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Biomedical subjects

G A Molinaro

Publications and source records attributed to G A Molinaro.

At least 19 recordsLinked to original sources
PubMed1992

Native epitopes of human IgA.

We have studied the epitopes of the human IgA molecule by using 27 monoclonal antibodies in two simple gel diffusion methods. By testing pairs of monoclonal antibodies for coprecipitation of an IgA myeloma protein, we have clearly identified sterically independent epitopes on the molecule. By testing the non-coprecipitating monoclonal antibodies with soluble IgA-monoclonal antibody immune complexes, we have identified the overlapping epitopes. Eleven proto-epitopes were mapped on the IgA molecule. Since we have not used solid-phase methods, we have presumably identified native epitopes of the IgA molecule.

Antibodies, Monoclonal↗
PubMed1989

Early ontogeny of rheumatoid factor antibodies. Characterization of a murine neonatal hybridoma autoantibody to IgGl in BALB/c mice.

The ontogeny and the function of rheumatoid factors (RF) are poorly understood. Here we describe a stable neonatal hybridoma cell line of BALB/c origin that secretes a RF autoantibody of the IgM class. By a series of in vitro assays we determined that this RF reacts specifically with the murine IgGl heavy chain. It also binds IgG of several mammalian species. By using mutant IgGl molecules, the reactive epitope was mapped to the CH3 domain of the constant region of IgGl. These findings indicate that clones with reactivity to autologous IgGl exist in normal mice at birth.

Animals↗
PubMed1988

Measuring human IgG4 by a two-site immunoradiometric assay with monoclonal antibodies.

By using 2 monoclonal antibodies, we developed a solid-phase 2-site immunoradiometric assay for measuring human IgG4. The measuring range (0.05-20 micrograms/ml) covered more than 2 orders of magnitude. The sensitivity level should make this assay especially useful when IgG4 concentrations are too low to be detected by conventional methods.

Antibodies, Monoclonal↗
PubMed1987

A monoclonal antibody may show cross-reactivities in Ouchterlony assays but not in other assays.

A monoclonal antibody to human IgG was tested with myeloma proteins of the four IgG subclasses. When tested by immunofluorometric assay, enzyme-linked immunosorbent assay, hemagglutination and hemagglutination inhibition assays, the antibody reacted with IgG3 but not with the other three IgG subclasses. When tested by Ouchterlony assays in the presence of polyethylene glycol, the antibody formed lines with all four IgG proteins. The line with IgG3 was sharp and stable, but the lines with the other three IgG subclasses tended to blur with time and with the lower PEG concentrations. These findings show that Ouchterlony assays can reveal cross-reactions of a monoclonal antibody that can be missed by more sensitive assays.

Antibodies, Anti-Idiotypic↗
PubMed1985

Monoclonal antibodies against squamous cell carcinoma.

We report on a monoclonal antibody reactive with squamous carcinoma cell lines and with frozen sections from squamous cell carcinomas of the oral cavity but not with frozen sections of normal squamous epithelium of the oral cavity, esophagus, and skin. In addition, we identified other monoclonal antibodies with restricted specificity as reflected by their binding to a panel of established tumor cell lines. Subsequent testing of these monoclonal antibodies against a panel of normal and tumor tissue sections revealed two types of reactivity patterns: binding to normal tissue and binding to normal and tumor tissue.

Animals↗
PubMed1984

One antigen may form two precipitin lines and two spurs when tested with two monoclonal antibodies by gel diffusion assays.

A monoclonal antibody reactive with human immunoglobulin (Ig)G4 and a monoclonal antibody reactive with IgG1, IgG2 and IgG4 were tested with an IgG4 myeloma protein by double diffusion in a polyethylene glycol-containing gel. In a three-well Ouchterlony pattern, the IgG4 myeloma protein formed lines of double partial identity (double spur) with the two monoclonal antibodies. The two spurs lengthened and thickened with decreasing concentrations of polyethylene glycol indicating that soluble immune complexes diffused past the precipitin lines and formed the spurs. In a two-well pattern, the myeloma protein formed two lines with mixtures of the two monoclonal antibodies indicating that the immune complexes formed by the two antibodies distributed bimodally in the gel as if two types of complexes were formed. These unpredicted findings indicate that the process of antigen-antibody precipitation in gels needs to be analyzed further by using monoclonal antibodies.

