Molecular and genetic immunoprobes for biotechnology

Recent advances concerning immunoprobes are described and their biotechnologic potential is emphasized. Selected examples of immunoprobes discussed include interleukin 7, genetically engineered vaccines using live bacterial carriers, and applications of monoclonal antibodies (MAb's) for understanding and controlling blood cell malignancies as well as for analysis of prokaryotic cells. The fundamental and practical interconnections of these research areas are highlighted to show, for instance, that definition of lymphoid-cell lineages and identification of their various subsets are aided by MAb's and interleukins. On the other hand, understanding interleukins requires isolation of cell subsets. Likewise, designing vaccines presupposes a knowledge of lymphocyte subsets and of the antigenic mosaics of the pathogens against which the vaccines are directed. Dissection of antigens in cells and in infectious agents depends to a great extent on MAb's, which are also instrumental for cloning the genes encoding antigens for vaccine preparation and those encoding interleukins for large scale production of these molecules that are promising as immunotherapeutic and vaccine adjuvants. Last, brief mention is made of the uses of MAb's in prokaryotic cell biology to illustrate the long-range impact on these immunoprobes and, consequently, how they are opening new avenues for biotechnology.

Methanocorpusculaceae fam. nov., represented by Methanocorpusculum parvum, Methanocorpusculum sinense spec. nov. and Methanocorpusculum bavaricum spec. nov

Two new methanogenic bacteria, Methanocorpusculum sinense spec. nov. strain DSM 4274 from a pilot plant for treatment of distillery wastewater in Chengdu (Province Sichuan, China), and Methanocorpusculum bavaricum spec. nov. strain DSM 4179, from a wastewater pond of the sugar factory in Regensburg (Bavaria, FRG) are described. Methanocorpusculum strains are weakly motile and form irregularly coccoid cells, about 1 micron in diameter. The cell envelope consists of a cytoplasmic membrane and a S-layer, composed of hexagonally arranged glycoprotein subunits with molecular weights of 90,000 (Methanocorpusculum parvum), 92,000 (M. sinense), and 94,000 (M. bavaricum). The center-to-center spacings are 14.3 nm, 15.8 nm and 16.0 nm, respectively. Optimal growth of strains is obtained in the mesophilic temperature range and at a pH around 7. Methane is produced from H2/CO2, formate, 2-propanol/CO2 and 2-butanol/CO2 by M. parvum and M. bavaricum, whereas M. sinense can only utilize H2/CO2 and formate. Growth of M. sinense and M. bavaricum is dependent on the presence of clarified rumen fluid. The G + C content of the DNA of the three strains is ranging from 47.7-53.6 mol% as determined by different methods. A similar, but distinct polar lipid pattern indicates a close relationship between the three Methanocorpusculum species. The polyamine patterns of M. parvum, M. sinense and M. bavaricum are similar, but distinct from those of other methanogens and are characterized by a high concentration of the otherwise rare 1,3-diaminopropane. Quantitative comparison of the antigenic fingerprint of members of Methanocorpusculum revealed no antigenic relationship with any one of the reference methanogens tested. On the basis of the distant phylogenetic position of M. parvum and the data presented in this paper a new family, the Methanocorpusculaceae fam. nov., is defined.

Isolation and Characterization of Methanogenic Bacteria from Landfills

Methanogenic bacteria were isolated from landfill sites in the United Kingdom. Strains of Methanobacterium formicicum, Methanosarcina barkeri , several different immunotypes of Methanobacterium bryantii , and a coccoid methanogen distinct from the reference immunotypes were identified.

Methanogenic bacteria from human dental plaque

Samples of human dental plaque were examined for the presence of methanogenic bacteria. Of 54 samples from 36 patients, 20 yielded H2/CO2-using methanogenic enrichment cultures. All methanogen-positive samples were from patients with some degree of periodontal disease. The predominant populations in the enrichments had morphologies characteristic of Methanobrevibacter spp. In six enrichments derived from three patients, the common methanogen was antigenically similar to Methanobrevibacter smithii. The same was true for the three methanogenic isolates obtained in axenic culture from a fourth patient. The six enrichments and two of the three isolates were antigenically closer to strain ALI than to PS. Two of the enrichments also had subpopulations with weak antigenic similarity to Methanosphaera stadtmanae. The data indicate that methanogens in the oral cavity of humans are antigenically close to those found in the intestinal tract.

