Successful bone marrow transplantation with split lymphoid chimerism in DiGeorge syndrome

A female infant with DiGeorge syndrome associated with severe T-cell immunodeficiency underwent a successful bone marrow transplantation from her HLA-identical, mixed leukocyte culture-nonreactive brother at 5 months of age. Mature circulating T cells and mitogen-induced proliferative responses were detectable at 10 days posttransplant, and by 8 months post-transplant functional T- and B-cell reconstitution was documented by normal responses to mitogens and normal levels of serum immunoglobulins as well as in vitro and in vivo T-cell reactivity to specific antigens and production of specific antibody to T cell-dependent antigens in vivo. Phytohemagglutinin-induced interleukin-2 production and cell surface interleukin-2 receptor expression improved posttransplant, with normal production values observed by 8 months posttransplant. Histologic examination of appendix and thoracic lymph node obtained 9 and 17 months posttransplant, respectively, revealed near-normal lymphoid architecture, with germinal center formation providing morphologic confirmation of reconstitution. Stable split lymphoid chimerism with T cells of donor origin and B cells remaining recipient in origin was documented by sex chromosome analysis. Two years posttransplant the subject remains free of serious infections. In conclusion, this case indicates that bone marrow transplantation can produce peripheral immunoreconstitution without need for significant thymic influence, most likely by providing a source of postthymic T cells, and that bone marrow transplantation should be considered a therapeutic option in patients with DiGeorge syndrome associated with severe T-cell deficiency.

New methodologies. Their role in pediatric pathology

Recombinant DNA technology is providing the means for early and specific etiologic diagnoses of infectious and immunologic diseases, replacing or complementing older methodologies. The new tools that have been so useful in detecting gene rearrangements in leukemias and lymphomas are being applied to the unresolved questions of embryogenesis and disorderly cell differentiation and are being used to completely re-map the nervous system. Flow cytometry and cell sorting are becoming standard features of clinical laboratories and are instrumental not only in defining alterations in lymphoid cell populations but in examining cellular functions as well as surface markers. Bone marrow and organ transplantation for genetic, metabolic, and neoplastic diseases will be performed much more effectively as these newer technologies are applied to the selection of compatible donors and to the follow-up of rejection and infectious complications.

Burkitt's lymphoma developing in a 7-year-old boy with hyper-IgE syndrome

We report a case of Burkitt's lymphoma developing in a 7-year-old boy with hyper-IgE syndrome. This is the third reported case of malignancy in the hyper-IgE syndrome. The other two cases were an 18-year-old man with Hodgkin's disease and a 10-year-old girl with histiocytic lymphoma. The patient developed retroperitoneal Burkitt's lymphoma with probable metastasis to the brain. His short life was characterized by recurrent staphylococcal skin, middle ear, and lung infections associated with extremely elevated serum concentrations of IgE. There was also an associated disturbance of bone metabolism with osteoporosis and pathologic fractures and absence of parathormone, findings that have been observed in other patients with hyper-IgE syndrome and other forms of T cell immunodeficiency. At the age of 5 years, inadequate B cell responses to immunization with antigens derived from diphtheria, tetanus, and Haemophilus influenzae type b organisms and with the OX174 bacteriophage were demonstrated in the patient. In his terminal state his in vitro lymphocyte analysis demonstrated findings of anergy. Although the precise immunologic defect in hyper-IgE syndrome is unknown, these cases of associated malignancy stress the role that a completely normal immune system plays in preventing the premature appearance of cancer.

Radioimmunoassay for anti-actin antibody: application in viral and autoimmune diseases

The development of a non-competitive, solid-phase radioimmunoassay for quantitating anti-actin antibody is described. Anti-actin antibody was captured on BSA-coated microspheres of polystyrene to which a synthetic peptide representing the fifteen amino acid N-terminus of human beta-actin was covalently attached. A rabbit antiserum against the actin peptide fragment was used as reference serum for the assay. Serums of 23 out of 28 (82%) patients with chronic active hepatitis, shown to have anti-actin antibodies (range 2-140 micrograms ml-1) by immunofluorescence and immunoblot assays, were used to validate the radioimmunoassay. Only 7 out of 130 (5%) control subjects exhibited anti-actin antibody serum concentrations above 14 micrograms ml-1 (range 2-20 micrograms ml-1), the 95% confidence interval. Anti-actin antibody serum concentrations were determined to be elevated in 28 out of 47 (60%) patients with juvenile rheumatoid arthritis (range 5-89 micrograms ml-1), 43 out of 64 (67%) patients with human immunodeficiency virus infection and AIDS (range 3-80 micrograms ml-1), and 17 out of 23 (74%) infants with Kawasaki Syndrome (range 7-138 micrograms ml-1). All of the differences observed between patient groups, either singly or collectively, and the control group are highly significant (P less than 0.001) as judged by chi-square analysis. Since all of these disease states contain elements of viral infection and autoimmune disease, it is possible that viral infection in these diseases triggers the production of anti-actin antibody, possibly by means of molecular mimicry in response to viral oncogenes or to abnormal expression of actin in host tissue. This radioimmunoassay for anti-actin antibodies may prove to be a useful tool for the detection and monitoring of certain forms of autoimmune disease.

Modulation of a human lymphoblastoid B cell line by cyclic AMP. Ig secretion and phosphatidylcholine metabolism

A transformed human B cell line, LA350, was found to be sensitive to cAMP-elevating agents by responding with rapid (0 to 2 h) severalfold elevations of intracellular cAMP to treatment with cholera toxin, isobutylmethylxanthine (IBMX), forskolin, and dibutyryl cAMP (all p less than 0.001). These cAMP-elevating agents also produced significant inhibitions of subsequent (48 to 72 h) Ig secretion by the same B cells as measured by a reverse hemolytic plaque assay and an enzyme-linked immunoadsorbent assay for IgM (both p less than 0.001). PMA- and IBMX-treated cells were particularly responsive to the effects of cholera toxin, showing a doubling of cAMP content and profound decrease in Ig production (p less than 0.001). Because our previous studies had correlated activation of the metabolic turnover of the phosphatidylcholine (PC) fraction of membrane phospholipids with enhanced Ig secretion, we examined the sensitivity of PC metabolism to cAMP in control and PMA-stimulated cells. Formation of PC was found to be inhibited by forskolin and IBMX (both p less than 0.002) but breakdown of PC was stimulated (p less than 0.001). These findings imply that as the enzymatic products of PC, choline phosphate and diacylglycerol, are depleted due to the combined effects of cAMP upon synthesis and turnover of PC, there is a decrease in Ig secretion. Since diacylglycerol activates protein kinase C, it appears reasonable that Ig secretion is at least partially regulated by cAMP-responsive alterations in PC metabolism produced by protein kinase C-induced phosphorylation. We conclude that the early cAMP-sensitive changes in PC metabolism in this activated B cell line may signal for subsequent alterations in Ig secretion.

