Search

The association between T3 and the T cell antigen receptor was examined using the T3 bearing T cell leukemic line Jurkat. A monoclonal antibody, C305, was produced, which reacted with idiotypic-like determinants expressed on Jurkat. The molecule with which this antibody reacted was a disulfide-linked heterodimer of 90 kD, composed of polypeptides of 42 and 54 kD. Thus, C305 reacted with a molecule with characteristics of the putative T cell antigen receptor described by others. A series of mutants of Jurkat, induced with ethyl methane sulfonate or radiation, was selected for T3 or antigen receptor negativity. In every instance, there was a concomitant loss of both T3 and the antigen receptor as assessed by quantitative absorption, indirect immunofluorescence, and antibody plus complement-mediated cytotoxicity. The absence of antigen receptor molecules was confirmed on diagonal gels, excluding the possibility that conformational changes of the antigen receptor on such T3-negative mutants were responsible for the failure of such mutants to react with C305. Moreover, in a mutant that expressed a marked decrease in the level of T3 expression, there was a comparable decrease in the expression of antigen receptor determinants. These results suggest that there is an obligate requirement for the coexpression of T3 and the T cell antigen receptor. Furthermore, attempts to activate such mutants with the lectin phytohemagglutinin suggested that the expression of T3 and/or the antigen receptor was required for activation of these cells.

In September 2005, the University of Texas Medical Branch at Galveston (UTMB) was threatened by Hurricane Rita, a category five storm. Abandoning its historic practice of clearing the hospital of all but the sickest patients, UTMB rapidly organized and conducted the first total evacuation in its 114-year history. The authors report how this was accomplished and lessons learned. Specific factors were crucial for success, including identifying an incident commander with sole authority to make decisions, developing and communicating a set of guiding principles, setting patient safety as our top priority, establishing an incident command center that consolidated vital institutional functions, avoiding delays in deciding to evacuate, identifying strategic partners, selecting essential personnel who would not be distracted by personal concerns during the emergency, and conducting periodic trial runs of emergency preparedness. Complex demands for communication were not met as well as was hoped. Technical problems were encountered with some communication devices that proved inoperable; trial runs would have probably revealed these problems in advance. Also, in-transit communication could be improved-not always knowing which patients were where, what vehicles were mired in stalled traffic, and what relocations occurred impeded optimal communication with patients' family members. Finally, a system ensuring that the recipients of UTMB's electronic records had the proper software to receive them would have facilitated communication and helped record keeping. The authors encourage physicians, as essential members of the health care team, to become better prepared to respond to disasters.

Faced with explosive growth in its prison population and a legal mandate to improve medical care for incarcerated offenders, the state of Texas implemented a novel correctional managed health care program in 1994. The organizational structure of the program is based on a series of contractual relationships between the state prison system, 2 of the state's academic medical centers, and a separate governing body composed of 9 appointed members, which include 5 physicians. All medical, dental, and psychiatric care for more than 145,000 offenders, incarcerated under the jurisdiction of the Texas Department of Criminal Justice, is provided by the University of Texas Medical Branch and Texas Tech University Health Sciences Center. The health delivery system is composed of several levels of care, including primary ambulatory care clinics in each prison unit, 16 infirmaries at strategic locations throughout the state, several regional medical facilities, and a dedicated prison hospital with a full range of services. Specialized treatment programs have been established at various units for patients with chronic conditions, such as hypertension, diabetes mellitus, major psychiatric disorders, hepatitis, and human immunodeficiency virus infection. Significant improvements in health outcomes have occurred since the managed care program was established.