Monoclonal antibodies against bacteria

Highlights are presented of most recent work in which monoclonal antibodies have been instrumental in the study of bacteria and their products. Topics summarized pertain to human and veterinary medicines, dentistry, phytopathology, ichthyology, and bacterial ecophysiology, differentiation, evolution and methanogenic biotechnology.

Slide immunoenzymatic assay (SIA): improving sensitivity to measure antibodies when samples are very small and dilute, and antigen is scarce

Modifications to the slide immunoenzymatic assay (SIA) using the PAP reagent (SIA-PAP) were developed which increase sensitivity considerably. These SIA modifications are particularly useful for measuring speedily antibodies in dilute samples available only in microliter-volumes when antigen is scarce, whether a molecule, or a prokaryotic or eukaryotic cell.

Antigenic distinctiveness, heterogeneity, and relationships of Methanothrix spp

A detailed immunologic analysis of Methanothrix soehngenii Opfikon (the type species of the genus), Methanothrix sp. strain CALS-1, and Methanothrix concilii GP6 was performed. A variety of poly- and monoclonal antibody probes for a comprehensive panel of reference organisms were used to determine immunogenicity, antigenicity, and relationships. The three organisms are antigenically distinct but interrelated, forming an immunologically cohesive group, weakly related to methanosarcinae. A prominent feature of the organisms was heterogeneity characterized by antigenic diversity and compartmentation, the latter particularly evident in M. soehngenii Opfikon, which was examined more thoroughly. The complexity of the antigenic profile of this strain and the heterogeneity of the group suggest a high degree of phenotypic diversification within the genus.

Multiple solid-phase system for storage of dry ready-for-use reagents and efficient performance of immunoenzymatic and other assays

A modular system of independent but matching solid phases coated with the reagents for the slide immunoenzymatic assay (SIA) was developed. Antigen, antiserum, second antibody labeled with enzyme, and substrate are immobilized as dry films onto circles surrounded by a hydrophobic material on separate glass slides. The reagents stay on the circles ready for use for at least 1 year. Circles coated with the two reagents involved in each step of the assay are approximated to one another by pairing slides, one on top of the other. Hinged slide frames ensure exact superposition of circles with matching reagents separated by a gap 1 mm thick. This is occupied by a liquid column that forms from a 10 microliters drop of water or buffer pre-deposited onto the circles of the bottom slide. The liquid bridge provides the milieu for interaction of reagents. Pairs of slides are incubated as needed for each step. The enzymatic reaction of the last step is read with a vertical beam spectrophotometer. The same multiple-phase system can be used for immunofluorescence. Reactions occur faster using the system than when reagents are admixed in solution.

Antigenic mosaic of Methanogenium spp.: analysis with poly- and monoclonal antibody probes

Eight well-characterized Methanogenium strains, including the six described type strains, were analyzed with poly- and monoclonal antibody probes to examine the antigenic mosaic of the genus. The pattern of cross-reactions showed that the mosaic is complex and varies with the strains; thus, these organisms have developed a considerable antigenic diversity, which is expressed in their envelopes. Every strain shared at least one determinant with at least one other strain, demonstrating the antigenic cohesiveness of the group. This finding, together with the fact that most strains displayed a distinctive antigenic fingerprint (notwithstanding the limited number of probes available), emphasizes the potential of antibodies for rapid identification of new isolates and for direct elucidation of Methanogenium strains in microbial mixtures.

Immunologic distinctiveness of archaebacteria that grow in high salt

The antigenic fingerprints of eight halophilic archaebacteria representing the groups recently outlined by molecular and chemical analyses were determined with calibrated antibody probes. Comparison with the antigenic fingerprints of methanogens encompassing all described families and most genera demonstrated that these two archaebacterial groups are themselves antigenically coherent but immunologically distinct.

Slide immunoenzymatic assay for human IgE (SIA-IgE)

A rapid and inexpensive method is described for determination of human serum IgE using 5-microliter samples. The slide immunoenzymatic assay for IgE (SIA-IgE) is carried out on a glass slide in which up to 24 samples can be tested including controls and standards; up to four of these slides can be read automatically in conventional vertical beam readers. Flat circles on the slide are covered with a layer of biotinylated antibody specific for human IgE (trapping antibody). Five microliters of serum sample is dropped to cover each circle, and the slide is incubated. The circles are washed with water, dried, incubated under 10 microliters of enzyme-labeled antibody to human IgE, then washed again, and covered with 10 microliters of enzyme substrate. The intensity of color generated is measured at the proper wavelength. The method is simple, accurate and non-radioactive and can be completed within 2 h.