Modulation of a human lymphoblastoid B cell line by cyclic AMP. Ig secretion and phosphatidylcholine metabolism

A transformed human B cell line, LA350, was found to be sensitive to cAMP-elevating agents by responding with rapid (0 to 2 h) severalfold elevations of intracellular cAMP to treatment with cholera toxin, isobutylmethylxanthine (IBMX), forskolin, and dibutyryl cAMP (all p less than 0.001). These cAMP-elevating agents also produced significant inhibitions of subsequent (48 to 72 h) Ig secretion by the same B cells as measured by a reverse hemolytic plaque assay and an enzyme-linked immunoadsorbent assay for IgM (both p less than 0.001). PMA- and IBMX-treated cells were particularly responsive to the effects of cholera toxin, showing a doubling of cAMP content and profound decrease in Ig production (p less than 0.001). Because our previous studies had correlated activation of the metabolic turnover of the phosphatidylcholine (PC) fraction of membrane phospholipids with enhanced Ig secretion, we examined the sensitivity of PC metabolism to cAMP in control and PMA-stimulated cells. Formation of PC was found to be inhibited by forskolin and IBMX (both p less than 0.002) but breakdown of PC was stimulated (p less than 0.001). These findings imply that as the enzymatic products of PC, choline phosphate and diacylglycerol, are depleted due to the combined effects of cAMP upon synthesis and turnover of PC, there is a decrease in Ig secretion. Since diacylglycerol activates protein kinase C, it appears reasonable that Ig secretion is at least partially regulated by cAMP-responsive alterations in PC metabolism produced by protein kinase C-induced phosphorylation. We conclude that the early cAMP-sensitive changes in PC metabolism in this activated B cell line may signal for subsequent alterations in Ig secretion.

Clonal analysis of transplant-associated lymphoproliferations based on the structure of the genomic termini of the Epstein-Barr virus

The clonal composition of various transplant-associated lymphoproliferations was assessed by means of Southern blot hybridizations using a DNA probe specific for the fused termini of the Epstein-Barr virus (EBV) genome. A single clonal band representing the joined EBV genomic termini was detected in most biopsies, demonstrating the presence of a monoclonal expansion of B lymphocytes carrying EBV DNA. Different configurations of immunoglobulin gene rearrangements and fused EBV genomic termini were frequently observed in tissues from different biopsy sites in individual patients, confirming the multiclonal origins for these lymphomas. In rare specimens, multiple forms of the joined termini were detected within individual lesions, which appeared polymorphous by histologic methods of analysis and polyclonal by immunologic and immunogenetic methods of analysis. These studies confirm that there is a spectrum of EBV-associated disorders of varying clonal composition that may arise in immunosuppressed organ-allograft recipients. The data are consistent with the proposal that the lymphoproliferations initiate as polyclonal expansions of EBV-carrying B cells, which progress to multiclonal lymphomas in most patients. Detection of homogeneous episomal EBV DNA in most lesions supports a primary role for the virus in the pathogenesis of these disorders.

Phorbol ester binding to a human lymphoblastoid B-cell line, LA350, stimulates 32P incorporation into selected phospholipids and immunoglobulin secretion

Anti-mu antibody binds to surface IgM on LA350, a transformed human B-cell line, and causes the immediate (5 min) hydrolysis of phosphatidylinositol (PI) into inositol 1,4,5-triphosphate (IP3) and diacylglycerol followed by a subsequent (48-72 hr) increase in immunoglobulin M (IgM) production. Phorbol myristate acetate (PMA) in a dose-dependent fashion inhibited completely the anti-mu-stimulated hydrolysis of PI and its resynthesis (PI cycle) from phosphatidic acid (PA) (P less than 0.001). Phorbol dibutyrate (PD), but not the inactive methyl ester derivative of PMA (PMA-ME), inhibited the anti-mu stimulation of the PI cycle (P less than 0.001). Conversely, PMA and PD, but not PMA-ME, stimulated in a dose-dependent fashion the metabolic events consistent with an activation of a putative phosphatidylcholine (PC) cycle. For example, at 10(-8) M PMA there was a 300% increase in the acute (1 hr) incorporation of [3H]choline into PC (P less than 0.001), a 680% increase in the acute (1 hr) incorporation of 32P into PC (P less than 0.001), but no net synthesis of PC as measured by the lack of PMA-stimulated incorporation of 32P into PC in LA350 prelabeled for 24 hr. Also in cells labeled to equilibrium with [3H]choline and in pulse-chase experiments we established that PMA produces a rapid incorporation of choline phosphate into PC and a rapid breakdown of PC, yielding choline metabolites released as choline itself into external medium surrounding the cell. Binding studies with [3H]PD demonstrated a dissociation constant of 20 mM and 5.3 x 10(5) total binding sites per cell. PMA was as effective as cold PD in inhibiting [3H]PD binding (P less than 0.001), but PMA-ME was ineffective. PMA and PD, but not PMA-ME, produced a similar dose-dependent (maximal at 10(-8) M) increase (300%) in immunoglobulin production as measured by either an ELISA assay or a reverse hemolytic plaque assay (P less than 0.001). Thus, activation of either the PI or the PC cycle results in significant enhancement in immunoglobulin production in LA350. Although PMA turns off the PI cycle, it turns on the PC cycle. A common mechanism to explain these findings might be the activation of protein kinase C, indirect via diacylglycerol release in the PI cycle stimulation by anti-mu and direct in the PC cycle stimulation by PMA by virtue of direct binding to protein kinase C.