Objective: To determine the gender-based career obstacles for women in an academic department of medicine and to report the interventions to correct such obstacles (resulting from the evaluation) and the results of these interventions., Design: Intervention study, before-after trial, with assessment of faculty concerns and perceived change through structured, self-administered questionnaires., Setting: The Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Md., Participants: Full-time faculty., Interventions: Multifaceted intervention from 1990 through 1995 to correct gender-based career obstacles reported by women faculty, including problem identification, leadership, and education of faculty, and interventions to improve faculty development, mentoring, and rewards and to reduce isolation and structural career impediments., Main Outcome Measures: Retention and promotion of deserving women faculty, salary equity, quality of mentoring, decreased isolation from information and colleagues, integration of women faculty into the scientific community, and decreased manifestations of gender bias., Results: Junior women were retained and promoted, reversing previous experience, with a 550% increase in the number of women at the associate professor rank over 5 years (from 4 in 1990 to 26 in 1995). Interim 3-year follow-up showed a 183% increase in the proportion of women faculty who expected they would still be in academic medicine in 10 years (from 23% [7/30] in 1990 to 65% [30/46] in 1993). One half to two thirds of women faculty reported improvements in timeliness of promotions, manifestations of gender bias, access to information needed for faculty development, isolation, and salary equity. Men also reported improvements in these areas., Conclusions: The outcomes reported here indicate that it is possible to make substantive improvements in the development of women's careers, that an institutional strategy to this end can be successful in retaining women in academic medicine, and that such interventions are likely to benefit all faculty. Long-term interventions appear essential.

Peripheral blood mononuclear cells (PMC), isolated by density gradient techniques with Ficoll-Hypaque, contain T- and B-lymphocytes and monocytes. Aryl hydrocarbon hydroxylase (AHH) activity was measured in PMC subfractions consisting of T-lymphocyte-enriched, T-lymphocyte-depleted, and monocyte-depleted populations. The T-cell-enriched populations consistently showed enhancement of AHH activity with both the fluorometric and radiometric technique when compared to the total PMC population. This enhanced AHH activity was observed when T-cell-enriched populations were isolated either before or after 96 hr of lymphocyte culture, by the sheep red blood cell rosette method, or by the nylon wool column technique before lymphocyte culture. T-cell-depleted populations (B-cell enriched) obtained by sheep red blood cell rosette method had diminished AHH activity. Monocytes were shown to contribute to the total PMC AHH activity through an indirect technique by first depleting the monocytes from PMC with the carbonyl iron method. The monocyte-depleted populations had less AHH activity than did the total PMC population after both 24 and 96 hr of culture. The greatest amount of AHH activity was present in PMC populations with their native number of monocytes when cultured for 96 hr in the presence of mitogens.

The ability of monocytes/macrophages to regulate various aspects of immunologic responses may in part depend on their release of soluble substances such as prostaglandins. Using quantitative gas-liquid chromatography/mass spectrometry, prostaglandin E2 was found to be the major prostaglandin synthesized in culture by human peripheral blood monocytes. Subjecting these cells to discontinuous density gradient fractionation demonstrated significant differences in the synthesis of prostaglandins E2 and E1 among the resulting monocyte subpopulations.

The human T cell line Jurkat is a useful model of regulated T cell activation. After in vitro treatment of Jurkat with phytohemagglutinin (PHA) and phorbol ester (PMA), RNA transcripts of both interleukin 2 (IL 2) and interferon-gamma (IFN-gamma) appear, followed by secretion of both biologically active lymphokines. Employing the nuclear run-on technology, we first confirmed that the expression of both lymphokines after T cell activation is regulated at the transcriptional level. By using the recombinant approach of DNase I hypersensitivity mapping, we had previously localized a structurally unique, lymphocyte-specific genomic domain in the first intron of the human IFN-gamma gene that correlated with the transcriptional potential of that gene. By using several T cell lines that differ in their inducible expression of IFN-gamma, we have now localized several additional structural domains within the human IFN-gamma gene that appear to be coordinately involved in regulating expression. These include: a distal 5' flanking region site also seen only in T lymphocytes that can express the gene, a proximal, promoter-associated site that appears only after PHA/PMA-mediated IFN-gamma induction, and a second intronic site seen only in T cells whose IFN-gamma gene is selectively inactive. Collectively, our data suggest that T cell activation is accompanied by transcriptional level induction of lymphokine gene expression. In the case of IFN-gamma, T cell nuclei possess specific structural domains within the gene itself that seem to participate both positively and negatively in activation-mediated regulatory events.