Animals↗
PubMed1984

Two monoclonal antibodies to two different epitopes of human growth hormone form a precipitin line when counterdiffused as soluble immune complexes.

We have tested whether soluble immune complexes obtained by mixing human growth hormone (hGH) with one anti-hGH monoclonal antibody (MAb) can form a precipitin line when diffused against another MAb in a polyethylene glycol containing gel. By testing seven anti-hGH MAbs one against the other in this assay, we have found that 10 pairs of MAbs out of the 21 possible combinations formed a line. Apparently, the first MAb formed soluble hGH dimers that were linked by the second MAb into precipitating linear complexes. Since each precipitin line was formed by the cooperative reaction of two MAbs, this sequential reaction of MAbs may be used in methods for the positive selection of MAbs that are suitable for two-site immunoassays.

Antibodies, Monoclonal↗
PubMed1981

Stimulation of human T lymphocytes by PHA-activated autologous T lymphocytes: analysis of the role of Ia-like antigens with monoclonal antibodies.

Human T lymphocytes activated with PHA express Ia-like antigens and acquire the ability to stimulate autologous T lymphocytes in mixed lymphocyte reaction. This reaction is immunological in nature since it has specificity and memory. Ia-like antigens play a role in the stimulation of T lymphocytes by autologous PHA-T lymphocytes since monoclonal antibodies to Ia-like antigens can significantly, although not completely, inhibit the stimulation.

Antibodies↗
PubMed1981

Cellular and molecular heterogeneity of H-2Kk antigens.

Up to 70% of mouse spleen cells expressing H-2Kk alloantigens reacted with the monoclonal anti-H-2Kk antibody 11-4.1 in an indirect rosetting assay. When the cells that rosetted with the monoclonal antibody 11-4.1 were removed by density centrifugation, the residual unreactive cells reacted with the polyclonal anti-H-2Kk alloantiserum D23 but not with the monoclonal antibody 11-4.1 indicating the existence of two cel populations. In sequential immunoprecipitation experiments, the glycoprotein fraction of NP40 extracts from H-2Kk cells, after removal of antigens reacting with the monoclonal antibody 11-4.1 still contained structures reactive with the alloantiserum. Therefore, there are at least two antigenically distinct H-2Kk molecules which are differentially expressed on two subpopulations of spleen cells.

Animals↗
PubMed1981

Analysis of human tumor cells for Ia-like antigens with monoclonal antibodies.

Cultured and noncultured human solid tumors were analyzed for expression of Ia-like antigens with the use of two monoclonal antibodies and a rabbit antiserum against human Ia-like antigens. Of 27 tumor cells tested, 3 melanomas bound antibodies [e.g., 21,563 cpm 131I-labeled staphylococcal protein A ([131I]SpA) with monoclonal antibody Q5/6], but 24 others (1 melanoma, 9 neuroblastomas, 1 medulloblastoma, 3 gliomas, 4 sarcomas, 2 colon carcinomas, 2 transitional cell carcinomas of the bladder, 1 teratoma, and 1 squamous cell carcinoma of the lung) did so minimally or not at all (0-427 cpm [131I]SpA with antibody Q5/6. Monoclonal antibody Q5/6 was quantitatively absorbed with homogenates of 32 noncultured tumors to determine if Ia-like antigens were expressed by neoplastic cells in vivo. Ten milligrams (wet wt) each of 5 of 7 noncultured melanomas removed more than 83% (median, 85%) of the antibody. In contrast, 10 mg each of 10 neuroblastomas, 7 carcinomas, 4 sarcomas, and 4 Wilms' tumors removed less than 47% (median, 19%) of the antibody; even 100 mg of these tumors removed less than 68% (median, 44%) of the antibody.

Antibodies↗