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Biomedical subjects

H G Kunkel

Publications and source records attributed to H G Kunkel.

At least 19 recordsLinked to original sources
PubMed1986

Dissection of the human antigammaglobulin idiotype system with monoclonal antibodies.

Murine monoclonal antibodies (MoAb) were prepared by immunizing mice with human monoclonal rheumatoid factors from patients with mixed cryoglobulinaemia. Indirect solid phase radioimmunoassay and haemagglutination inhibition were used to screen the MoAb. Reactivity patterns of MoAb were determined using (a) polyclonal and monoclonal IgM proteins, (b) monoclonal IgM proteins from patients with neuropathy, (c) monoclonal and polyclonal IgM antigammaglobulins, and (d) various isolated VkIIIb-positive immunoglobulins. Several patterns were obtained: MoAb reacting with private idiotypic determinants, with VkIIIb-related determinants, and with cross-reactive idiotypes (CRI). Two MoAb of the second type reacted with VkIIIb-positive immunoglobulins and light chains regardless of their antigenic activity. Another MoAb reacted with VkIII light chains only when in association with mu heavy chains. MoAb of the third type defined distinct CRI systems. One of these was restricted to antigammaglobulins and another also involved neuropathy-associated monoclonal IgM proteins. All MoAb clearly reacted with a minor population of normal polyclonal IgM, except for the MoAb detecting private idiotypic determinants. Studies using inhibition of binding by enzyme-linked immunosorbent assay showed that polyclonal IgM antigammaglobulins may carry a CRI determinant detected by one of the MoAb. This CRI system, defined by the MoAb Glo 86.3, was similar to but not identical with the previously described Wa CRI, which is widely prevalent among IgM antigammaglobulins of rheumatoid arthritis.

Animals↗
PubMed1985

Rapid generation of human T cell hybridomas.

Using the concept of a selectable surface marker we have generated screenable human T cell hybridomas within 4-7 days of fusion. OKT4+ T cell blasts were fused with MOLT4, an OKT4- T cell line, and OKT4+ fusion products were obtained by indirect rosetting technique. Supernatants of this heterogeneous population of hybrids were screened and those with activities of interest were subjected to cloning on soft agar and re-screening to dissect out various activities. Fusion efficiency, by staining, ranges from 6 to 80% depending on the state of activation of the T blasts and the growth phase of the MOLT4 line. This method allows for immortalization of T cell subpopulations, clones and malignant cells to study factor production and potentially messenger RNA for these factors. Additionally selectable surface markers may be used in human B cell and rodent:human fusions, avoiding the innate toxicity of various selection media.

Antigens, Surface↗
PubMed1985

Systemic lupus erythematosus with deficiency of the T4 epitope on T helper/inducer cells.

Three black Jamaicans with systemic lupus erythematosus (SLE) were identified whose T helper/inducer cells lacked the T4 epitope (T4 epitope-deficient phenotype). All three patients had lymphadenopathy as part of their syndromes. The asymptomatic and otherwise healthy T4 epitope-deficient brother of one of these patients also had lymphadenopathy in a distribution identical to that of his sister with SLE. Family studies pointed to an autosomal codominant mode of inheritance not linked to the HLA locus for the T4 epitope phenotype. Cultures of peripheral-blood mononuclear cells revealed impaired B-cell differentiation upon stimulation with pokeweed mitogen in cells originating from the T4 epitope-deficient family members as compared with those originating from their T4 epitope-intermediate relatives. Ratios of T helper/inducer cells to T suppressor/cytotoxic cells, the presence of various autoantibodies, and proliferation in response to mitogens and in the mixed lymphocyte reactions did not correlate with T4 epitope phenotype. We suggest that SLE in association with the T4 epitope-deficient phenotype may represent a unique subset of patients with SLE that has distinct clinical and immunologic properties.

B-Lymphocytes↗
PubMed1985

Human malignant T cells capable of inducing an immunoglobulin class switch.