Antibodies against the T3-antigen receptor complex can activate the human T cell line, Jurkat, to produce interleukin 2 (2-5). This activation is initiated by a receptor-mediated increase in the concentration of free cytoplasmic calcium ions [Ca2+]i (3, 4). In this communication, we investigate the mechanism by which the receptor complex increases [Ca2+ )i in Jurkat cells. The initial receptor-mediated change in [Ca2+]i can occur when extracellular Ca2+ is depleted by EGTA. Perturbation of the T cell antigen receptor, therefore, generates a signal which mobilizes Ca2+ from intracellular stores. As inositol trisphosphate appears to function as such a signal for certain hormone receptors, we measured the levels of inositol trisphosphate and of the other inositol phosphate compounds in Jurkat. Antibodies to either the antigen receptor heterodimer or T3 determinants result in marked elevations of all three inositol phosphates. These changes in inositol phosphates are not secondary to the receptor-mediated increases in [Ca2+]i as demonstrated by the inability of the Ca2+ ionophore, ionomycin, to affect the levels of any of these compounds. In concentrations between 0.1 and 1 microM, purified inositol trisphosphate releases Ca2+ from permeabilized Jurkat cells. Taken together, these data indicate that, during activation, perturbation of the T3-antigen receptor complex generates inositol trisphosphate. This compound functions as an intracellular signal to release Ca2+ from intracellular stores, leading to increases in [Ca2+]i.

The bare lymphocyte syndrome is a disorder in which class I histocompatibility antigens fail to be expressed normally on the surface of lymphocytes. Utilizing complementary DNA probes for both beta 2-microglobulin and class I genes, the molecular basis for this syndrome was investigated in a family with two siblings exhibiting the bare lymphocyte syndrome. Southern blot analysis demonstrated no gross internal defect in either class I or beta 2-microglobulin genes. Northern blot analysis of class I and beta 2-microglobulin messenger RNAs also revealed no qualitative difference between affected and unaffected family members. In contrast, quantitation of both class I and beta 2-microglobulin transcripts demonstrated each to be decreased in patients when compared to controls. Moreover, the decrease in both transcripts was coordinate. These results suggest that the bare lymphocyte syndrome may represent a pretranslational regulatory defect of both class I and beta 2-microglobulin gene expression.

The autologous mixed lymphocyte reaction (AMLR) represents the proliferation of T cells in response to signals from autologous non-T cells. Fractionation of the non-T population into B enriched and macrophage enriched cells demonstrated that both could serve as effective stimulator cells in the AMLR. Cytolytic treatment of both populations with a macrophage specific, monoclonal antibody abrogated stimulation of the macrophage but not the B cell population. Utilizing a series of negative selection procedures - cytolysis with T cell specific monoclonal antibody, metabolic suicide with 5-bromo-2-deoxyuridine (brdU) and light - it could be demonstrated that T cells responding to autologous macrophage were distinct from those responsive to autologous B cells. Studies of the AMLR reactivity to B cells and macrophage in a small number of patients with active systemic lupus erythematosus (SLE) demonstrated that although reactivity to both populations was diminished, the response to autologous B cells was reduced more than the response to autologous macrophage. These studies suggest that the AMLR represents the sum reactivities of two responder T cells. Moreover, they suggest that a relatively selective deficiency in only one of these cells may occur in SLE.

