(5) cells have been found sufficient to immunize mice or rat spleen cells for the production of specific McAbs . A high proportion of hybridomas secreting McAbs against cell surface antigens and soluble proteins has been obtained with this immunization procedure. The system could facilitate McAb production in many instances in which only small quantities of immunogen are available.

Molecular identity, distribution and heterogeneity of glial fibrillary acidic protein: an immunoblotting and immunohistochemical study of Schwann cells, satellite cells, enteric glia and astrocytes

Glial fibrillary acidic protein has been firmly established as the predominant component of astrocyte intermediate filaments. It has also been detected immunohistochemically in the glial cells of the enteric nervous system and some Schwann cells in the P.N.S. The molecular identity of this GFAP immunoreactivity in the P.N.S. has so far not been investigated. This study compares GFAP in the C.N.S. and P.N.S. of adult rats both immunochemically and immunohistochemically. Using SDS polyacrylamide gel electrophoresis combined with immunoblotting, and a polyclonal antiserum to brain GFAP, we show that the peripheral GFAP immunoreactivity resides in a polypeptide with a molecular weight of 49 kd, which is identical to that of rat brain GFAP. Furthermore, we find that this GFAP reactivity can be detected immunohistochemically in Schwann cells in a wide variety of nerves in the P.N.S. and in some satellite cells in both sensory and sympathetic ganglia, in addition to enteric glia. The pattern of distribution of GFAP filaments in Schwann cells suggests that, in the nerves surveyed, they may be expressed by most or all non-myelin forming Schwann cells but not by myelin-forming Schwann cells. We also show, using a monoclonal antibody to GFAP (anti-GFAP-3) in both immunohistochemical and immunoblotting studies, that the GFAP found in most peripheral glia is not identical to that of astrocytes since it lacks an antigenic determinant, defined by this monoclonal antibody, which is present in astrocytes. An exception to this finding is seen in the myenteric plexuses where immunohistochemically detectable GFAP is found in some, but not all, of the enteric glia, using the monoclonal antibody. Thus, the results suggest that GFA polypeptides may be a heterogeneous group, that share some common determinants and a common molecular weight, and show a widespread and complex distribution in the glia of both the C.N.S. and P.N.S.

Single shot intrasplenic immunization: an advantageous procedure for production of monoclonal antibodies specific for human fibrin fragments

We describe the use of the single shot intrasplenic immunization technique as a particularly effective procedure for the production of specific monoclonal antibodies against a high molecular weight antigen. We found that with this technique several different, completely specific monoclonal antibodies could be produced against high molecular weight crosslinked fibrin degradation products. These results contrasted with those obtained using conventional multidose immunization, which only produced monoclonal antibodies that were cross-reactive with fibrinogen and/or noncrosslinked fibrin degradation products.

Elucidation of the antigenic determinant in lipotropin for two monoclonal antibodies

Two monoclonal antibodies were found to give enhanced affinity for beta-lipotropin when mixed, as evidenced by competitive radioimmunoassay. Both monoclonals were found to react with a pentapeptide Ala-Glu-Leu-Glu-Tyr, which is a sequence of high local hydrophilicity within the N-terminal section of beta-lipotropin.

Detection and affinity purification of beta-endorphin precursors using a monoclonal antibody

A monoclonal antibody to porcine beta-lipotropin has been produced which binds to the N-terminal (gamma-lipotropin) portion of the molecule. The antibody can be used to detect beta-lipotropin as well as other beta-endorphin precursors (predominantly a Mr 38 000 polypeptide) using radiobinding assay or the immunoblotting technique. Purification of the peptides can be readily achieved by affinity chromatography using the monoclonal antibody covalently bound to Sepharose 4B. As the antibody recognises the N-terminal part of beta-lipotropin, it can be used to detect and purify beta-lipotropin and other beta-endorphin precursors in the presence of beta-endorphin.