Monoclonal antibodies for bacterial identification and taxonomy: 1985 and beyond

Contemporary bacterial serology relevant to medicine involves poly- and monoclonal antibodies to study pathogenic bacteria and nonpathogenic organisms useful in controlling infectious diseases. Monoclonal antibody applications include immunodiagnostics, prophylaxis and serotherapy, and microbial biotechnology and molecular immunochemistry. If used in parallel with antisera, the analytic potential of monoclonal antibodies is better realized. However, the entire range of advantages from the use of monoclonal antibodies can only be attained if the antibodies are well characterized.

Slide immunoenzymatic assay for immunoglobulin isotype (SIA-Ig)

A simple method is described for rapid determination of immunoglobulin class and subclass in an assortment of samples based on the slide immunoenzymatic assay (SIA-Ig). Each circle on a multi-circle glass slide is coated with anti-immunoglobulin class or subclass antibody. For each isotype to be assayed a circle is coated with its specific anti-isotype. The coated circles are incubated with sample containing the immunoglobulin(s) of unknown isotype and are then washed. The slide is then incubated with enzyme-labeled anti-immunoglobulin and washed again. Finally, enzyme substrate is deposited onto the circles. Color appears within a few minutes only on the circle where the unknown was bound specifically by its corresponding anti-isotype antibody. The method reveals correctly the isotype of the constituents of complex mixtures, such as serum, as well as that of the only component of samples containing a single molecular species of immunoglobulin (e.g., monoclonal antibodies). The method is simple, reliable, gives results in less than 1 h and is adequately sensitive for a wide range of practical applications.

Six antigenic determinants in the surface layer of the archaebacterium Methanococcus vannielii revealed by monoclonal antibodies

The immunogenicity and antigenic characteristics of the unique surface layer (S layer) of Methanococcus vanielii was studied with a panel of six monoclonal antibodies. Six surface determinants were identified for the first time, each recognized by one antibody exclusively. The determinants are proteins, located in the S layer, and accessible to antibody in whole, unfixed, as well as formalinized bacteria. Hence the six antigens and antibodies reported here should be useful for rapid identification of new isolates and for taxonomy of methanogens, notably Methanococcaceae. In this connection two novel applications of the slide immunoenzymatic assay were developed for analyses of monoclonal antibodies and their complementary sites in the bacterial envelope.

Six antigenic determinants in the surface layer of the archaebacterium Methanococcus vannielii revealed by monoclonal antibodies

The immunogenicity and antigenic characteristics of the unique surface layer (S layer) of Methanococcus vanielii was studied with a panel of six monoclonal antibodies. Six surface determinants were identified for the first time, each recognized by one antibody exclusively. The determinants are proteins, located in the S layer, and accessible to antibody in whole, unfixed, as well as formalinized bacteria. Hence the six antigens and antibodies reported here should be useful for rapid identification of new isolates and for taxonomy of methanogens, notably Methanococcaceae. In this connection two novel applications of the slide immunoenzymatic assay were developed for analyses of monoclonal antibodies and their complementary sites in the bacterial envelope.

Antibacterial monoclonal antibodies and the dawn of a new era in the control of infection

Literature reports concerned with monoclonal antibodies against bacteria, or their toxins, which are pathogens for man and animals were surveyed. These antibodies have important potential uses in human and veterinary pathology and medicine. They are likely to become key elements in a fast progression toward a more complete understanding and control of infectious diseases and of toxin poisoning. A new area of bacteriology relevant to sanitary engineering is also being advanced with the help of antibacterial monoclonal antibodies. This area involves bacteria that produce the biofuel methane, along with other molecules of nutritional value, through a process which brings about the recycling of organic wastes and thereby limits or controls microbial contamination of soil and water.

Dissecting the antigenic mosaic of the Archaebacterium Methanobacterium thermoautotrophicum by monoclonal antibodies of defined molecular specificity

The antigenic mosaic of the Archaebacterium Methanobacterium thermoautotrophicum, strain delta H, was analyzed with a panel of six monoclonal antibodies. Five antigenic determinants were identified. One contains N-acetyl-D-glucosamine, another contains N-acetyl-D-galactosamine, and a third contains gamma-glutamylalanine (gamma-Glu-Ala). These residues are not involved, at least as immunodominant epitopes, in the other two determinants, one of which contains L-talosaminuronic acid, a component of pseudomurein found only in Methanobacteriaceae. Each of the five determinants was recognized by one monoclonal antibody exclusively. A sixth antibody recognized a structure containing gamma-Glu-Ala that could be either a sixth determinant or a subdeterminant within the site already recognized as containing gamma-Glu-Ala. We postulate that two of the determinants are strain specific, three are species specific, and one is a common antigen.

