Characterization of a variant of carcinoembryonic antigen (CEA) using monoclonal and polyclonal anti-CEA antibodies

A variant of the carcinoembryonic antigen (CEA) with lower molecular weight than a CEA reference preparation has been separated from CEA. Using a polyclonal, spleen absorbed anti-CEA antiserum, the variant crossreacts with reference CEA in immunodiffusion. The CEA-activity of the variant has been demonstrated using an enzyme-immunoassay with monoclonal CEA specific antibodies. There is sufficient immunological evidence that this variant is a distinct antigen different from the crossreactive antigens described so far. The reactivity of the polyclonal anti-CEA antiserum with the CEA variant was abolished by absorption against the immobilized variant.     

Adsorption equilibrium in immuno-affinity chromatography with polyclonal and monoclonal antibodies

The effects of pH, ionic strength, anion species, and antibody concentration on the adsorption equilibrium between immobilized antibodies and antigens were studied by use of anti-BSA, anti-HSA, anti-BlgG, and monoclonal anti-HSA coupled to Sepharose 4B. The polyclonal antibodies possessed average binding affinities of the order of 10(8)M(-1), and the heterogeneity was accounted for by assuming a normal distribution of the free energy of antibody-antigen combination. The monoclonal antibody, on the other hand, showed a homogeneous affinity of the Langmuir type. Bound antigens could be eluted by lowering pH or adding a chaotropic anion, and their purity was very high. The antibody ligand was sufficiently stable for repeated use.     

Heterogeneity of keratin distribution in the oral mucosa and skin of mammals as determined using monoclonal antibodies

Summary The immunohistochemical localization of keratins in the oral epithelia of several mammals was investigated using the monoclonal antibodies to keratins, PKK1 (41–56 kilodaltons) and KL1 (55–57 kilodaltons). The staining patterns obtained in different locations of the oral mucosa and of the skin epidermis were compared. In the papillae on the dorsal surface of the tongue, some areas exhibited marked PKK1 staining, while other area were PKK1 negative. In general, rodent oral epithelia were negative for PKK1 in the basal layer, while comparatively strong PKK1 staining was observed in cells of the upper spinous layer. In the epidermis, positive PKK1 reactions were confined to the basal layer, while KL1 staining was occasionally seen in the basal layer of oral epithelia. In cats, dogs, and monkeys, different PKK1 and KL1 binding patterns were observed in oral epithelia. Also, the distribution in oral epithelia differed from that seen in the epidermis of these animals. In the epidermis, the distribution of PKK1 and KL1 was regular, with PKK1 usually being confined to the basal layer, while KL1 binding was found in the spinous and granular cell layers, and was dependent on the degree of keratinization. In the animals studies, keratin expression as detected by PKK1 and KL1-was different in the skin epidermis and oral epithelia, and the localization of these keratins differed in the various types of oral mucosa.     

Heterogeneity of keratin distribution in the oral mucosa and skin of mammals as determined using monoclonal antibodies

The immunohistochemical localization of keratins in the oral epithelia of several mammals was investigated using the monoclonal antibodies to keratins, PKK1 (41-56 kilodaltons) and KL1 (55-57 kilodaltons). The staining patterns obtained in different locations of the oral mucosa and of the skin epidermis were compared. In the papillae on the dorsal surface of the tongue, some areas exhibited marked PKK1 staining, while other area were PKK1 negative. In general, rodent oral epithelia were negative for PKK1 in the basal layer, while comparatively strong PKK1 staining was observed in cells of the upper spinous layer. In the epidermis, positive PKK1 reactions were confined to the basal layer, while KL1 staining was occasionally seen in the basal layer of oral epithelia. In cats, dogs, and monkeys, different PKK1 and KL1 binding patterns were observed in oral epithelia. Also, the distribution in oral epithelia differed from that seen in the epidermis of these animals. In the epidermis, the distribution of PKK1 and KL1 was regular, with PKK1 usually being confined to the basal layer, while KL1 binding was found in the spinous and granular cell layers, and was dependent on the degree of keratinization. In the animals studies, keratin expression--as detected by PKK1 and KL1--was different in the skin epidermis and oral epithelia, and the localization of these keratins differed in the various types of oral mucosa.     