Immunochemical studies of polioviruses: identification of immunoreactive virus capsid polypeptides

Investigation of the immunological reactions with individual poliovirus capsid polypeptides of antisera and monoclonal antibodies raised against poliovirus type 3 antigens are described. Virus polypeptides were separated by electrophoresis, transferred electrophoretically to nitrocellulose sheets and treated with antibody preparations. Antibody binding specifically to the virus polypeptides was then detected by application of 125I-labelled anti-immunoglobulin followed by autoradiography. The technique readily enabled the identification of the polypeptides recognized by the antibody. Antibodies present in polyclonal, type-specific neutralizing sera to poliovirus type 3 bound to the two largest capsid polypeptides (VP1 and VP2) of the homotypic poliovirus, and also to the VP1 of poliovirus type 1 and type 2. There was no obvious difference between the antibody binding patterns obtained with neutralizing and non-neutralizing antisera or between C-specific and D-specific antisera. VP1 appeared to be the immunodominant virus polypeptide. Among monoclonal antibodies specific for the C antigen of poliovirus type 3, a proportion reacted homotypically with the VP1 of poliovirus type 3. Other monoclonal antibodies of C antigen or D antigen specificity, or which reacted both with D and C antigens, some of which had potent virus-neutralizing activity, failed to give demonstrable binding reactions. The non-correlation of neutralization and immunoblot reactivity suggests that sequence determinants alone do not mediate virus neutralization which may depend on antigenic determinants specified by complex conformational arrangements of the virus capsid proteins.

All classes of intermediate filaments share a common antigenic determinant defined by a monoclonal antibody

We have produced a monoclonal antibody that reacts with all classes of intermediate filaments in immunofluorescence assays, including glial filaments in astrocytes, neurofilaments in axons, tonofilaments in epithelial PtK2 cells and intermediate filaments in fibroblasts. It also binds to Z lines in skeletal muscle. In SDS-polyacrylamide gels, the antibody binds to most and perhaps all of the major intermediate filament proteins that have been previously defined, including glial fibrillary acidic protein, the three vertebrate neurofilament proteins (the "neurofilament triplet"), vimentin, desmin, several cytokeratins and the neurofilament proteins of squid and the marine worm Myxicola. In addition, the antibody binds to a protein with an approximate molecular weight of 66,000 that may be a component of all intermediate filaments. These findings suggest that all vertebrate and invertebrate intermediate filament proteins share a common antigenic determinant and raise the possibility that all intermediate filaments contain a 66,000 molecular weight protein.

Specific neuronal localization by immunofluorescence of 10 nm filament polypeptides

Rabbit antisera have been produced to bovine brain 10 nm filament preparations and to purified polypeptide constituents of brain 10 nm filaments. Antisera to the former preparation stain both neurons and astrocytes, whereas antisera to two polypeptides of mol. wt 155 000 and 210 000 are neuron specific. It is therefore concluded that these latter polypeptides are components of neurofilaments and the mixed staining pattern obtained with the antisera to the whole brain 10 nm filament preparation is due to the presence in this material of a mixture of neurofilaments and glial filaments which are thus biochemically distinct forms of 10 nm filament.

The polypeptides of isolated brain 10nm filaments and their association with polymerized tubulin

Brain 10 nm filaments were isolated from bovine, rabbit and rat brains by a modification of an existing procedure. The overall polypeptide composition of these preparations was similar to that previously reported for brain neurofilaments. In addition to the major polypeptide component, which has mol. wt. approx. 50 000, three other polypeptides with chain mol. wts. approx. 210 000, 155 000 and 70 000, which correspond to peripheral-nerve neurofilament polypeptides, were consistently found to be present. The mol. wt.-50 000 species was found to be heterogeneous and may contain a component derived from the mol. wt. 70 000 polypeptide. The three higher-molecular-weight polypeptides did not appear to be obviously homologous or to be homologous with myosin or Myxicola neurofilament polypeptides. These same three higher-molecular-weight components were shown to be identical with the polypeptides probably responsible for the 10 nm filaments formed during the early cycles of the tubulin-purification protocol.

Purification and serological studies of human alpha-L-fucosidase in the normal and fucosidosis states

An antiserum has been raised to purified alpha-L-fucosidase. Levels of cross-reaction with serum of two unrelated fucosidosis patients and normal individuals with low activity are consistent with the presence of very low amounts of normal enzyme. Similarly no cross-reacting material could be found in cultured fibroblasts from fucosidosis patients. It is deduced that in these cases there is no production of mutant enzyme in quantities comparable to normal levels. Some observations on the interrelations of fucosidases I and II are reported.

Lysosomal glycosidase activities in human hair roots

The levels of three lysosomal glycosidase, alpha-D-mannosidase, a-L-fucosidase and beta-D-hexosaminidase have been determined in normal hair roots and in hair roots obtained from a patient with mannosidosis. The most active glycosidase in normal hair roots was beta-D-hexosaminidase, followed by alpha-L-fucosidase and alpha-D-mannosidase. There was no alpha-D-mannosidase activity in the hair roots of the patient with mannosidosis. The significance of these results is discussed in relation to the detection of lysosomal storage diseases.