Quantitative slide micro-immunoenzymatic assay (micro-SIA) for antibodies to particulate and non-particulate antigens

A quantitative, minimized version of the slide immunoenzymatic assay (SIA) is described, which is performed with a 5 microliters drop of each reagent on a circular glass surface (3 mm in diameter) delimited by a thin layer of a hydrophobic material. Measurements are done directly, without disturbing the drop of substrate solution while the enzymatic reaction takes place, by means of a vertical beam spectrophotometer. The main features of this quantitative micro-SIA are its simplicity, reproducibility, virtual absence of background and applicability to a large variety of antigen-antibody systems.

Antigenic analysis of Methanomicrobiales and Methanobrevibacter arboriphilus

Preparation of new antisera has permitted more comprehensive immunological analyses of the two families of Methanomicrobiales. Methanomicrobiaceae and Methanosarcinaceae, and the species Methanobrevibacter arboriphilus. Immunological analysis was carried out with antibody probes against 23 strains, including almost all genera and species of methanogens. The absence of cross-reactions between families of methanogens was confirmed. Methanomicrobium and Methanogenium were found to be immunologically related. Extensive cross-reactions occurred among six strains of Methanosarcinaceae, but none occurred among three strains of M. arboriphilus when tested with the S probe, i.e., the last antiserum dilution of the titration curve's plateau.

Monoclonal antibodies for immunochemical analysis of methanogenic bacteria

Sixty-nine hybridomas were generated to produce monoclonal antibodies to species of methanogens representing three of the four families accepted at the present time: Methanobacteriaceae, Methanococcaceae, and Methanomicrobiaceae. The antibody of each of 29 hybridomas cross-reacted with a methanogen of the same species or genus as the immunizing (homologous) strain, whereas the antibody of the other 40 cell lines reacted only with the homologous strain. Inhibition-blocking experiments with compounds of known composition and structure were used to define the fine specificity of antibodies of four hybridomas representing the four genera of the methanogens used for immunization. The combining site of the monoclonal antibody against M. thermoautotrophicum delta H examined is specific for a structure in the pseudomurein involving N-acetyl-glucosamine but not the (1-3) linkage or the C-terminus gamma-Glu-Ala of the peptide, both of which are characteristic of pseudomurein, the cell-wall peptidoglycan distinctive of the Methanobacteriaceae. In contrast, the monoclonal antibody to the other methanogen of this family examined, M. arboriphilus DH1, recognizes a determinant involving gamma-Glu-Ala. Thus pseudomurein expresses at least two dissimilar antigenic determinants in different portions of the molecule. The monoclonal antibodies against M. vannielii SB and M. hungatei JF1, whose families do not possess pseudomurein, did not display specificity for analogues of pseudomurein.

Monoclonal antibodies for immunochemical analysis of methanogenic bacteria

Sixty-nine hybridomas were generated to produce monoclonal antibodies to species of methanogens representing three of the four families accepted at the present time: Methanobacteriaceae, Methanococcaceae, and Methanomicrobiaceae. The antibody of each of 29 hybridomas cross-reacted with a methanogen of the same species or genus as the immunizing (homologous) strain, whereas the antibody of the other 40 cell lines reacted only with the homologous strain. Inhibition-blocking experiments with compounds of known composition and structure were used to define the fine specificity of antibodies of four hybridomas representing the four genera of the methanogens used for immunization. The combining site of the monoclonal antibody against M. thermoautotrophicum delta H examined is specific for a structure in the pseudomurein involving N-acetyl-glucosamine but not the (1-3) linkage or the C-terminus gamma-Glu-Ala of the peptide, both of which are characteristic of pseudomurein, the cell-wall peptidoglycan distinctive of the Methanobacteriaceae. In contrast, the monoclonal antibody to the other methanogen of this family examined, M. arboriphilus DH1, recognizes a determinant involving gamma-Glu-Ala. Thus pseudomurein expresses at least two dissimilar antigenic determinants in different portions of the molecule. The monoclonal antibodies against M. vannielii SB and M. hungatei JF1, whose families do not possess pseudomurein, did not display specificity for analogues of pseudomurein.