Characterization of Chlamydia trachomatis antigens with monoclonal and polyclonal antibodies

We used monoclonal antibodies (MAbs) to examine the antigenic specificity and biologic function of several Chlamydia trachomatis antigens. Thirteen distinct MAbs to eight C. trachomatis antigens were produced. Six MAbs reacted with unique epitopes on the major outer membrane protein (MOMP) and two of these had neutralizing activity. MAbs were produced to each of the chlamydial antigens with molecular masses of 10, 29, 32, 57, 60, 70, and 75 kilodaltons (kDa). These MAbs showed species and genus specificity in an immunoblot assay. None of the MAbs had neutralizing activity. The epitopes recognized on MOMP, 29-, and 10-kDa (presumably lipopolysaccharide) antigens were surface exposed. MAbs to the 75-kDa, 57-kDa, and MOMP antigens were used for immunoaffinity purification of these antigens to produce monospecific antisera in mice. With polyclonal sera, we found that the 75-kDa antigen was also immunoaccessible and that antibody to MOMP and 75-kDa antigens neutralized C. trachomatis infectivity. We conclude that, in addition to MOMP and lipopolysaccharide, antigens with molecular masses of 75 and 29 kDa are surface exposed. Antibodies to MOMP and 75-kDa antigens can neutralize the organism in vitro.     

Immunogold labeling of blood-group antigens in human salivary glands using monoclonal antibodies and the streptavidin-biotin technique

We investigated the localization of blood-group antigens A, B, and H in human labial salivary and submandibular glands by applying a postembedding immunogold method using monoclonal antibodies in combination with the streptavidin-biotin bridge technique. The H, A, and B antigens were only detected in mature secretory granules (SGs), which were mainly found in cells in the late phase of the maturation cycle. In immature SGs, which were present in cells in the early or middle phases of the maturation cycle, these antigens were not detected. All other cytoplasmic organelles were not labeled by the monoclonal antibodies used. In blood-group-O secretors, H antigen was present in almost all of the mature SGs. In blood-group-A secretors, the labeling for H antigen exhibited a mosaic-like pattern, i.e. only some of the mature SGs contained H antigen. With respect to the A and B antigens, a similar mosaic-like pattern of staining was observed in blood-group-A and -B secretors, respectively. To the best of our knowledge, this is the first time that the distribution of blood-group antigens A, B, and H in human tissues has been demonstrated at the electron-microscope-level using monoclonal antibodies.     

Immunogold labeling of blood-group antigens in human salivary glands using monoclonal antibodies and the streptavidin-biotin technique

Summary We investigated the localization of blood-group antigens A, B, and H in human labial salivary and submandibular glands by applying a postembedding immunogold method using monoclonal antibodies in combination with the streptavidin-biotin bridge technique. The H, A, and B antigens were only detected in mature secretory granules (SGs), which were mainly found in cells in the late phase of the maturation cycle. In immature SGs, which were present in cells in the early or middle phases of the maturation cycle, these antigens were not detected. All other cytoplasmic organelles were not labeled by the monoclonal antibodies used. In blood-group-O secretors, H antigen was present in almost all of the mature SGs. In blood-group-A secretors, the labelling for H antigen exhibited a mosaic-like pattern, i.e. only some of the mature SGs contained H antigen. With respect to the A and B antigens, a similar mosaic-like pattern of staining was observed in blood-group-A and-B secretors, respectively. To the best of our knowledge, this is the first time that the distribution of blood-group antigens A, B, and H in human tissues has been demonstrated at the electron-microscope-level using monoclonal antibodies.     

Tissue distribution of cytochrome c oxidase isoforms in mammals. Characterization with monoclonal and polyclonal antibodies

Monoclonal and polyclonal antibodies specific to the two isoforms of subunit VIa of bovine cytochrome c oxidase were generated and used to study the tissue distribution of this subunit pair in beef, human and rat. The so-called H-(heart) form was found exclusively in heart and skeletal muscle, whereas the so-called L-(liver) form was the only isoform present in brain, kidney, liver and smooth muscle. Little or no L-form was detected in skeletal muscle. In bovine heart no subunit VIa-L was detected, while in human heart the subunit VIa-H and VIa-L isoforms were present in roughly equal proportions. These results imply that, in humans, the deficiency of a subunit VIa isoform may have a different effect on the physiology of heart then on the physiology of skeletal muscle.     