Utilizing somatic cell hybridization, we have developed a monoclonal antibody that interacts only with cells of the monocyte/macrophage (M phi) line and not with other myeloid or lymphoid cells. This antibody detects a 120,000-dalton determinant present on 37 +/- 2.8% of the peripheral blood M phi from several (HLA-DR)-disparate individuals and only depicts a subpopulation (approximately 30%) of HLA-DR-bearing M phi from any single subject. Cytolytic removal of this subpopulation of HLA-DR-bearing cells markedly diminished antigen-induced T cell reactivity, a deficiency that can be reconstituted with autologous M phi but not with either their soluble products containing lymphocyte-activating factor or with intact HLA-DR-disparate M phi. Whereas M phi bearing both the 120,000-dalton determinant and HLA-DR serve as effective stimulators for autologous mixed lymphocyte reactions. M phi bearing only HLA-DR determinants do not. However, this latter population of M phi can stimulate proliferation among alloreactive T cells. These studies indicate that the Mac-120 monoclonal antibody detects a subpopulation of HLA-DR-bearing M phi that is required for the genetically restricted presentation of conventional antigen to reactive T cells. Within the M phi population, these Mac-120+ cells constitute the most effective stimulators for autologous mixed lymphocyte reactions.

Fifty patients with late-onset idiopathic immunoglobulin deficiency were studied and the frequency of various clinical associations and complications was observed. Men and women were equally affected, although the age at onset in men peaked in the third decade whereas it was more uniformly distributed in women. Sinobronchopulmonary infections were common and were caused by Haemophilus influenzae. Diplococcus pneumoniae, Streptococcus pyogenes and Staphylococcus aureus: bronchiectasis occurred in 28 per cent. Thirty patients (60 per cent) had diarrhea, which was often associated with steatorrhea, giardiasis, achlorhydria, abnormal Schilling tests and morphologic abnormalities on small bowel biopsy specimens, including nodular lymphoid hyperplasia; three patients had pernicious anemia. In the 20 patients without diarrhea these abnormalities were not observed except for giardiasis in one patient and achlorhydria in two patients. Cholelithiasis occurred in both groups in about a third of the patients tested. A high degree of susceptibility to neoplasia was noted. Thyroid abnormalities, including primary hypothyroidism and Graves' disease, were observed in six patients. Additional occasional findings were vitiligo, keratoconjunctivitis sicca and arthritis. Splenomegaly occurred in 14 (28 per cent) patients. The percentage of B lymphocytes in the blood was determined in 10 patients; it was normal or slightly decreased in eight patients and low in two patients.

Circulating antibodies to native and denatured types I and II human and bovine collagens were assayed in patients with rheumatoid arthritis (RA), patients with other rheumatic diseases, and normal individuals. A subgroup of this population was also assayed for reactivity with typing reagents which detect determinants (MT and HLA-DR) present in human immune response gene products. The mean titers of antibodies to each collagen tested were not significantly higher in RA patients when compared with patients who had other rheumatic diseases. Although both MT3 and MT4 were significantly associated with RA, there was no significant association between the anticollagen antibodies and any MT type or HLA-DR4. These studies raise a question concerning the role of collagen antibodies in the pathogenesis of RA and suggest that genes distinct from those coding for HLA-DR may play a role in the expression of the disease.

Human immune response genes can be divided into three distinct loci, each of which codes for three distinct families of Ia molecules: HLA-SB, HLA-DC, and HLA-DR. The tissue distribution and function of only one of these Ia molecules, HLA-DR, has been thoroughly studied. Using monoclonal antibodies, we examined the display of HLA-DR and HLA-DC molecules by adherent, human peripheral blood monocytes. The results of these studies demonstrate that although all human peripheral blood monocytes display easily detectable HLA-DR molecules, only 50% display easily detectable HLA-DC molecules. Separation of peripheral blood monocytes into HLA-DC+ and HLA-DC- cells demonstrates that each population displays an equivalent density of HLA-DR molecules. Therefore, on the basis of differences in their display of these two Ia molecules, adherent peripheral blood monocytes can be divided into two broad populations: HLA-DR+, HLA-DC+, and HLA-DR+, HLA-DC-. Despite the dis-coordinate display of these Ia antigens, the expression of both HLA-DR and HLA-DC can be regulated by a common signal, gamma interferon (IFN-gamma). Incubation of monocytes for 96 h in autologous serum leads to a marked decrease in the expression of both HLA-DR and HLA-DC. Addition of recombinant IFN-gamma to the cultures leads to reexpression of both HLA-DR and HLA-DC to levels comparable to those seen in fresh monocytes. In addition, although IFN-gamma does not modulate all monocyte surface markers, it can be demonstrated to modulate expression of one marker, MAC 120, in a manner similar to that observed for Ia antigens. These studies demonstrate that among human peripheral blood monocytes, the distribution of the Ia molecule, HLA-DC, is not coordinate with that of HLA-DR, although both respond to the same regulatory signal.

