Studies of the expression of the Wiskott-Aldrich syndrome protein.

The Wiskott-Aldrich syndrome (WAS) is an X-linked disorder characterized by thrombocytopenia, eczema, disorders in cell-mediated and humoral immunity, and a proclivity to lymphoproliferative disease. The gene responsible encodes a 53-kD proline-rich protein of unknown function (WASP). We produced a FLAG-WASP fusion protein that was used to immunize mice and produce mAbs against WASP. Using monoclonal anti-WASP in Western immunoblots, we have determined that WASP is present in the cytoplasmic but not nuclear fraction of normal human peripheral blood mononuclear cells, in normal human platelets, in T lymphocytes, non-T lymphocytes, and monocytes. The protein is produced in the B cell immunoblastic cell line DS-1, in normal EBV-transformed B cell lines, and in HEL92.1.7, but is barely detectable in MOLT-4 and not detectable in K562. WASP was present in two of four EBV-transformed cell lines from WAS patients. Splenic tissue immunostaining was performed in two patients, and the results correlated with the results of the Western blots. Sequence analysis of WASP cDNA from two patients who produce WASP show mutations causing amino acid substitutions. These studies establish a foundation for further studies aimed at understanding the function of WASP.

Nitrosamine-induced transplantable pancreatic ductal adenocarcinoma in inbred Syrian hamsters.

A pancreatic ductal carcinoma, designated CBP, was established as a transplantable tumor line in the CB/SsLak inbred strain of Syrian golden hamsters. The tumor, a primary one induced by chronic administration of the nitrosamine N-nitro-bis(2-hydroxyproyl) amine, is a well-differentiated adenocarcinoma that can be propagated by transplantation in syngeneic hamsters. It grows poorly in other hamster strains. The CBP tumor develops in a predictable quantitative manner and metastasizes to regional lymph nodes. Excision of primary transplanted tumor nodules leads to immunity against subsequent secondary tumor challenges. The CBP tumor appears to be a suitable model for biologic and immunologic studies of pancreatic carcinoma in the syrian hamster.

Active immunization of hamsters against pancreatic carcinoma with lipid-treated cells or their shed antigens.

Increasing membrane lipid microviscosity of cells by treatment with cholesterol esters such as cholesterol hemisuccinate (CHS) enhances immunogenicity, probably by exposure of cryptic membrane antigens. Transplantable pancreatic carcinoma lines CBP and LSP-1 grown in inbred hamsters were tested for immunogenicity after CHS treatment. Tumor cells were incubated in CHS to rigidify cell membranes, and they were irradiated and injected i.p. into syngeneic hamsters. Incubation media after CHS treatment, considered to contain shed antigens due to hyperrigidification, were also used for immunization. Two identical immunizations using 10(7) cells or incubation media were performed 14 days apart. In control experiments, non-CHS-treated, irradiated cells were injected. Immunizations were performed using both syngeneic and allogeneic cells and supernatants for both the CBP and LSP-1 systems for specificity experiments. The degree of immunization in the treated hamsters was assessed by the response to a subsequent s.c. challenge with viable tumor cells given 7 days following the last immunization. For the CBP pancreatic cancer line, CHS treatment increased tumor immunogenicity significantly, as demonstrated by diminished tumor growth rate and by increased duration of survival after challenge. With the LSP-1 pancreatic tumor, immunization with CHS-treated cells showed no enhancement of immunogenicity. However, immunization with supernatant of CHS-treated cells resulted in a significant delay of tumor growth and increased survival, suggesting immunization by shed antigens in the CHS incubation medium. Use of CHS-treated cells or shed antigeneic material could be of potential value as a method of active immunotherapy.

Demonstration of type-R and type-C virus particles in hamster pancreatic adenocarcinomas.

Two transplantable solid tumors (CBP and PDP) and two continuous cultured cell lines (CBP-TC and PDP-TC) were established from nitrosamine-induced pancreatic ductal adenocarcinomas in inbred Syrian hamsters. Electron microscopic examination of both CBP and PDP solid tumors as well as CBP-TC cultured cells revealed the presence of type-R virus particles, which consisted of a 100 nm envelope containing a central 50 nm nucleoid with characteristic radiating 'spokes'. Type-R particles were abundant in cultured CBP-TC cells, moderately frequent in CBP solid tumors, and rare in PDP solid tumors; they were not present in PDP-TC cultured cells. The CBP and PDP solid tumors and cultured PDP-TC cells exhibited type-C viral particles, having a 150 nm envelope containing a 75 nm nucleoid. Mature, immature and budding forms of Type-C viruses were present and quite prominent in PDP tumors. Type-C particles were present but rare in CBP solid tumors and in PDP-TC cells. C-particles were not observed in cultured CBP-TC cells. Examination of normal hamster pancreas, liver, duodenum, muscle and connective tissue failed to reveal evidence of type-R or type-C virus particles. It is important to recognize the presence of virus particles in hamster pancreatic carcinoma lines, since viruses could potentially affect biochemical or immunological studies on the carcinomas through the production of viral proteins that could be mistaken for tumor-associated antigens.