Anti-mu antibody stimulates the phosphatidylinositol cycle and immunoglobulin secretion in a human lymphoblastoid B-cell line, LA350

Within 5 min of the binding of anti-mu antibody (anti-mu) to surface IgM on LA350, a human lymphoblastoid B-cell line, there was a significantly enhanced incorporation of 32P into the phosphatidic acid (PA) and phosphatidylinositol (PI) fractions of cellular phospholipids and the magnitude of the early increase in PA was twice as great as that in PI. This anti-mu-enhanced incorporation of 32P into PA and PI required the binding of a divalent form of antibody (IgG or F(ab')2), was blocked by coincubation with micromolar concentrations of soluble IgM, was decreased by incubation of cells at temperatures lower than 37 degrees C, and was inhibited by coincubation with millimolar concentrations of dibutyryl cyclic AMP and theophylline. Similar incorporation studies with [3H]inositol demonstrated a selective and significant increase in labeling of PI. In LA350 labeled with [3H]inositol for 30 hr (equilibrium) and acutely stimulated by anti-mu, specific hydrolysis of phosphorylated PI (PI 4,5-bisphosphate) was measured by the significantly increased release at 15 min of radioactive inositol 1,4,5-trisphosphate, inositol 1,4 bisphosphate, and inositol 1-phosphate. The release of these inositol phosphates was significantly augmented by coincubation with 0.01 M LiCl which prevented their simultaneous enzymatic degradation. All of these findings are consistent with an activation of a linked series of metabolic events known as the PI cycle. In similar cell cultures anti-mu significantly stimulated the secretion of IgM by LA350 as measured at 48 hr in a reverse hemolytic plaque assay. Two other IgM-bearing human lymphoblastoid B-cell lines which gave no evidence of turnover of 32P in PA and PI in response to binding by anti-mu likewise failed to enhance their secretion of IgM. We conclude that the binding of surface IgM on LA350 by anti-mu results in the generation of a transmembrane signal which causes a rapid activation of the PI cycle which itself may play a role in the subsequent increase in IgM secretion.

Epstein-Barr virus-transformed B-cell line (DV-1) derived from bone marrow of a patient with severe combined immunodeficiency and immunoblastic lymphoma

An Epstein-Barr virus-transformed B-cell line derived from a patient with severe combined immunodeficiency who died of a lymphoreticular malignancy has been characterized. The line derived from bone marrow cultures and designated DV-1 shows surface and cytoplasmic IgM and staining with fluorescent monoclonal antibodies against immunoglobulin heavy and light chains mu, delta, and kappa, Dr, and several other B-cell surface antigens. DV-1 secretes IgM kappa and demonstrates monoclonality on analysis of immunoglobulin heavy and light chain gene rearrangement patterns. Incubation with either phytohemagglutinin or pokeweed mitogen failed to cause significant stimulation of proliferation of DV-1 and another EBV-transformed B-cell line derived from an immunologically normal host (LA-350), whereas incubation with Staphylococcus aureus Cowan strain 1 led to significant inhibition of DV-1 and LA-350. Rabbit IgG antibody specific for human immunoglobulin mu-chains produced a dose dependent stimulation of both lines. The responses of DV-1 and LA-350 to mitogens and anti-mu were not as high as those of normal peripheral blood lymphocytes. This spontaneously derived Epstein-Barr virus-transformed B-cell line from a patient with severe combined immunodeficiency demonstrated functional characteristics similar to a B-cell line derived from an immune competent host. While these cells spontaneously incorporate 200 times more thymidine than normal resting peripheral blood lymphocytes, they retain their ability to be modulated by antiimmunoglobulin, and staphylococcal Cowan strain 1, but are unresponsive to the effects of B-cell growth factor.

Antibody to human lymphocyte actin regulates immunoglobulin secretion by an EBV-transformed human B-cell line

Antibody against actin isolated from a human EBV-transformed lymphoblastoid B-cell line exerted an inhibitory effect on in vitro IgM secretion by a different lymphoblastoid B-cell line, LA350. This effect was dose dependent showing from 24-40% inhibition at a dilution of 1:100 and 68-80% inhibition at a dilution of 1:50. This effect was noted in the absence of changes in either total cell count or [3H]-thymidine incorporation and was reversed by co-incubation with purified rabbit thymus actin (100 micrograms/ml) but not bovine serum albumin at the same concentration. These data demonstrate regulation of immunoglobulin synthesis by antibodies against human lymphocyte derived actin in a lymphoblastoid B-cell line.

Environmental control in management of immunodeficient patients: experience with "David"

Environmental control in managing patients with immunodeficiency ranges from the exceedingly complex to the relatively simple. At one end of the spectrum is the total isolation technology applied to David, the "Bubble Boy" who lived his entire life behind sterile plastic barriers. At the other end of the spectrum is the simpler technology applied to patients receiving bone marrow transplants who are maintained in ordinary private hospital rooms and attended by personnel who merely observe handwashing precautions. Most properly performed and controlled studies of the use of special isolation procedures to reduce infections derive from patients receiving bone marrow transplants for conditions of aplastic anemia and leukemia or patients receiving chemotherapy for malignancy. The design of isolation procedures for immunodeficient patients borrows from these studies because of the relatively small number of immunodeficient patients. These studies have shown that laminar airflow rooms produce a significantly lower incidence of infections but may not change the mortality of all patients. Also, protective isolation has clearly reduced the incidence and severity of graft-versus-host disease in transplanted patients with aplastic anemia. Recently there has been a trend away from strict isolation procedures because careful studies have indicated that host rather than acquired pathogens are responsible for at least 85% of infections in these special patients. Also, the human stress of prolonged isolation is becoming increasingly recognized. The complex and expensive isolation techniques that were used in David's case are no longer being utilized in immunodeficient subjects, partly because new transplantation technology has made it possible to cross histocompatibility barriers, obviating the need for permanent isolation.

Monoclonal anti-actin antibody recognizes a surface molecule on normal and transformed human B lymphocytes: expression varies with phase of cell cycle

A monoclonal anti-actin antibody, 2C9, was used to study the distribution of an actin-like cell-surface antigen (hereafter termed actin) on a lymphoblastoid cell line LA350 and on human peripheral blood lymphocytes. It was determined that 8-40% of LA350 cells and 3-15% of peripheral blood lymphocytes from healthy donors stain specifically with 2C9, almost exclusively on IgM-positive cells. Treatment of cells with 2C9 prior to incubation caused cell-surface actin to first patch and then to cap. Treatment of cells with nonspecific protease caused a loss of surface actin, with reexpression of the marker after 8-12 hr. The expression of LA350 surface actin also increased with DNA synthesis and was demonstrated to be maximal during late G1/early S phase. Thus, this antigen may be a sensitive marker for activated lymphocytes. These studies contribute to our understanding of the expression and distribution of actin-like membrane proteins that may participate in regulatory signals mediated by anti-actin antibody.