Production and specificity of monoclonal antibodies and polyclonal antibodies to Escherichia coli

Monoclonal antibodies were produced to whole cells of heat-treated Escherichia coli. Balb/c mice were immunized with a pool of five strains of heat-treated E. coli , and the resulting hybridomas were screened by indirect immunoassay. E. coli strains other than those used for immunization were used for screening to detect hybridomas producing antibody that reacted with a large number of E. coli strains. Of 864 hybridomas, 32 reacted strongly with either two or all three of the strains used for screening; 15 were successfully cloned. Antibody from hybridoma 6H2 reacted with 35 of 68 (51%) E. coli ; of 13 non- E. coli tested, only Enterobacter agglomerans was weakly positive. Hybridoma 9B12 antibody reacted with all six E. coli tested. Hybridoma 9B12, however, stopped producing antibody. Five hybridomas produced antibody which reacted with a majority of the bacteria tested whereas antibodies from two other hybridomas reacted with several E. coli and non- E. coli. Polyclonal antibodies produced to two strains of E. coli varied in the numbers of E. coli with which they reacted; both antisera cross-reacted with several non- E. coli.     

Production and specificity of monoclonal antibodies and polyclonal antibodies to Escherichia coli

Monoclonal antibodies were produced to whole cells of heat-treated Escherichia coli. Balb/c mice were immunized with a pool of five strains of heat-treated E. coli, and the resulting hybridomas were screened by indirect immunoassay. E. coli strains other than those used for immunization were used for screening to detect hybridomas producing antibody that reacted with a large number of E. coli strains. Of 864 hybridomas, 32 reacted strongly with either two or all three of the strains used for screening; 15 were successfully cloned. Antibody from hybridoma 6H2 reacted with 35 of 68 (51%) E. coli; of 13 non-E. coli tested, only Enterobacter agglomerans was weakly positive. Hybridoma 9B12 antibody reacted with all six E. coli tested. Hybridoma 9B12, however, stopped producing antibody. Five hybridomas produced antibody which reacted with a majority of the bacteria tested whereas antibodies from two other hybridomas reacted with several E. coli and non-E. coli. Polyclonal antibodies produced to two strains of E. coli varied in the numbers of E. coli with which they reacted; both antisera cross-reacted with several non-E. coli.     

Production of human monoclonal and polyclonal antibodies in TransChromo animals

We have developed TransChromo (TC) technology, which enables the introduction of megabase-sized segments of DNA into cells. We have used this approach to derive mice that carry megabases of human DNA by the use of a human chromosome fragment (HCF) as a vector. TC technology has been applied to the construction of the TC Mouse,trade mark which incorporates entire human immunoglobulin (hIg) loci. TC Mouse expresses a fully diverse repertoire of hIgs, including all the subclasses of IgGs (IgG1-G4). Immunization of the TC Mouse with various human antigens produced antibody responses comprised of human antibodies. Furthermore, it was possible to obtain hybridoma clones expressing fully human antibodies specific for the target human antigen. However, because of the instability of the Igkappa locus-bearing HCF2, the efficiency of hybridoma production was less than one-tenth of that observed in normal mice. An instant solution to this problem was to cross-breed the Kirin TC Mouse carrying the HCF14, which was stable in mouse cells, with the Medarex YAC-transgenic mouse carrying about 50% of the hIgVkappa gene segments as a region that is stably integrated into the mouse genome. The resulting mouse, dubbed the KM Mouse, performed as well as normal mice with regard to immune responsiveness and efficiency of hybridoma production. Another application of TC technology is the production of polyclonal antibodies in large animals such as chickens and cows. To test the efficacy of human polyclonal antibodies derived from TC animals, feasibility studies were performed using antisera and purified gamma-globulin from TC mice immunized with Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), or Japanese encephalitis virus (JEV). The TC mouse-derived antisera and gamma-globulin showed a much higher titer and efficacy in terms of the neutralizing activity of the pathogens in vitro and in vivo than either human serum or gamma-globulin prepared from human blood.     