Evidence is presented for the existence of a "switch" T cell derived from a patient with mycosis fungoides/Sezary's syndrome. The serum immunoglobulin profile in this patient revealed high IgG and IgA but no detectable IgM. Peripheral blood mononuclear cells from this patient secreted only IgG and IgA in the presence of pokeweed mitogen. T cells (Trac) co-cultured with normal allogeneic non-T cells and pokeweed mitogen resulted in only IgG and IgA PFC, with little or no IgM secretion. There was no evidence of active suppression of IgM. Rather, these T cells appeared to induce an Ig class switch from IgM to IgG and IgA, when co-cultured with mu+ tonsillar B cells. Further evidence was obtained using mononuclear cells derived from a patient with immunodeficiency and hyper-IgM, a syndrome characterized by a lack of IgG and IgA secretion. The addition of Trac cells to either peripheral blood mononuclear cells or non-T cells from a patient with hyper-IgM syndrome resulted in new secretion of IgG, with a concomitant decrease in IgM secretion, whereas control T cells were not effective in inducing secretion of any isotype other than IgM. Isolated Tac+ T cells from Trac appear to be responsible for this effect.

Antibody-Producing Cells↗
PubMed1985

Activated B lymphocytes: stimulators of an augmented autologous mixed leukocyte reaction.

The characteristics of the non-T cell(s) which stimulate T-lymphocyte proliferation in the autologous mixed leukocyte reaction (AMLR) have been at issue since this in vitro reaction was first described. Dendritic cells have been shown to be the most potent stimulator cells, but B cells, null cells, and macrophages have also been demonstrated to have the capacity to stimulate autologous T-cell proliferation. A cell preparation obtained from human peripheral blood was highly enriched for surface immunoglobulin-positive B cells. These cells were activated by brief culture with various B-cell mitogens and then compared to untreated B cells with regard to stimulatory activity in the AMLR. Mitogen-activated B cells were markedly augmented in their capacity to stimulate autologous T-cell proliferation when compared with untreated B cells. Fractionation of the B-cell preparation into high- and low-density subpopulations demonstrated that the high-density cells, enriched in resting B cells, had minimal stimulatory activity but could be activated to have increased AMLR-stimulatory capacity. Proliferation of the activated B lymphocytes was not required for the generation of the augmented AMLR. Response to both untreated and mitogen-activated B cells was a property of T4-positive T lymphocytes. The increase in stimulatory capacity was associated with a decrease in cell surface immunoglobulin, but no significant alteration in the percentage or fluorescence intensity of anti-Ia staining cells was detected. Activated B cells which are generated in vivo may acquire the capacity to generate T effector cells or factors important in the regulation of B-cell function.

Antibodies, Monoclonal↗
PubMed1985

A membrane protein preferentially expressed by a subpopulation of immature lymphoid cells, epidermal basal keratinocytes, and other epithelial cells.

A murine monoclonal antibody, designated EL-1, was raised by immunization with a human malignant T cell line. It reacted specifically with a membrane antigen expressed on T and B lymphoblastoid cell lines, a subpopulation of normal thymocytes and bone marrow lymphocytes, lymphocytes from a subset of patients with non-B, non-T cell acute lymphoblastic leukemia or T cell acute lymphoblastic leukemia and epithelial stem cells. The latter reactivity was especially striking in the skin, where only basal epidermal keratinocytes and epidermal appendages, including eccrine sweat glands, sebaceous glands and hair follicles, stained positively. A human epidermoid carcinoma cell line was also stained by EL-1. Suprabasilar keratinocytes and acellular keratin did not stain. However, in vitro proliferating fetal lung fibroblasts stained positively. Membrane immunoprecipitation analysis demonstrated that the antigen recognized by antibody EL-1 is a single protein of molecular weight 105 kilodaltons which did not change with exhaustive chemical reduction. Metabolic radiolabeling studies demonstrated that this protein is synthesized by the cell and not merely taken up from the culture medium. This antibody can be useful in studying keratinocyte differentiation in epidermal malignancies and normal skin.

Animals↗
PubMed1985

Autoimmune sera reactive with Sm antigen contain high levels of RNP-like antibodies.