Permanent intrinsic B cell immunodeficiency caused by phenytoin hypersensitivity

We report a patient who, 3 weeks after initiation of therapy, experienced a hypersensitivity reaction to phenytoin manifested as rash, lymphadenopathy, elevated serum transaminase levels, and subsequent panhypogammaglobulinemia with IgG, 180 mg/dl (control range 639 to 1349); IgA, 15 mg/dl (control range 70 to 312); and IgM, 0 mg/dl (control range 56 to 352). Repeated in vitro lymphocyte analysis documented normal T cell-mediated immunity including T cell surface markers (E rosettes), lymphocyte proliferation after mitogen stimulation, and T cell phenotypes (T4 or helper and T8 or suppressor cells). However, the patient had a paucity of circulating B-lymphocytes as assessed by the number of lymphocytes with surface membrane immunoglobulin (patient value of 0 compared to the control range 16 to 435 cells per microliter of blood) and by the number of lymphocytes bearing the B1 antigen (patient value of 13 compared to the control range 48 to 358 cells per microliter of blood). Hemolytic plaque assay revealed decreased immunoglobulin production (number of immunoglobulin-secreting cells per million circulating mononuclear cells) as compared to control subjects (patient unstimulated mean of 100 as compared to a control mean of 1753) and minimal enhancement on stimulation with pokeweed mitogen (patient stimulated mean of 250 as compared to control mean of 8946). Coculture experiments with the reverse hemolytic plaque assay revealed no evidence of suppression. No reversal of this patient's immunodeficiency has occurred 3 years after phenytoin withdrawal.

Immunodeficiency secondary to structural intestinal defects. Malrotation of the small bowel and cavernous hemangioma of the jejunum

Two patients with gastrointestinal tract abnormalities were discovered to have significant defects in both humoral and cellular immunity. Patient 1, a 4-year-old girl with suspected food allergy, failure to thrive, and chronic diarrhea, exhibited a decreased serum IgG immunoglobulin level, decreased numbers of peripheral blood T lymphocytes (erythrocyte rosettes), decreased numbers of T-lymphocyte subpopulations (T3+, T4+), decreased responses of lymphocytes to common mitogens, and absent in vivo responses to delayed hypersensitivity skin test antigens. Patient 2, a 3-year-old girl with chronic anemia, presented with immunological abnormalities similar to those of patient 1. On investigation, both patients were found to have significant structural abnormalities of the gastrointestinal tract. Patient 1 had a malrotation of the small bowel, while patient 2 had a cavernous hemangioma of the mid-jejunum. Following surgical correction of the gastrointestinal abnormalities, there was improvement in all immunologic values. By ten to 18 months after surgery, both patients demonstrated normal immunological function. Thus, anatomic lesions of the gastrointestinal tract that mimic more common childhood disorders, such as food allergy and anemia, may produce serious states of secondary immunodeficiency.

Characterization of complexes containing protein A and rabbit immunoglobulin G or Fc gamma fragments

Soluble complexes prepared over a range of molar ratios of [125I] protein A (SpA) and rabbit [131I]immunoglobulin G (IgG) or [131I]Fc gamma fragments were separated by ultracentrifugation in a sucrose gradient and selectively radioimmunoprecipitated with chicken antibodies that bind free or complexed SpA. With excess [125I]SpA the only complexes formed were composed of one molecule of labeled ligand and one molecule of [125I]SpA (1:1 complexes). With excess ligand the only complexes formed corresponded to [(IgG)2SpA]2 or [(Fc gamma)2SpA]2 (4:2 complexes). The 4:2 complex likely is responsible for several of the biological activities associated with SpA, including activation of humoral and cellular immune mechanisms, which are optimal under conditions of excess IgG.

Anti-rabbit thymus actin antibody inhibits proliferation of Epstein-Barr virus-transformed human B cell line LA350: augmentation by cyclic AMP

Antibody to actin isolated from the rabbit thymus gland exerted a dose-dependent inhibitory effect upon the proliferation of an Epstein-Barr virus-transformed human B cell line, LA350. Purified rabbit thymus actin specifically reversed the inhibitory effect of antibody by competing with surface actin on LA350. For example, LA350 proliferation at 48 hr was inhibited 90% at a 1:10 antibody dilution (p less than 0.001) but only 48% and 20% in the presence of 190 and 380 micrograms/ml of rabbit thymus actin, respectively (p less than 0.001 for reversal). Cyclic AMP augmented in a dose-related fashion the inhibitory effects of antibody, e.g., a 1:20 dilution of antibody inhibited 10, 19, 41, and 67% at 0.0, 0.5, 1.0, and 2.0 mM cAMP, respectively (p less than 0.001). We conclude that anti-actin antibody recognizes surface actin on a human B cell line and produces a functional inhibition of proliferation by a process that is augmented by cAMP.

Identification of L-cell growth stimulating antibody as anti-actin

Anti-L-cell antisera having potent cell growth stimulatory properties were shown by Western blotting to have predominant specificity toward a protein with a molecular weight of 42K which we identified as actin. Extractions of L cells, based upon the known insolubility of cytoskeletal proteins (including actin) in Triton X-100 and the solubility of actin in low ionic strength Ca2+ and ATP-containing buffer, led to actin-enriched preparations that retained immunoreactivity with the anti-L-cell antisera. The 42-kDa antigen binds to deoxyribonuclease I, has a pI = 5.2-5.4, and has an amino acid composition, including the presence of 3-methylhistidine, compatible with compositions determined for actins from other sources. Rabbit antiserum specific for this 42-kDa protein, isolated by SDS-PAGE, reproduced the cell growth stimulation by the anti-L-cell antisera and absorption of the antiserum with purified L-cell actin eliminated this stimulation. Moreover, these antibodies bind to the microfilaments of 3T3 fibroblasts. When purified actins were used as soluble antigen inhibitors of the immune reactivity of antiserum to 42-kDa protein with intact L cells, rabbit thymus actin competed with the surface molecules on L cells and reduced the stimulatory effect of the antiserum by 80% at an actin concentration of 150 micrograms/ml. Chicken muscle actin reduced the antibody stimulation effect by only 24% at the same protein concentration, and mouse muscle actin was ineffective as an inhibitor. The F(ab')2 fraction of anti-42K IgG was effective in stimulating L cells, thus documenting the immune nature of the actin-anti-42K interaction. We conclude that anti-actin antibodies, upon binding to actin-like cell surface determinants on L cells, stimulate cellular metabolism.

Mitogen-like monoclonal anti-actin antibodies

Monoclonal antibodies (IgM kappa) have been produced to actin isolated electrophoretically from L cell extracts. These monoclonal anti-actin antibodies bind to intact L cells and modulate DNA synthesis and cell proliferation, much like affinity-purified polyclonal rabbit antibody to the same Mr 42,000 actin. In addition, monoclonal antibodies specific for actin from Entamoeba histolytica also bound to and modulated the growth of L cells. A monoclonal antibody directed against a neuroblastoma surface antigen did not produce stimulation of L cells, and the binding activity of anti-actin monoclonal antibody to L cells was removed by absorption with actin covalently coupled to Sepharose. These observations demonstrate the specificity of interaction between the anti-actin monoclonal antibodies and the surface of intact L cells. We conclude that a surface actin-like molecule on the L cell, when bound by specific monoclonal antibody, initiates a stimulatory signal which results in enhanced cellular metabolism.