Distribution of the carcinoembryonic antigen CEA in gastric lesions. Immunohistochemical testing of three novel monoclonal antibodies

Three mouse monoclonal antibodies MAB (CEA 12-140-1, -2 and -4) raised against different CEA epitopes were tested in 32 gastric adenocarcinomas (18 intestinal type and 14 diffuse type) and 34 gastric lesions with severe and moderate dysplasia. The MAB stained 13, 11 and 13 out of the 14 diffuse carcinomas and 11, 13 and 13 out of the 18 intestinal carcinomas. The dysplastic lesions were positive in 9, 9 and 6 out of 34 cases. Less than half of the cases with metaplastic epithelium adjacent to the carcinomas were also positive for MAB. All MAB showed the same pattern of reactivity without cross-reactivity. Their cumulative staining rate corresponded closely to that of polyclonal CEA antiserum, but the MAB stained more cells. The reactivity was confined to intracytoplasmic vacuoles in diffuse carcinomas and appeared diffusely in the cytoplasm or limited to the cell membrane in intestinal type of carcinomas. Our findings do not indicate CEA to be a reliable marker for malignant transformation in gastric mucosa.     

Using polyclonal and monoclonal antibodies in regulatory testing of biological products

Polyclonal and monoclonal antibodies are often used in regulatory testing of biologicals (vaccines and related products). One of the most common applications for antibody-based immunoassays is as a batch release test. Batch release tests, whether they measure serological responses to vaccination or they quantify individual antigens by in vitro methods, must provide an acceptable estimate of potency of an individual batch of vaccine. Thus, due consideration must be given to the type of antibody used or quantified in such assays. Differences in specificity and avidity may affect the utility of an assay as an indicator of potency; case examples are given to illustrate these concepts. Concerns associated with antigen quantification assays (e.g., reagent denaturation upon binding to solid substrates, and interference from nontarget antigens or additives in a complex vaccine) are also discussed. International efforts to harmonize test methods in recent years have increased the importance of establishing standardized antibodies. Sources of such antibodies and issues associated with the ongoing availability of antibody supplies are described.     

Use of monoclonal and polyclonal antibodies as structural and topographical probes for hepatic epoxide hydrolase

Monoclonal antibodies have been prepared against rat liver epoxide hydrolase (EH), some of which gave precipitation lines on immunodiffusion against pure EH suggesting the presence of repetitive structural domains on the enzyme. Using ELISA, with polyclonal antibodies to rat and rabbit liver EH, reactivity and therefore structural similarities between EH of all species tested, including human, were observed. This was in contrast to immunodiffusion results demonstrating the limitations of the latter technique. Using monoclonal antibodies in ELISA, greatest structural similarity was between rat, mouse, and Syrian hamster EH and relatively little between rat and human. Two of the antibodies reacted with nearly all species tested and may be directed towards critical sites on the enzyme. This and most of the EH molecule would appear to be localised on the cytoplasmic surface of the endoplasmic reticulum.     

The antigenic structure and topography of bacteriorhodopsin in purple membranes as determined by interaction with monoclonal antibodies

The spatial organization and the antigenic structure of the bacteriorhodopsin molecule in the purple membrane were studied by immunochemical techniques. Five monoclonal antibodies directed against exposed parts of the protein molecule in the membrane were prepared and characterized. Antigenic determinants were localized in the bacteriorhodopsin polypeptide chain by analysis of the interaction between monoclonal antibodies and protein fragments. The structure of antigenic determinants was revealed by the interaction of monoclonal antibodies with (i) isolated bacteriorhodopsin fragments further modified by sequential Edman degradation and (ii) derivatives of bacteriorhodopsin obtained biosynthetically or by selective chemical modification. Five antigenic determinants were localized in the following parts of bacteriorhodopsin: < Glu'-Met²⁰ involving one of the 3 amino acid residues of the N-terminal part; Gly³³-Met⁵⁶ involving Asp³⁶ and/or Asp³⁸ and Phe⁴²; Phe¹⁵⁶-Met¹⁶³ involving Phe¹⁵⁶; Glu¹⁹⁴-Leu²⁰⁷ involving Glu¹⁹⁴; Pro²⁰⁰-Leu²⁰⁷.     