Monoclonal antibodies to the T-cell antigen receptor can mimic the effects of antigen and induce cellular activation. In this article john Imboden and his colleagues report on the use of these antibodies as probes to study the mechanism by which the antigen receptor initiates activation. They also describe the critical role of cytoplasmic free calcium in transmembrane signal transduction by the T-cell antigen receptor., (Copyright © 1985. Published by Elsevier B.V.)

Progressive liver injury in chronic active liver disease is usually associated with elevation of serum immunoglobulin levels. However, the role of immunoglobulins in the pathogenesis of this disease is still obscure. We report here the case of a 41-year-old man with hypogammaglobulinemia since at least 1964 in whom chronic active liver disease later developed. From 1954 he had had frequent respiratory tract infections, and these continued, along with diarrhea, despite regular gamma-globulin therapy. Studies in 1969 showed absent serum IgA and IgM and an abnormally low level of IgG. In 1974, liver enzyme abnormalities were recorded and a diagnosis of chronic active liver disease was made. A liver biopsy showed cirrhosis with active hepatitis. Lymphocyte function studies revealed that the T cells suppressed B-cell maturation and production of immunoglobulins. He was treated with azathioprine and prednisone, and this therapy has been associated with a decrease in both the elevation in liver enzymes and the frequency of infections. This case suggests that liver cell injury in chronic active liver disease is independent of the elevation of immunoglobulins and that immunosuppressive therapy may be well tolerated by patients with hypogammaglobulinemia.

Peripheral blood mononuclear cells from patients with either Crohn's disease or ulcerative colitis (collectively referred to as inflammatory bowel disease) are cytotoxic in vitro for isologous or allogeneic colonic epithelial cells. Utilizing the ability of thymus-derived (T) lymphocytes to bind sheep red blood cells to their surface and the property of bone marrow-derived (B) lymphocytes to display easily detectable surface immunoglobulin determinants, the cytoxicity of these lymphocyte subpopulations was tested. The results indicate that the mononuclear cell required for the lysis of colonic epithelium was not included within the bulk of T or B lymphocytes. Indeed, enrichment for cytotoxicity correlated best with enrichment for a mononuclear cell population lacking classical T or B markers. Additionally, mononuclear cells specifically adhering to plastic petri dishes coated with heat-aggregated immunoglobulin, and thus presumably bearing a surface Fc receptor, were enriched in their cytotoxicity. Alternatively, cells not adhering to aggregated Ig-coated petri dishes were relatively depleted of cytotoxicity. The implications of these findings as they relate to possible interactions between cellular and humoral immune mechanisms as a pathogenic mechanism for the colonic inflammatory process noted in patients with inflammatory bowel disease are discussed.

The association of positive antinuclear antibodies with the clinical and hemodynamic features of 43 patients with primary pulmonary hypertension and 16 patients with secondary pulmonary hypertension was investigated. Each patient had determinations of antinuclear antibodies using a KB cell substrate immunofluorescent test. Of the patients with primary pulmonary hypertension, 40% had positive antinuclear antibodies at titers of 1:80 dilutions or greater. There were no differences between patients with primary pulmonary hypertension and positive antinuclear antibodies compared with those with negative antinuclear antibodies in relation to clinical or hemodynamic status. A 6% incidence rate of antinuclear antibodies was found in patients with secondary pulmonary hypertension, similar to that in the normal population. The clinical, hemodynamic, serologic and histologic similarity between patients with primary pulmonary hypertension and those with unexplained pulmonary hypertension associated with collagen vascular disorders suggests that primary pulmonary hypertension in some patients may represent a collagen vascular disease confined to the lungs. The frequency of positive antinuclear antibody tests would place primary pulmonary hypertension between rheumatoid arthritis and scleroderma in the spectrum of collagen vascular diseases. Further studies are necessary, however, before one might expect that immunosuppressive therapy would be beneficial to these patients.