Ribonucleoprotein particles containing Sm antigen were separated from particles containing both Sm and RNP antigens by ion-exchange chromatography to study the recognition of these antigens by autoimmune sera. By using the separated antigens, anti-Sm and/or anti-RNP antibodies were detected in approximately 60% of sera from systemic lupus erythematosus patients by both enzyme-linked immunosorbent assay and immunoprecipitation of radiolabeled antigens followed by analysis on sodium dodecyl sulfate-polyacrylamide gels. These antibodies were detected in 30% of the same sera using the standard passive hemagglutination technique. Competition experiments demonstrated that all of the sera tested that contained anti-Sm antibodies also had anti-RNP-like reactivity. This latter reactivity usually represented 80% or more of the total Sm and RNP binding activity in lupus sera. The binding to RNP-like determinants by several of the sera was uniquely resistant to treatment of the antigen with snake venom exonuclease. These studies indicate that humoral immunity against Sm and RNP antigens in systemic lupus erythematosus is directed primarily against a single type of ribonucleoprotein particle in which the two antigens are physically associated. The specific binding to a single type of ribonucleoprotein particle suggests that this particle may be especially immunogenic and that it might play an important role in induction of the humoral immune response to Sm and RNP.

Antigens↗
PubMed1984

T cell antiidiotypic antibodies reveal differences between two human leukemias.

Two different human T cell leukemias were compared, using antiidiotype-like murine monoclonal antibodies. In each case these antibodies immunoprecipitated disulfide-linked heterodimer molecules from their respective leukemic cells. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the two idiotype-bearing molecules a major difference in molecular weight was observed, which could be attributed to a similar difference in size of the heavily iodinated chain of either heterodimer. The lightly iodinated chains of both molecules co-migrated at 43 Kd, but appeared to have different isoelectric points on two-dimensional gel analysis. The possibility that these two different heterodimers correspond to different classes of the putative T cell receptor for antigen is discussed. Assays of proliferation of the leukemic cells using Sepharose-bound antiidiotype-like monoclonal antibody showed that one of the leukemic cell types proliferated readily in response to its antiidiotypic antibody. This proliferation was not associated with measurable production of IL-2 and appeared to be a direct effect of the antiidiotypic antibody, which may mimic antigen in its interaction with the T cell receptor for antigen. The other leukemic cell type did not respond to Sepharose-bound antiidiotypic antibody and was generally unresponsive to lymphokines and mitogens. It is possible that the two leukemic cell types represent different stages of T cell differentiation.

Animals↗
PubMed1984

Anti-immunoglobulin antibodies IV. Cross-reaction of anti-idiotypic antibodies specific for rabbit and murine anti-a1 allotype antibodies with Fc fragment of human immunoglobulins.

Anti-idiotype (Id) antibodies against anti-a1 rabbit allotype antibodies were produced in rabbits and mice by immunization with polyclonal rabbit anti-a1 allotype or with a monoclonal murine anti-a1 allotype antibody, respectively. These antibodies recognize an interspecies cross-reactive idiotope on anti-a1 allotype antibodies. However, these anti-Id antibodies also react with various subclasses of human IgG. In multiple systems, it was shown that these anti-Id antibodies interact with the Fc fragment of human IgG and, therefore, exhibit a rheumatoid factor-like activity. These results support the hypothesis that gamma-globulin may not be the only stimulus to clones producing rheumatoid factors and that perhaps other antibodies, especially anti-Id antibodies, also bind gamma-globulin secondarily.

Animals↗
PubMed1984

Idiotype expression in rheumatoid synovial plasma cells.

The majority of the polyclonal plasma cells identified in the synovial tissues of rheumatoid arthritis patients contain immunoglobulins that express a common idiotype related to that of the monoclonal cryoglobulins of the Wa group (RCRI). In these same tissues, there are twice as many plasma cells which are marked by a common idiotype yet do not show binding of aggregated IgG. These plasma cells are members of an idiotypically parallel set relative to those which produce rheumatoid factor. Direct comparison of rabbit polyclonal RCRI+ plasma cells with murine monoclonal RCRI+ plasma cells using two color fluorescent counterstains shows that the epitope recognized by the monoclonal anti-RCRI exists among a set of epitopes present in the RCRI. Since all the monoclonal RCRI+ plasma cells are not also positive with the polyclonal anti-RCRI antisera, the epitope characterized by the monoclonal antibody Glo 86.3 is not included among the set of epitopes the polyclonal antiserum identifies. A suitably absorbed anti-idiotypic polyclonal antiserum is superior to monoclonal antibodies for the purpose of detection of molecules (and cells) that are part of a polyclonal reaction involved in a given immune response.

Antibodies, Monoclonal↗
PubMed1984

Pulse labeling of small nuclear ribonucleoproteins in vivo reveals distinct patterns of antigen recognition by human autoimmune antibodies.