Mitogen-like monoclonal anti-actin antibodies

Monoclonal antibodies (IgM kappa) have been produced to actin isolated electrophoretically from L cell extracts. These monoclonal anti-actin antibodies bind to intact L cells and modulate DNA synthesis and cell proliferation, much like affinity-purified polyclonal rabbit antibody to the same Mr 42,000 actin. In addition, monoclonal antibodies specific for actin from Entamoeba histolytica also bound to and modulated the growth of L cells. A monoclonal antibody directed against a neuroblastoma surface antigen did not produce stimulation of L cells, and the binding activity of anti-actin monoclonal antibody to L cells was removed by absorption with actin covalently coupled to Sepharose. These observations demonstrate the specificity of interaction between the anti-actin monoclonal antibodies and the surface of intact L cells. We conclude that a surface actin-like molecule on the L cell, when bound by specific monoclonal antibody, initiates a stimulatory signal which results in enhanced cellular metabolism.

Monoclonal anti-actin antibody modulates expression of surface antigen on L cells

Monoclonal anti-actin antibody which is known to stimulate DNA synthesis and cell growth in a murine transformed cell line, L cell, was examined for its ability to modulate the expression of surface antigen on the cell membrane. There was a time dependent increase in the number of cell surface antigen molecules on L cells stimulated by monoclonal anti-actin antibody as measured by indirect immunofluorescence and flow cytometry. For L cells incubated for 12, 24, 48, 72, and 96 hours with monoclonal anti-actin antibody versus a myeloma control supernatant, the percentage of cells exhibiting high intensity immunofluorescence was 29 vs. 13, 13 vs. 10, 34 vs. 1, 52 vs. 11, and 35 vs. 18, respectively. We conclude that monoclonal anti-actin antibody modulates the time dependent surface expression of actin on L cells. It is likely that this modulated expression of surface actin-like molecules plays an important role in the transmission of stimulatory signals to the cells which result in enhanced cellular metabolism and proliferation.

Cyclic AMP and theophylline enhance DNA synthesis in L cells stimulated with anti-actin IgG and [(IgG)2 protein A]2 complex by recruiting cells into S-phase

Surface binding of anti-actin IgG alone or in a Mr = 716 000 [(IgG)2 Protein A]2 complex results in a stimulation of DNA synthesis and cell growth in L cells. Cyclic-AMP (0.01-1.0 mM) added to such cell cultures augmented DNA synthesis as measured by incorporation of [3H]thymidine into DNA. Theophylline (0.1-1.0 mM), a phosphodiesterase inhibitor which prevents enzymatic breakdown of cAMP, had similar effects, but cGMP (0.01-1.0 microM) reversed the effects of cAMP and theophylline upon DNA synthesis. Analysis of the cell cycle by flow cytometry revealed that antibody produced a shift (7%) of cells from the G1-phase to the S-phase (DNA-synthetic) of the cell cycle at 72 hr of incubation. Addition of cAMP (0.5 mM) to cell cultures, however, produced significant shifts of antibody stimulated cells from G1-phase to S-phase at all time points measured, i.e., 24 (12%), 48 (22%), 72 hr (23%). Thus, antibody recruited cells into S-phase of the cell cycle and cAMP greatly augmented the effect. These observations suggest that the mechanism of activation of L cell growth by antibody to surface antigens involves a recruitment of cells into the DNA-synthetic phase and that the effect may be mediated by cAMP.

Epstein-Barr virus-associated B-cell proliferations of diverse clonal origins after bone marrow transplantation in a 12-year-old patient with severe combined immunodeficiency

A 12-year-old boy with severe combined immunodeficiency who had been kept in a gnotobiotic environment since birth received bone marrow from a histoincompatible sibling in an attempt to reconstitute immunologic function. To prevent graft versus host disease, the donor's marrow was treated in vitro with monoclonal antibody and complement to remove alloreactive T cells. Eighty days after transplantation, the patient had a systemic illness characterized by fever, thrombocytopenia, gastrointestinal pain, and bleeding; he died on the 124th post-transplantation day. Postmortem examination revealed multiple tumor-like B-cell proliferations, recipient in origin, in numerous organs. Epstein-Barr virus (EBV) was isolated from the patient's pharyngeal secretions; EBV nuclear antigen was found in spontaneously transformed peripheral-blood lymphocytes, inflammatory cells from peritoneal fluid, and bone marrow cells; and EBV genomes were discovered in all tumor tissues. The donor's serum showed evidence of past EBV infection. Analysis of cellular immunoglobulin and immunoglobulin gene DNA from the tumors indicated both monoclonal and oligoclonal B-cell proliferations. These findings provide evidence for the evolution of EBV-induced polyclonal activation of B cells to oligoclonal B-cell proliferation and finally to monoclonal B-cell lymphoma.

Complexes prepared from protein A and human serum, IgG, or Fc gamma fragments: characterization by immunochemical analysis of ultracentrifugation fractions and studies on their interconversion

Protein A of Staphylococcus aureus is an Fc receptor for IgG that has been used as a therapeutic reagent to treat cancer in humans and experimental animals. We used ultracentrifugation combined with analysis of isolated fractions by radioimmunoprecipitation and competitive radioimmunoassay with chicken antibodies that bind free protein A or protein A in complexes but do bind free immunoglobulin reagents to localize and characterize the types of complexes formed with different molar ratios of 125I-protein A and human 131I-IgG alone or in serum, and 131I-Fc gamma fragments. This approach offers a distinct advantage over direct counting of radioactivity in the fractions because resolution of complexes and free reagents is much improved. With excess 131I-IgG or 131I-Fc, all the 125I-protein A is present only in complexes that contained 4 molecules of immunoglobulin reagent and 2 molecules of protein A (4:2 complexes), whereas with excess 125I-protein A the stoichiometry of the complexes was 1:1. We have also shown the preformed 4:2 and 1:1 complexes will interconvert in the presence of added excess protein A or IgG, respectively, and that fresh IgG will exchange with IgG or Fc gamma in preformed complexes. Because protein A has been found to elute from an immobilized reagent used in serotherapy of human cancer and is present in a large excess of IgG, the 4:2 complexes may play an active role in the tumoricidal or toxic reactions observed.