Immunization of mice with a supraoptimal dose of sheep red blood cells (SRBC) results in splenic T cell populations capable of specifically suppressing recipients' plaque forming cell (PFC) and delayed-type hypersensitivity (DTH) responses to SRBC when tested in an adoptive transfer system. By localization on discontinuous bovine serum albumin (BSA) gradients and relative sensitivity to Cytoxan, two distinct T cell subpopulations suppressing DTH reactivity were identified. One population could not be distinguished from T cells capable of inhibiting direct and indirect PFC responses. However, another population appeared quite distinct and capable of inhibiting DTH, but not PFC responses.

Several culture conditions and media were studied in an effort to establish long-term cultures of murine lymphoid cells from blood and thymus. Cultures vessels included small glass bottles and rubber-stoppered tubes. Media such as Roswell Park Memorial Institute 1640, 1700, 1701, 1715, GEM 1717, NCTC, fetal calf and horse serum supplements, and conditioned medium were tried. Lymphoid cells in mouse leukocyte cultures survived as long as eight months before dying out. However, lymphoid cells in thymus cell cultures, strarted and maintained with GEM 1717 medium with 20% fetal calf serum supplementation, gave rise to cell lines that continued to yield subcultures for more than 2 years. Mcroscopic examination of thymus cell subcultures revealed lymphoid and thymic epighelioid cells. Tumorigenicity studies of one cell line were negative. Chromosomal preparations of this cell line often contained near-normal karyotypes but were complicated by the presence of binucleated cells. Live cell fluorescent antibody assays for surface theta-antigen and immunoglobulin revealed immunoglobulin-negative cells possessing barely detectable theta determinants. Functional assays for thymus-derived lymphoid cell activity suggested that these cells were mitogen responsive and weakly reactive in one-way mixed lymphocyte culture. On the basis of this evidence it was sugguested that these cells represent a class of T-cells (thymus-derived lymphocytes) that have all but lost theta antigen, possibly due to prolonged culture.

T cells capable of proliferating in response to signals from autologous cells can be demonstrated in normal peripheral blood. The stimulating cell is contained among populations enriched in B cells, "null" cells, and monocytes, but not among populations enriched in T cells. Density gradient fractionation indicated that the autologous reactive T cell may represent a subpopulation of cells responsive in allogeneic mixed lymphocyte cultures. This was confirmed by negative selection (BUDR and light) experiments which also indicated that the "autologous" stimulus can be mediated by at least some allogeneic cells. In a portion of patients with active systemic lupus erythematosus, autologous reactivity was reversibly blocked. Prior incubation of either responding T or stimulator cells at 37 degrees C restored this reactivity.

The genetic control of the murine immune response to denatured beef type II collagen was examined in an antigen-presenting cell-dependent T cell proliferation assay. It was found that the response to collagen is under the control of H-2-linked Ir genes, possibly operating at the level of the antigen-presenting macrophage. Utilizing in vitro cross-stimulation with synthetic collagen-like polypeptides, the data suggest that the antigenic determinants stimulating collagen immune T cells are more dependent on primary amino acid sequence and less on conformation. The implications of such findings for Ir gene specificity and other related immunologic functions is discussed.

The immunologic responses, both cell-mediated and humoral, to exogenous antigens reflect a crucial balance between extrinsic forces which can either augment or suppress the reactivity of T and B effector cells. It is probable that similar immunoregulatory influences play a key role in maintaining tolerance to some self-antigens. Thus, despite the presence of cells potentially capable of reacting to autologous antigens, lack of autoimmunity might reflect either an absence of amplifying or a preponderance of suppressive immunoregulatory forces. Within this framework, data obtained indicating aberrances of immunoregulation in patients with systemic lupus erythematosus are discussed, specifically as the aberrances may be causally related to the autoimmune nature of this disease.