Antibodies directed against small nuclear ribonucleoprotein ( snRNP ) particles are found in the Sm and RNP autoimmune sera from numerous patients with systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). These two reactivities differ in disease distribution as well as antigen specificity. Although sera from both of these autoimmune syndromes contain snRNP reactive antibodies, distinction in antigen binding specificity have been difficult to define because of the particulate nature of the snRNP antigen. To overcome this problem, while retaining the antigen in a native state, cells were pulse-labeled with [35S]methionine for 8 min to generate radioactive snRNP proteins in forms reflecting incomplete de novo particle assembly. Immunoprecipitation of snRNP antigen prepared in this manner revealed clearly distinct patterns of Sm and RNP immunorecognition . While Sm sera precipitated all eight labeled snRNP proteins, RNP antibodies precipitated only two of the eight. However, a brief pulse followed by periods of cold chase demonstrated that RNP sera can eventually coprecipitate all components of the complete particle. In addition to antibodies to the other six snRNP peptides, all Sm sera tested have been found to contain the RNP-like reactivity with snRNP proteins A and C. RNP reactivity with these two components is of particular interest because these proteins are unique in the metabolism of snRNPs. Defining and distinguishing the precise peptides recognized by Sm and RNP antibodies has helped to clarify the biochemical basis of the standard laboratory tests for these antigen reactivities.

Antigen-Antibody Complex↗
PubMed1984

Heterogeneity in expression of the T4 epitope in black individuals.

The T-cell differentiation antigen T4/Leu3 has been described as a non-polymorphic molecule important in T-cell recognition of class II major histocompatibility complex antigens. We report the polymorphism of this molecule in black individuals as manifest by a heterogeneity of staining with OKT4 monoclonal antibody. No such heterogeneity was observed when staining with other monoclonal antibodies that bind to different epitopes of the same molecule. No heterogeneity of staining with any of the monoclonal antibodies was observed in whites. Three patterns of OKT4 staining emerged: intact, deficient, and intermediate. This heterogeneity is likely to be due to an intrinsic heterogeneity in T4 epitope expression and not secondary to an interfering plasma factor as shown by the preservation of the T4 epitope pattern after a 3-day culture in the presence or absence of mitogen. Family studies strongly suggest that this heterogeneity in T4 epitope expression is inherited in an autosomal codominant fashion.

Africa↗
PubMed1984

Regulation of B cell activation and differentiation with factors generated by human T cell hybridomas.

Human T cell hybridomas were generated by several techniques and the supernatants generated were screened for activity on human B cells. Three general activities were noted; B cell proliferation factor ( BCPF ), B cell differentiation factor (BCDF), and an IgA isotype-specific helper factor. BCPF acts on B cells to induce proliferation without differentiation and is distinct from conventional BCGF. This was documented by BCPF 's inability to synergize with anti-mu Ab in a standard BCGF assay ( Muraguchi & Fauci 1982, Howard et al. 1982, Sieckman et al. 1981), as well as its differential effect on a leukemic B cell preparation, when compared with BCGF. A possible schema for BCPF activity is depicted in Figures 3 and 4. In Figure 3, BCPF acts like Ag in vivo or like anti-mu in vitro, pre-activating B cells and rendering them responsive to BCGF. Figure 4 represents what our data depict, that is that BCPF bypasses the response to BCGF and induces cells to proliferate without pre-activation. The difference in the 2 mechanisms may be concentration-dependent and this possibility is currently being evaluated. It is interesting to speculate that T cells in vivo are capable of initiating B cell activation and may account for polyclonal responses seen with some Ag-specific reactions. BCDF(s) act on post-activated B cells (Figure 3) to induce differentiation to Ig-secreting cells. They appear to be heterogeneous and, therefore are capable of inducing varied responses depending on the B cell subpopulation affected. Figure 3 is deliberately complex demonstrating some of the possible as well as documented BCDF activities including polyclonal differentiation and isotype specific activity in IgA committed B cells. We cannot be certain of the frequency of these BCDF-secreting T cells, but the studies of cells from patients with common variable immunodeficiency and chronic lymphocytic leukemia have helped to dissect out these activities. These data would suggest that these BCDF subgroups are important, as deficiencies in one or more subgroups may result in disease.