Production of highly specific polyclonal and monoclonal antibodies using estradiol-3-O-carboxymethyl ether as hapten

The preparation of high affinity and high specificity polyclonal and monoclonal antibodies to estradiol is described. Monoclonal antibodies were derived from BALB/c mice hyperimmunized with estradiol-3-O-carboxymethyl ether conjugated to bovine serum albumin. Spleen cells were hybridized with mouse myeloma cells. Quite a few monoclonal antibodies showed very good affinity for estradiol. Extended immunization and hyperimmunization were essential for producing a greater number of positive clones secreting high affinity antibodies. Binding constants of the antisera and their cross-reactivities with related steroids were calculated. Both polyclonal and monoclonal antibodies showed very high affinity for estradiol exhibiting little or no cross-reactivities with structurally related steroids indicating that this site of linkage is a good choice for discriminating between differences at the 16-17 position in the D-ring. This monoclonal antibody (44.28.6), having negligible cross-reactivity with estriol and estrone, can be used for diagnostic purposes.     

Immunohistochemical detection of human epidermal growth factor in submandibular glands and their tumors using a polyclonal antiserum and a monoclonal antibody

Summary We applied immunohistochemical procedures to detect hEGF in salivary glands and pleomorphic adenomas of salivary-gland origin using a polyclonal hEGF antiserum and a monoclonal antibody against hEGF synthesized by applying the synthetic gene technique using Escherichia coli. In normal salivary glands, hEGF was mainly localized in the ductal system (i.e., intercalated, striated, and excretory ducts). The staining intensity and intracellular localization exhibited some variation depending on the fixative used. When a polyclonal hEGF antiserum was used for immunostaining, slight background staining was observed in sections prepared using the fixatives tested. Therefore, precise localization of hEGF was obtainable only in formalin-fixed sections using the monoclonal antibody against hEGF. In pleomorphic adenomas, positive hEGF staining was seen on the luminal side of tumors and in cells of ductal origin; no reactivity was present on the outer side of tumors or in cells of myoepithelial origin. Occasionally, long, spindleshaped tumor cells and chondroidally changed tumor cells also exhibited positive staining for hEGF.     

Tissue distribution and immunoreactivity of heme-regulated eIF-2 alpha kinase determined by monoclonal antibodies.

A highly purified preparation of heme-regulated inhibitor (HRI), an eIF-2 alpha kinase, from rabbit reticulocyte lysates has been used for generating monoclonal antibodies (mAB). Two hybridoma clones secreting HRI-specific antibodies (mAB A and mAB F) were obtained. Both antibodies immunoprecipitated biosynthetically labeled as well as phosphorylated HRI in reticulocyte lysates and also recognized denatured HRI in a Western blot. In in vitro protein kinase assays, preincubation of HRI with the antibodies significantly diminished both autokinase and eIF-2 alpha kinase activities. HRI from reticulocyte lysates could be quantitatively removed by immunoprecipitation with mAB F, and such HRI-depleted lysates were able to maintain protein synthesis under conditions of heme deficiency. With these monoclonal antibodies, HRI was detected only in the reticulocytes and bone marrow of anemic rabbits, among several rabbit tissues tested. The antibodies did not detect cross-reacting HRI in rat or human reticulocytes or in mouse erythroleukemic cells or human K562 cells even after induction of differentiation, although eIF-2 alpha kinase activity was detected in them. Polyclonal anti-rabbit HRI antibody detected HRI in rat reticulocytes. However, no cross-reacting HRI was detected by polyclonal antibody in human reticulocytes or other cell types tested. These findings suggest that HRI is not ubiquitous, and may be erythroid-specific, and that it is antigenically different in different species.