Protein phosphorylation in anti-actin IgG and [(IgG)2protein A]2 complex-stimulated L cells

Phosphorylation of cellular proteins was stimulated in a dose-dependent manner by the surface binding of IgG antibodies to antigens on L cells. Most prominent among the phosphorylated cellular proteins were Mr = 115,000, 93,000, 58,000, 38,000, and 33,000 proteins. Stimulation of protein phosphorylation was maximal at 48 hr of incubation and was preceeded by maximal stimulated uridine incorporation into RNA (0-24 hr) and thymidine incorporation into DNA (24-48 hr), and followed by maximal stimulated cell proliferation occurring at 72 hr (P less than 0.001 for all differences). Modification of the ligand IgG molecule by formation of complexes with protein A (PA) altered the stimulation patterns of protein phosphorylation: [(IgG)2(PA)]2, Mr = 716,000, enhanced and (IgG)(PA), Mr = 200,000, inhibited phosphorylation. The nature of the cell surface antigen(s) was partially clarified by the demonstration that affinity-purified antibodies to cytoskeletal proteins (principally a surface actin molecule) accounted for a significant part of the stimulation effect. Thus, perturbation of the L-cell membrane by certain molecular forms of anti-actin IgG antibody produces a transmembrane signal resulting in an orderly series of metabolic events including enhanced protein phosphorylation at 48 hr occurring just prior to enhanced cell growth.

Cytotoxic anti-T cell antibodies in children with juvenile rheumatoid arthritis

The object of this investigation was to determine the prevalence of anti-T cell antibodies in 66 children with various connective tissue diseases. Anti-T cell antibodies were found in 43/44 juvenile rheumatoid arthritis (JRA) patients (mean cytotoxicity 15.0%) and in 10/10 children with systemic lupus erythematosus (mean cytotoxicity 20.0%), but in only 1/15 normal controls and in none of 12 children with other arthritides. There was no significant difference in mean percent cytotoxicity among the JRA subclasses. In the JRA patients, the percent cytotoxicity was positively correlated with the erythrocyte sedimentation rate (P = 0.01), but not with the presence or absence of rheumatoid factor, antinuclear antibodies, or immune complexes. The sera of 3 JRA patients repeatedly inhibited the stimulation of normal lymphocytes by mitogens and antigens by 47-99% (measured by the incorporation of 3H-thymidine into DNA) when added to the culture system in the first 24 hours; normal sera did not. Sera from patients with JRA have increased reactivity with mitogen-activated lymphocytes and T cells compared with unstimulated cells as determined by flow cytometry. The expression of the "JRA antigen" requires protein synthesis but not DNA synthesis or cell division. We conclude that the majority of patients with active JRA have cytotoxic anti-T cell antibodies and that in selected patients, these antibodies may play a role in regulation of the immune response.

PGE1 not PGF2 alpha reverses the anti-actin antibody stimulation of protein phosphorylation and DNA synthesis in L cells

The effects of prostaglandins E1 and F2 alpha upon the anti-actin antibody-induced stimulation of DNA synthesis and protein phosphorylation were studied in L cells. This system was previously shown by us to exhibit a rapid turnover of arachidonic acid in phospholipids which was inhibited by non-toxic concentrations of indomethacin, suggesting participation of cyclooxygenase-derived prostaglandins (Lipids 19:239, 1984). Prostaglandin E1 in a dose dependent manner selectively inhibited both protein phosphorylation and DNA synthesis in anti-actin antibody-stimulated cells. Prostaglandin F2 alpha was without effect. Indomethacin also produced a dose related inhibition of the antibody stimulation of protein phosphorylation and DNA synthesis. We conclude that prostaglandins, possibly derived from liberated arachidonic acid, play an important regulatory role in the stimulatory signal conveyed to L cells by perturbing antibody ligands.

[(IgG)2 protein A]2 complex stimulates cytosine arabinoside incorporation into DNA and inhibits L cell proliferation

A Mr = 716 000 complex, [(IgG)2 Protein A]2, formed when Protein A is mixed with a molar excess of IgG anti-L cell antibody, augmented [3H]thymidine incorporation in DNA and growth of a murine transformed L cell line. It was also possible to augment the incorporation of [3H]cytosine arabinoside (2.3-fold) in DNA by the binding of this complex to L cells. A synergistic inhibition of L cell proliferation was produced using the complex and certain concentrations of cytosine arabinoside. By binding the complex to L cells, a 5-fold lower concentration of cytosine arabinoside (0.050 microgram/ml) was as effective in inhibiting cell replication as the higher dose of the drug (0.25 microgram/ml) with cells bound by IgG antibody alone, and a 20-fold lower concentration compared to the effects of the drug itself (1.0 microgram/ml). Addition of 10 microM thymidine to the complex permitted the use of an even lower dose of cytosine arabinoside (0.004 microgram/ml) for inhibition of cell growth. Thymidine caused this effect by producing an even greater incorporation of drug into the DNA of complex-stimulated cells. Thus, by stimulating the cell with the immune [(IgG)2 Protein A]2 complex it was possible to stimulate uptake of a chemotherapeutic nucleoside and selectively inhibit cell replication at non-toxic doses of nucleoside.

Immunoregulation in an isolated 12-year-old boy with congenital severe combined immunodeficiency

We report the evaluation of in vitro immunoregulation in a 12-year-old untreated boy with severe combined immunodeficiency (SCID). Severely hypogammaglobulinemic, the patient was incapable of a specific antibody response to either natural substances or administered antigens. Ficoll-Hypaque-isolated peripheral blood mononuclear cells (MNL) from the patient failed to respond to pokeweed mitogen (PWM) with the normal increment in immunoglobulin-secreting cells, as measured by a reverse hemolytic plaque assay. Since the patient was lymphopenic, his MNL were relatively enriched for monocytes (range = 51-81%). Removal of phagocytic cells or the addition of unrelated irradiated helper T lymphocytes resulted in enhanced, but still suboptimal response to PWM, suggesting some intrinsic defect in B lymphocyte function. Co-culture of patient MNL with normal MNL resulted in marked suppression (12% of predicted) of PWM-induced Ig-secreting cells. Suppressor activity was unaffected by prior irradiation of patient MNL, but was substantially reversed (99% of predicted) by removal of his phagocytic cells, whereas the combination of the two procedures further reversed suppression (184% of predicted). The patient's MNL consistently demonstrated subnormal percentages of T3+ and T4+ cells and subnormal to low normal percentages of T8+ cells. These data suggest both an intrinsic defect in B lymphocyte function, and a relative excess of monocytes which could further inhibit Ig secretion by B lymphocytes. Natural killer (NK) cell function was characterized by normal target cell binding by NK cells but severely depressed NK cell cytotoxicity.