Molecular genetic analysis of the primary immunodeficiency disorders.

Exciting progress in the search for the genetic basis of the primary immune deficiency disorders continues to shed insight into functioning of the immune system in health and disease. The molecular genetic causes of 7 of the 17 WHO-recognized primary immune deficiency diseases have been defined. Additional studies will shed more insight into congenital and acquired immune deficiency disorders.

Retinoic acid binding protein in human and experimental pancreatic carcinomas in hamsters.

Cytoplasmic retinoic acid binding protein (cRABP) is present in human fetal pancreas and becomes nondetectable in the normal adult pancreas. The binding protein for retinoic acid becomes apparent again in pancreatic cancer. Similar fluctuations in the content of cRABP occur in the hamster. The binding protein is undetectable in the normal adult hamster pancreas, while it was detected in several transplantable adenocarcinomas in the Syrian golden hamster.

Production of monoclonal antibodies to Bruton's tyrosine kinase.

Bruton's X-linked agammaglobulinemia is caused by mutations in a cytoplasmic protein tyrosine kinase termed Bruton's tyrosine kinase (BTK). The protein is expressed in all members of the B cell lineage and is critical for B cell development. The protein consists of several modules, including a pleckstrin homology domain and the Src homology domains SH1, SH2, and SH3. We report here the production of monoclonal antibodies against the pleckstrin homology domain of human BTK. The antibody was produced by immunizing mice with a FLAG-BTK fusion protein. Hybridoma supernatants were screened by ELISA using a GST-BTK fusion protein as the antigen. Selected monoclonal antibodies recognize denatured BTK on Western blots of peripheral blood mononuclear cell lysates. Mouse BTK protein is also detected. These antibodies should be useful in assessing patients with immune deficiency, as well as in studying normal B cell development.

A monoclonal antibody 7G7/B6, binds to an epitope on the human interleukin-2 (IL-2) receptor that is distinct from that recognized by IL-2 or anti-Tac.

Murine splenocytes immune to influenza virus-activated human T-cells were fused with SP2/0 cells, selected in chemically defined HAT media, and subcloned to yield a monoclonal antibody (MAb) termed 7G7/B6. 7G7/B6 binds to lectin- and antigen-activated T-cells, but not resting T-cells or B-lymphoblastoid lines from the same donor. 7G7/B6 immunoprecipitates a 50-55 kD band from cell surface iodinated PHA-activated T-cells or the T-cell leukemia line HUT 102B2, as shown on SDS-PAGE. Cross-clearing studies demonstrate that 7G7/B6 binds the same cell surface molecule(s) as anti-Tac, a MAb which has been shown previously to recognize the human receptor for IL-2. 35S-methionine pulse chase experiments in HUT 102B2 cells reveal that 7G7/B6 binds to an early (less than 30 min) 35-37 kD and late (greater than 4 h) 50 kD protein. Sequential immunoprecipitations demonstrate that these are identical to the molecules identified by anti-Tac under similar conditions. However, only anti-Tac coprecipitates a higher molecular band at 110 kD. 7G7/B6 and anti-Tac do not competitively inhibit the binding of each other to PHA-activated T-cells. Functional studies reveal that in contrast to anti-Tac, 7G7/B6 has almost no inhibitory effect in vitro on IL-2-driven proliferation of IL-2-dependent T-cell lines, or alloimmune cytotoxic T-cell generation (however, once generated, these cytotoxic T-cells were both 7G7/B6 and anti-Tac positive). Finally, IL-2 does not inhibit the binding of 7G7/B6 to activated T-cells under conditions which result in up to 75% inhibition of anti-Tac binding. Therefore, 7G7/B6 is another MAb recognizing the human IL-2 receptor, but binding to an epitope distinct from that recognized by either IL-2 or anti-Tac.