Antibodies, Anti-Idiotypic↗
PubMed1984

Soluble factors inhibitory for T-cell-dependent immune responses in patients with the acquired immune deficiency syndrome and its prodromes.

Supernatants from PBMC obtained from certain patients with AIDS or its prodrome were capable of depressing pokeweed mitogen-driven immunoglobulin production and the proliferative response of T cells to specific antigen. These soluble suppressor factors (SSF) were present in uniquely high concentrations, and were the product of an interaction of T lymphocytes with adherent cells. T-cell independent functions were not modified by soluble suppressor factors. Restoration of immunoglobulin synthesis in SSF-treated cultures was realized by addition of reducing agents such as 2-mercaptoethanol, suggesting inhibitory mechanisms possibly related to that of Con A-induced soluble immune response suppression, and perhaps offering clues to clinically applicable substances capable of modifying such responses. A relationship between SSF-AIDS and a human retrovirus LAV/HTLV III, linked etiologically to AIDS and its prodromes, is suggested by studies of SSF-like substances released by human T-T cell hybridomas derived from LAV+ patients.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Polyclonal immunoglobulin secretion in patients with common variable immunodeficiency using monoclonal B cell differentiation factors.

B cells from 25 patients with common variable immunodeficiency (CVI) were tested for their ability to differentiate under the influence of B cell differentiation factors (BCDF), derived from T cell hybridomas or T cell clones. 11 patients generated Ig plaque-forming cells in the range comparable to that of normal controls with supernatant from the T cell hybrid MOP 1L. With various hybrid or clone supernatants, differing response patterns emerged. Four patients who failed to respond to MOP 1L responded to T cell clone supernatant RAC. Another who failed to respond to both MOP 1L and RAC responded to T cell hybrid supernatant MTP 7. These results indicate that these supernatants contain different BCDFs and suggest heterogeneity in the differentiation states of B cells in CVI. In addition, three patients demonstrated exaggerated responses to BCDF, and evidence was obtained from B cells of these patients for increased BCDF receptor density. Thus, the accumulated evidence indicates that T cell defects may be a primary pathogenetic mechanism in common variable immunodeficiency, and purified BCDF may be of therapeutic value.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1984

An antigen characteristic of hairy cell leukemia cells is expressed on certain activated B cells.

A murine monoclonal antibody, anti-HC2, which reacts with hairy cell leukemia cells, was used to define the normal cell equivalent for the leukemic hairy cell. This antibody stained the membranes of 2.24% of normal peripheral blood lymphocytes. These cells were more common in T cell-depleted cell populations, and bore membrane immunoglobulin. Some B lymphoblastoid cell lines were also anti-HC2-positive. Examination of normal B cell subpopulations revealed that HC2-positive cells frequently co-express an activation antigen and membrane IgG. Cell populations enriched for HC2-positive cells contained the bulk of PWM-responsive B cells. These data suggest that HC2-bearing B cells are activated B cells. B cell differentiation induced in vitro by PWM with T cell helper factors resulted in an increase in the number of HC2-positive cells at day 4 or 5 of culture. The HC2-positive cells were no longer present at the time of maximal plasma cell differentiation on day 7 of culture. By using B cells from a patient with the hyper-IgM syndrome that are incapable of immunoglobulin heavy chain class switching, it was demonstrated that HC2 expression did not require prior heavy chain switch. The m.w. of the HC2 antigen was 52 to 63 KD. Four bands with different isoelectric points were discerned on two-dimensional analysis. We suggest that hairy cell leukemia represents a malignancy of activated B cells. A unique stage of B cell differentiation is identified by the HC2 activation antigen.

Antibodies, Monoclonal↗
PubMed1984

A membrane antigen (HC1) selectively present on hairy cell leukemia cells, endothelial cells, and epidermal basal cells.

A monoclonal antibody (alpha HC1) raised against HCL cells reacted specifically with HCL cells and not with other normal or leukemic B cell types. It also reacted with BC and with vascular EC. One case of Kaposi's sarcoma, a tumor thought to derive from EC, was also stained by this antibody. Sinusoidal cells of liver and spleen and EC in the brain did not stain with alpha HC1, but EC from all other tissues and EC in culture were positive. Because the exact normal cell equivalent of the leukemic hairy cell is unknown, similarities in phenotype and function between EC and hairy cells are of particular interest.

Antibodies, Monoclonal↗