Correlation between covalent attachment of C3 and calcium uptake in antibody-stimulated L cells

The nature of C3 binding to cell surfaces was examined in L cells treated with antibody and complement, immunological reagents which we have previously shown to be capable of producing stimulation of several important cellular processes. In the presence of serums containing C3 and under experimental conditions where complement activation could take place, selective binding of C3 to antibody treated L cells was observed (maximum 1.1 X 10(6) C3 molecules per cell). Under similar conditions there was a C3 dependent increased calcium uptake (3.4 pmol) by antibody treated cells. Purified C3 was able to selectively restore C3 binding to cells treated with serum depleted of C3 through C9. C7-deficient serum was almost as good a source of activated C3 as its normal serum counterpart. Strong chemical nucleophiles such as salicylhydroxamic acid, which are capable of covalently coupling to the labile internal thiolester of C3, prevented the binding of C3 to cells. We conclude that C3 is covalently bound to antibody and complement treated L cells, possibly serving as an important signal in subsequent enhancement of phospholipid metabolism, DNA synthesis, and cell growth.

Enhanced N-acylation of palmitic acid in sphingomyelin of antibody-stimulated L cells

Metabolism of sphingomyelin was stimulated in a fibroblast-like transformed cell line, L-929, when the cells were incubated with antibodies of a specific rabbit antiserum. The cells responded with an increased incorporation of [3H] palmitic acid into sphingomyelin. The stimulated uptake of palmitic acid into sphingomyelin can not be explained by simple mass increases in cellular phospholipids but probably represents a selective N-acyl group turnover. Palmitic acid composed only 7.5 percent of the acyl substituents, as assessed by gas-liquid chromatographic analysis, but [3H] palmitic acid was incorporated at a two-fold higher level into the acyl position than into the long chain base precursor (sphingosine). Since it is known that palmitic acid is the predominant fatty acid forming sphingosine, this represents a considerable selection for N-acyl group turnover. Another saturated fatty acid, stearic acid, which was over twice as abundant constituently was incorporated at a much lower rate when the cells were stimulated. Thus palmitic acid was observed to be selectively turning over in a manner suggestive of acylation-reacylation cycles observed with other classes of phospholipids.

Antibody to immunoselected L-cell antigens mimics stimulating activity of antibody to whole L cells

A heterogeneous IgG antibody raised in rabbits in response to injections of whole L cells was used to identify and select relevant antigens in a nonionic detergent extract of L cells prelabeled with [35S]methionine by means of immunoprecipitation and immunoaffinity chromatography. When analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the immunoprecipitate and immunoeluate contained far fewer protein bands than the whole cell extract but selectively retained a 42,000-MW protein species. In response to injections of the immunoprecipitate, rabbits produced a new antiserum which reacted predominantly with the 42,000-MW protein when reacted with L-cell proteins separated by sodium dodecyl sulfate-gel electrophoresis and transferred to nitrocellulose paper by the Western blot technique. The new antiserum (raised to the immunoprecipitate) and the original antiserum (raised to whole cells) were equipotent in stimulating calcium transport, phospholipid metabolism, and DNA synthesis in L cells. Binding of the IgG fractions of the two antisera displayed identical high affinity binding to L-cell surface antigens, with the same average association constant of 1.5 X 10(6) M-1. These studies have shown that an antiserum raised to whole L cells has a much narrower reactive spectrum with L-cell membrane antigens than might be imagined and has identified a 42,000-MW membrane protein as an important immunogen which itself elicits a potent immune response resulting in an antibody capable of mimicking the cell stimulatory properties of the original antiserum.

IgG-protein A complexes modulate thymidine incorporation into DNA of antibody and complement-stimulated cells

Incubation of protein A (PA) and molar excess of whole rabbit immune IgG in solution favored the formation of high m.w. complexes with the molecular formula of [(IgG)2(PA)]2, which enhanced the incorporation of [3H]thymidine ([3H]dThd) into DNA of L cells, especially in the presence of rabbit or human complement (C). In contrast, complexes with the molecular formula (IgG)(PA), formed by incubation of IgG with molar excess of PA, failed to enhance, or inhibited, the incorporation of [3H]dThd into cells treated with immune IgG alone or with C present, respectively. Concanavalin A (Con A), which is known to bind to critical exposed oligosaccharide structures present in the Fc region of IgG in the [(IgG)2(PA)]2 complexes, reversed the enhancement of [3H]dThd incorporation, and alpha-methyl mannoside, but not D-galactose, inhibited the Con A reversal. The [(IgG)2(PA)]2 complexes efficiently activated the C cascade, caused significantly higher levels of aggregation of cells, and increased the binding of immune IgG to the cells when compared to the (IgG)(PA) complexes. Both types of complexes, isolated by sucrose density ultracentrifugation, were precipitable in a radioimmunoassay with chicken anti-PA antibodies and were capable of binding to intact L cells.

IgG-protein A complexes modulate thymidine incorporation into DNA of antibody and complement-stimulated cells

Incubation of protein A (PA) and molar excess of whole rabbit immune IgG in solution favored the formation of high m.w. complexes with the molecular formula of [(IgG)2(PA)]2, which enhanced the incorporation of [3H]thymidine ([3H]dThd) into DNA of L cells, especially in the presence of rabbit or human complement (C). In contrast, complexes with the molecular formula (IgG)(PA), formed by incubation of IgG with molar excess of PA, failed to enhance, or inhibited, the incorporation of [3H]dThd into cells treated with immune IgG alone or with C present, respectively. Concanavalin A (Con A), which is known to bind to critical exposed oligosaccharide structures present in the Fc region of IgG in the [(IgG)2(PA)]2 complexes, reversed the enhancement of [3H]dThd incorporation, and alpha-methyl mannoside, but not D-galactose, inhibited the Con A reversal. The [(IgG)2(PA)]2 complexes efficiently activated the C cascade, caused significantly higher levels of aggregation of cells, and increased the binding of immune IgG to the cells when compared to the (IgG)(PA) complexes. Both types of complexes, isolated by sucrose density ultracentrifugation, were precipitable in a radioimmunoassay with chicken anti-PA antibodies and were capable of binding to intact L cells.