Nitrosamine-induced pancreatic carcinogenesis in outbred and inbred Syrian hamsters.

Pancreatic carcinogenesis was investigated in outbred and in five strains of inbred Syrian golden hamsters utilizing the nitrosamines N-nitrosobis(2-hydroxypropyl)amine (BHP) and N-nitrosobis(2-oxopropyl)amine (BOP). Thirty eight outbred hamsters were treated for an average of 15 weeks with weekly s.c. inoculations of BHP at doses of 250,000 or 1000 mg/kg. Pancreatic carcinomas developed in 19%. Eighty nine inbred hamsters of strains CB, LHC and PD4 were given BHP at 250 mg/kg weekly for an average of 25 weeks. Pancreatic carcinomas developed in 61%. Pancreatic inflammation, fibrosis, and ductal hyperplasia were prominent. Toxic changes in the liver, biliary hyperplasia, and pulmonary interstitial inflammation were also prominent features of BHP-treated hamsters, along with occasional carcinomas of the liver and respiratory tract. One hundred and sixteen inbred hamsters of strains CB, LHC, LSH, MHA, and PD4 were treated with BOP at a dose of 5 mg/kg weekly for 15 weeks. The incidence of pancreatic carcinoma was 51%. BHP-treated hamsters exhibited pancreatic fibrosis and ductal hyperplasia. Livers of BHP-treated animals showed biliary hyperplasia, and lungs exhibited chronic inflammation. Occasional carcinomas of the liver and lung developed. From 243 hamsters treated with nitroso carcinogens, eight pancreatic ductal adenocarcinoma lines were derived that can be transplanted and propagated in inbred hamsters.

Targeting human IL-2 receptors for diagnosis and therapy.

The high-affinity interleukin-2 receptor (IL-2R) is a multichain receptor with at least three IL-2 binding chains: IL-2R alpha (55 kDa) bound by the monoclonal antibody anti-Tac, IL-2R beta (75 kDa) and Il-2R gamma (64 kDa). The IL-2R alpha also exists as a naturally occurring soluble molecule (sIL-2R alpha). We target the IL-2R for immune intervention since resting normal cells do not express the high-affinity IL-2R, whereas this receptor is on some cells in certain lymphoid neoplasias, select autoimmune disorders, and in individuals rejecting organ allografts. Treatments have included unmodified murine anti-Tac and radioisotopes conjugated to murine anti-Tac. Our emerging understanding of the IL-2R system continues to open possibilities for more specific immune intervention.

Defective specific antiinfluenza virus antibody production in vitro by lymphocytes from patients with ataxia-telangiectasia.

The ability of lymphocytes from 11 patients with ataxia-telangiectasia to produce specific antiinfluenza virus antibody in vitro was evaluated. Lymphocytes from these patients produced markedly less antibody than lymphocytes from normal controls when stimulated with type A influenza viruses. Additional studies were undertaken to evaluate the function of the B cells, T cells, and adherent cells of these patients in specific antibody production. B cells from the AT patients produced one-third to one-half as much antiinfluenza virus antibody as did B cells from normals when stimulated with the polyclonal activator Epstein-Barr virus or, in the two cases studied, when stimulated with influenza virus in the presence of normal HLA-identical T-cells, suggesting that a partial B-cell defect contributed to the deficient antibody response in these patients. Helper T-cell function of T-cells from two patients was evaluated in coculture with their HLA-identical sibling's B cells; these studies revealed that the patients' T-cells could provide less help than normals' T-cells but that this help was not entirely deficient. Furthermore, T-cells from AT patients could provide allostimulated helper T-cell function in coculture with allogeneic normal B cells. Taken together, these results suggest that partial defects of B- and T-cell function both contribute to the decreased antiinfluenza virus antibody production by patients with AT.

Induction and measurement of in vivo antibody responses.

The capacity of the human immune system to mount an antibody response following in vivo immunization with a protein or polysaccharide antigen is a revealing indication of the overall integrity of both the B and T cell arms of the immune system. As such, in vivo immunization followed by measurement of the antibody response is an appropriate test of immune function in the various acquired and congenital immunodeficiencies and in a host of other conditions affecting the immune system. This unit describes procedures for in vivo immunization and for the measurement of the subsequent immune response using an ELISA technique.

51Cr release assay of antibody-dependent cell-mediated cytotoxicity (ADCC).

Antibody-dependent cell-mediated cytotoxicity (ADCC) is an immunologic cytotoxic effector mechanism that is dependent on the cooperative interaction of humoral and cellular effector elements. This unit describes an assay of ADCC activity that can be used as a test for immunocompetence in effector cells or to test the activity of a monoclonal antibody to mediate ADCC. In this form of cytotoxicity, effector cells with receptors for the Fc portion of immunoglobulin produce target cell lysis by attachment to the Fc portion of antibodies that are bound to target cells via their antigen-combining sites. Therefore, an ADCC assay involves three essential components: labeled target cells, antibodies with specificity for target-cell surface antigens, and effector-cell populations. The basic protocol describes a method of measuring ADCC effector activity in lymphoid cells (peripheral blood mononuclear cells, or PBMC) that employs (51)Cr-labeled target cells. The three components are mixed in microtiter-plate wells and lysis of the target cells is detected by measuring the release of radioactivity into the cell supernatant. Support protocols describe procedures for preparing anti-target cell antiserum and (51)Cr-labeled target cells.

Soluble Tac peptide is present in the urine of normal individuals and at elevated levels in patients with adult T cell leukaemia (ATL).

The T lymphocyte-derived lymphokine interleukin 2 and the cell-associated receptor for this molecule play major roles in the activation and regulation of the human immune response. An enzyme-linked immunosorbent assay has been developed to measure quantitatively a soluble form of one component of the human interleukin 2 receptor, namely the Tac peptide. In the present studies, soluble Tac peptide was measured in the urine of normal individuals (mean = 92 U/ml), a level not significantly different (0.01 less than P less than 0.05) from the corresponding serum concentrations (mean = 175). The urinary Tac peptide had a molecular weight of 40-45 kD by sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis and specifically bound interleukin 2. Elevated levels of urinary Tac peptide were found in four patients with adult T cell leukaemia who also had elevated serum levels of Tac peptide. Thus, urine may represent a valuable source of lymphokine-binding proteins that may serve as important markers of immunological activation.

Antigen-stimulated human B cell clones are committed to the production of a single class of antibody in vitro.

We have investigated the isotype(s) of antibody produced in vitro by antigen-stimulated human B cell clones. An analysis of the class(es) of antibody produced in multiple replicate cultures containing a mean of less than one precursor B cell per well was consistent with the hypothesis that individual B cell precursors produced a single class of antibody. This result was obtained by using cells isolated from either the peripheral blood or tonsils. Thus, under the culture conditions utilized, no intraclonal isotype switching was detected.

An analysis of the cellular requirements for the production of soluble interleukin-2 receptors in vitro.

Following activation in vitro, peripheral blood mononuclear cells (PBMC) express cell-associated interleukin-2 receptors (IL-2R) and also release soluble IL-2R into culture supernatants. The present studies were undertaken to define which normal cells were responsible for the release of soluble IL-2R in vitro. Both cell-associated and soluble IL-2R were quantitatively measured with a "sandwich" enzyme-linked immunoassay employing two monoclonal antibodies. PBMC were separated into populations of surface immunoglobulin-negative cells (T cells and monocytes) and surface immunoglobulin-positive cells (B cells and monocytes), and the T-cell population was further separated into OKT4-positive (OKT4+) cells and OKT4-negative (OKT4-) cells. Following activation with phytohemagglutinin, pokeweed mitogen, and the monoclonal antibody OKT3, large amounts of soluble IL-2R were released by PBMC, unseparated T cells, OKT4+ T cells, and OKT4- T cells. The population containing B cells and monocytes made small but readily detectable amounts of soluble IL-2R when stimulated with these T-cell mitogens; likely the result of contaminating T cells in the population. However, when highly purified B cells were stimulated with Staphylococcus aureus Cowan and recombinant IL-2, they also released small amounts of soluble IL-2R. The release of soluble IL-2R by T cells appeared monocyte dependent when OKT3, but not phytohemagglutinin, was employed for activation, and monocytes themselves released no detectable IL-2R under the conditions employed. These studies define the cellular requirements for the release of soluble IL-2R in vitro and demonstrate that such receptors are released by B cells, T cells, and both OKT4+ and OKT4- T-cell subsets.

The production of soluble and cellular interleukin-2 receptors by cord blood mononuclear cells following in vitro activation.