Incorporation of fatty acids into phospholipids in L cells stimulated by antibody

Binding antibodies to surface membranes stimulated incorporation of fatty acids (FA) into phospholipids of L cells. Antibodies stimulated at least a 3.4-fold greater incorporation of arachidonic acid into phosphatidylinositol than into any other class of phospholipid when compared on a molar basis (p less than 0.003). This enhanced incorporation was selective, depending on the character of the FA, because antibodies stimulated the incorporation of arachidonic acid at least 2.4-fold more than oleic acid, palmitic acid or stearic acid (p less than 0.001). Surprisingly, an antibody-stimulated incorporation of palmitic acid into sphingomyelin (SM) was at least 2.2-fold greater than that into any other class of phospholipid (p less than 0.001) and the antibody-stimulated incorporation of palmitic acid into SM was at least 60-fold greater than that of arachidonic acid, stearic or oleic acid (p less than 0.001). Nontoxic doses of ethylenediamine tetraacetic acid (EDTA), dexamethasone, 4-bromophenacylbromide and indomethacin inhibited the antibody-stimulated incorporation of arachidonic acid into cellular phospholipids, principally phosphatidylinositol (PI), and similarly inhibited the antibody stimulation of DNA synthesis. We conclude that when antibody binds to surface antigens on L cells, a rapid and selective incorporation of fatty acids into certain cellular phospholipids occurs, possibly mediated by calcium-dependent phospholipases. Degradation products of arachidonic acid, i.e., prostaglandins, may be important in these antibody stimulation events, as well. These early changes in phospholipid metabolism may serve as an important signal or mechanism for the subsequent stimulation of DNA synthesis in L cells.

Tumoricidal response following perfusion over immobilized protein A: identification of immunoglobulin oligomers in serum after perfusion and their partial characterization

Previously, we showed that perfusion of plasma from hosts bearing breast adenocarcinoma over immobilized staphylococcal protein A resulted in objective tumor regressions. In the present study, sera perfused in vitro over immobilized staphylococcal protein A were analyzed by physicochemical and immunochemical methods to characterize newly formed products. Sera from normal and breast adenocarcinoma-bearing dogs showed increased levels of C1q-binding IgG after perfusion over a strain of staphylococcus that is protein A rich (Cowan I), but not protein A deficient (Woods 46). C1q binding levels were also increased in normal and tumor-bearing canine or human sera which were perfused over purified protein A immobilized in collodion charcoal (PACC), and this increase was localized in sucrose density gradient fractions ranging from 7S to 19S. Polyacrylamide gel electrophoresis analysis of the high-molecular-weight fraction in postperfusion canine sera, isolated by G-200 fractionation and immunoaffinity chromatography, showed predominantly heavy and light immunoglobulin chains of canine IgG. Furthermore, protein A was released from PACC after perfusion with serum or solutions containing IgG or albumin from humans, dogs, and chickens. After serum perfusion over PACC, protein A was identified in the effluent by additional studies as follows: (a) polyacrylamide gel electrophoresis analysis showed that eluted 125I-protein A comigrated with the protein A marker; (b) postperfusion C1q-binding complexes, isolated by gel filtration under dissociating conditions and affinity chromatography on IgG-Sepharose showed a single precipitin band with normal human (protein A reactive) but not chicken (protein A unreactive) serum. Protein A released from PACC which appeared in postperfusion sera was associated with immunoglobulins in macromolecular complexes since (a) eluted 125I-protein A was largely (NH4)2SO4 and polyethylene glycol precipitable, whereas free protein A was not, and it sedimented in sucrose density gradient fractions distributed beyond the 7S marker, compared to free protein A which localized below 7S; (b) radiolabeled protein A eluting from PACC after serum perfusion showed 8-fold greater binding to C1q-coated tubes compared to free protein A; and (c) increased C1q-binding IgG in postperfusion sucrose density gradient fractions corresponded to the appearance of protein A in parallel gradient fractions.(ABSTRACT TRUNCATED AT 400 WORDS)

Modulation of metabolism of cytosine arabinoside in L cells by antibody and complement

Complement modulated the metabolic conversion of cytosine arabinoside into its nucleotide and nucleic acid derivatives in L cells by augmenting the biphasic effect (inhibitory/stimulatory) of anti-L cell antibody. Antibody in the absence of complement affected both the total cellular pool of cytosine arabinoside (containing the nucleotide and nucleic (DNA) acid derivatives) and the acid-insoluble pool (containing the DNA derivative). Addition of complement in high concentrations inhibited and, in low concentrations, stimulated the incorporation of cytosine arabinoside into DNA of antibody stimulated L cells. At the point of maximum stimulation of cytosine arabinoside incorporation into DNA, there was a pronounced decrease in the size of the total cellular pool with the result that 75% of the total pool of cytosine arabinoside was due to its incorporation into DNA. Simultaneous measurements upon cytosine arabinoside and thymidine or deoxycytidine metabolism were made; the effects of antibody and complement appeared to be quite similar with all three nucleosides, with the exception that all thymidine and deoxycytidine taken up into the cells was incorporated into DNA. Addition of exogenous thymidine (up to 100 microM produced the same enhanced incorporation of [3H]Ara-C and [14H]dCyd into control cells that was observed in antibody and complement stimulated cells. Measurement of deoxycytidine kinase activity in cell-free extracts of cell cultures stimulated by antibody, however, did not reveal enhanced enzymatic activity due to stimulated enzyme synthesis, but, rather indicated that antibody and complement altered the intracellular concentrations of nucleotides which affected the interaction of cytosine arabinoside with deoxycytidine kinase in intact cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Tumoricidal response induced by cytosine arabinoside after plasma perfusion over protein A

In dogs with spontaneous mammary adenocarcinomas, a single nontoxic infusion of cytosine arabinoside after extracorporeal perfusion of plasms over immobilized protein A resulted in a necrotizing response rapid in onset and specific for tumorous tissue. Gross tumoricidal reactions 12 hours after this combined treatment exceeded the algebraic sum of responses to cytosine arabinoside and protein A perfusion treatments alone in the same dogs, implying a synergistic effect between the two. The magnitude, rapidity, and specificity of the tumoricidal response after the combined treatment suggests that it may be an effective chemimmunotherapeutic approach to breast adenocarcinoma.

Fatal cytomegalovirus bronchiolitis in a patient with Nezelof's syndrome

A 4-year-old girl who had received a fetal thymus gland by intraperitoneal transplantation 41 months previously sustained acute, fatal bronchiolitis due to culture-proven cytomegalovirus despite the fact that a specific antibody response to this organism was detected. While the thymic transplantation had increased the number of circulating T lymphocytes and had permitted immune sensitization to delayed-hypersensitivity skin test antigens, there was still an incomplete state of T lymphocyte function. In particular, isolated lymphocytes failed to respond to stimulation with phytohemagglutinin at several concentrations and, more important, the pathologic examination demonstrated a severe anatomic deficiency of lymphoid tissue associated with T lymphocyte function. The unusual infection that caused the death of this child emphasized the necessity of acquiring sufficient T lymphocyte function in immunologic reconstitution attempts.