Cord blood mononuclear cells (CBMC) were investigated for their capacity to generate both cellular and soluble, supernatant interleukin-2 receptors (IL-2R) following cellular activation in vitro. Soluble IL-2R were measured in cell-free supernatants and in detergent-solubilized cell extracts with a "sandwich" enzyme-linked immunosorbent assay. CBMC and adult peripheral blood mononuclear cells were activated with phytohemagglutinin or the murine monoclonal antibody OKT3. CBMC and adult peripheral blood mononuclear cells generated cellular and soluble IL-2R in response to both activators. Peak values for supernatant IL-2R were observed on day 7, while peak values of cell-associated IL-2R occurred on day 5, followed by a decline on day 7. With the exception of supernatant IL-2R production induced by OKT3 stimulation, CBMC produced IL-2R in amounts comparable to adult mononuclear cells. Cord blood plasma also contained amounts of IL-2R comparable to that found in adult sera/plasma. Thus, CBMC appear largely immunocompetent with regard to the expression of IL-2R.

IL-15 induces the release of soluble IL-2Ralpha from human peripheral blood mononuclear cells.

The recently identified and cloned cytokine IL-15 shares many of the T-cell and B-cell stimulatory activities of IL-2 and utilizes the beta and gamma chains of the IL-2R for binding and signaling. The present report shows that, like IL-2, IL-15 in a concentration and time-dependent manner causes the release of sIL-2Ralpha from PHA-activated human peripheral blood mononuclear cells. This effect of IL-15 is largely direct and independent of IL-2. Blocking of the IL-2Rbeta chain with the antibody Mik-beta1 prevented the release of sIL-2Ralpha by IL-15 but not by IL-2. IL-7, another cytokine utilizing the gamma chain of the IL-2R, drove the release of sIL-2Ralpha as well. Several clinical conditions are associated with abnormal serum sIL-2Ralpha levels and are also monitored by the measurement of sIL-2Ralpha. The reason for sIL-2Ralpha release is not fully understood. In this study, IL-15, like IL-2 was shown to be a potent inducer of sIL-2Ralpha release in vitro.

Elevated concentrations of soluble interleukin-2 receptors in serum samples and bronchoalveolar lavage fluids in active sarcoidosis.

Sarcoidosis is a granulomatous disorder of unknown cause characterized by activation of T-lymphocytes. We here report the use of an enzyme-linked immunosorbent assay for the soluble interleukin-2 receptor (IL-2R) as a measure of T-cell activation in serum samples and bronchoalveolar lavage fluids in 15 patients with active sarcoidosis. The geometric mean (x divided by SEM) value for soluble IL-2R in serum samples from patients with sarcoidosis was 1,110 (x divided by 1.17) versus 224 (x divided by 1.08) U/ml for normal control subjects (p less than 0.001). Detectable levels of soluble IL-2R were present in bronchoalveolar lavage fluids from 10 of 15 patients with sarcoidosis versus only 2 of 36 normal control subjects (p less than 0.001). Levels of soluble IL-2R in serum samples from untreated patients with sarcoidosis correlated with 67gallium lung scanning scores (p less than 0.05) but not with serum angiotensin-converting enzyme concentrations or constituents of bronchoalveolar lavage. In 5 patients, the level of soluble IL-2R in serum samples fell from 1,499 (x divided by 1.20) to 476 (x divided by 1.58) U/ml (p less than 0.05) after 6 wk of successful treatment with corticosteroids, whereas the changes in soluble IL-2R in bronchoalveolar lavage fluids were more variable. These observations suggest that measurements of soluble IL-2R, particularly in serum samples, may reflect disease activity and be clinically useful in the management of patients with sarcoidosis.

Molecular genetic analysis of X-linked hypogammaglobulinemia and isolated growth hormone deficiency.

In 1980 the clinical syndrome of X-linked hypogammaglobulinemia and isolated growth hormone deficiency (XLA/GHD) was described. XLA/GHD patients have reduced serum levels of Ig and normal cell-mediated immunity, and thus resemble patients with Bruton's X-linked agammaglobulinemia (XLA). However, XLA/GHD patients also have isolated GHD. Mutations and deletions in the Bruton's tyrosine kinase gene (BTK) are responsible for Bruton's XLA. We investigated BTK gene expression in an XLA/GHD patient from the family originally described by Northern analysis, cDNA sequencing, and Western analysis of protein production using mAb to BTK. BTK mRNA was normal in size and abundance, and the mRNA sequence was normal over the coding region, except for a single silent mutation. BTK protein was present in normal amounts in PBMC of this patient. Thus, at the molecular level, XLA/GHD is a different disease entity from Bruton's XLA. These results suggest that undescribed genes critical for B cell development and growth hormone production exist on the X chromosome.