Use of cellular fatty acid analysis to characterize commercial brands of Bacillus thuringiensis var. israelensis

The cellular fatty acid composition of Bacillus thuringiensis var. israelensis (B.t.i.) from 5 commercial brands (Vectobac, Acrobe, Skeetal, Bactimos and Teknar), as well as of the current International Standard for B.t.i. (IPS 82), was determined using a Hewlett-Packard Microbial Identification System. The original strain of B.t.i., B.t. var. kurstaki, B.t. var. thuringiensis, B.t. var. morrisoni and Bacillus sphaericus strain 2362 were used as outgroups. Acrobe, Bactimos, Teknar, Vectobac and IPS 82 consisted of the same strain. Skeetal represented a different strain than the other commercially produced B.t.i. Our results indicate that cellular fatty acid analysis can be used to distinguish among the forms of B.t.i. produced by various manufacturers.

Effects of IL-12 on the generation of cytotoxic activity in human CD8+ T lymphocytes

We have studied the effects of human rIL-12 on the proliferation and generation of cytotoxic activity in human CTL precursors. Purified human blood CD8+ T lymphocytes were stimulated overnight with immobilized alpha-CD3 and cultured 3 to 4 additional days under various conditions. The addition of IL-12 resulted in a marked (10- to 20-fold), dose-dependent, augmentation of cytotoxicity per cell with a smaller (2-fold) increase in cell number. IL-12 augmentation of proliferation and cytotoxicity of CD8+ T cells was not inhibited by a mAb to the p55 subunit of the IL-2 receptor (alpha-Tac) at a concentration sufficient to block the activity of exogenously added IL-2, indicating that the activity of IL-12 did not require IL-2. Addition of IL-12 at the time of alpha-CD3 activation or 1 day later was highly effective at augmenting cytotoxicity, whereas delayed addition of IL-12 (day 2 or 3) resulted in a smaller increase in CTL activity with no increase in cell number. IL-12 at all doses tested synergized with low dose IL-2 in inducing the proliferation and differentiation of CD8+ T cells. The synergistic effect was not blocked by adding neutralizing serum to IFN-gamma. In contrast to this synergistic effect, IL-12 significantly inhibited the proliferation observed in the presence of higher concentrations of IL-2 (4,500 and 13,500 pg/ml). An inhibitory effect of IL-12 was also observed when IL-12 was added to CD8+ T lymphocytes 3 days subsequent to activation with alpha-CD3 and IL-2. This broad set of potent effects of IL-12 on CD8+ T cell responses suggests that IL-12 may play an important immunoregulatory role on CTL development in vivo and may be a useful tool for manipulating this process in vivo for investigational and immunotherapeutic purposes.

Interleukin (IL)-2 and IL-3 induce distinct but overlapping responses in murine IL-3-dependent 32D cells transduced with human IL-2 receptor beta chain: involvement of tyrosine kinase(s) other than p56lck

We have established IL-3-dependent 32D myeloid progenitor cells stably expressing the human IL-2 receptor beta chain (IL-2R beta). Whereas parental 32D cells proliferated only in response to IL-3, the transduced cells also proliferated in response to IL-2. Transduced cells expressed high- and intermediate-affinity IL-2Rs, resulting from expression of human IL-2R beta and murine IL-2R alpha chain (IL-2R alpha). IL-2 induced phenotypic changes not induced by IL-3, including the upregulated expression of endogenous murine IL-2R alpha and IL-2R beta and an increase in cell size. Therefore, the transduced IL-2R beta was not merely coupling with the IL-3 signaling pathway. IL-3 augmented several IL-2-induced responses including the up-regulation of IL-2R alpha. Both IL-2- and IL-3-induced proliferation and IL-2 induced IL-2R alpha expression were inhibited by the tyrosine kinase inhibitor herbimycin A. Thus, both IL-2- and IL-3-mediated effects required tyrosine kinase activity. The identity of the tyrosine kinase(s) mediating the IL-2 signals in these cells is not known but cannot be p56lck, a tyrosine kinase found in T cells, since 32D-IL-2R beta cells do not express p56lck.

Risk factors associated with transmissible gastroenteritis in swine

Commercial production data base records from 2 Illinois farms, on which epizootic or enzootic transmissible gastroenteritis (TGE) was experienced, were accessed for an epidemiologic study. Risk factors investigated were sow parity, source of sows, location of farrowing crates, and breeding practices. At farm 1, an epizootic was experienced; at farm 2, an epizootic of TGE followed by enzootic TGE was experienced. Initially, crude risk ratios were calculated for these risk factors, and the crude risk ratios were subsequently adjusted for confounders and interactions, using multiple logistic regression techniques. After adjustment, parity-3 sows were 2.3 times more likely to have litters with TGE than were sows of all other parities on farm 1, and parity-1 sows were 2.6 times more likely to have litters that experienced TGE than were sows of all other parities on farm 2. A single boar on each farm was linked to increased likelihood of a sow's litter contracting epizootic TGE on each farm. Enzootic TGE was maintained by the periodic influx of outside-source gilts on farm 2; these gilts were 2.2 times more likely to have litters with TGE than were sows derived from farm 2. Sows housed in farrowing crates located under the cold air inlet of farm 2 were 1.7 times as likely as sows located in other rows to have litters with enzootic TGE.

Haptoglobin and ceruloplasmin as determinants of inflammation in dogs

Assay procedures for determining serum haptoglobin concentration and ceruloplasmin oxidase activity in dogs were validated, and reference values were established. Serum haptoglobin concentration is reported as milligrams per deciliter of cyanmethemoglobin binding capacity, whereas serum ceruloplasmin oxidase activity was determined by use of p-phenylenediamine as substrate. Both assays were used to analyze serum samples from 288 dogs. In each dog's case record, clinical history and final diagnosis were evaluated to determine whether the dog had an inflammatory condition. Complete blood cell counts were performed in 265 dogs, using simultaneously collected blood samples. Plasma fibrinogen concentration was determined for 161 dogs. A positive correlation (P less than 0.01) for serum haptoglobin concentration and for ceruloplasmin oxidase activity, compared with WBC counts, segmented neutrophil and band neutrophil counts, and plasma fibrinogen concentration. Ceruloplasmin oxidase activity and haptoglobin concentration were up to 6 times more sensitive than fibrinogen concentration or leukocyte counts in detecting inflammation. Specificity of ceruloplasmin oxidase activity was comparable to fibrinogen concentration and leukocyte counts, whereas haptoglobin concentration was found to be slightly less specific. Specificity of haptoglobin concentration improved slightly (from 0.82 to 0.88) when dogs with a history of glucocorticoid administration were excluded from analysis. Predictive value of a negative test result (haptoglobin concentration less than 125 mg/dl; ceruloplasmin oxidase activity less than 20 IU/L) and predictive value of a positive test result for haptoglobin concentration and ceruloplasmin activity were comparable to or better than fibrinogen concentration or various oxidase leukocyte counts in detection of inflammation in a variety of disease conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-2 toxicity

Because of the ability of interleukin-2 (IL-2) to support the proliferation and activation of numerous types of immunocompetent cells and to support the survival of adoptively transferred lymphocytes, there has been considerable interest in its use in the immunotherapy of malignancies. While studies to date have indicated that IL-2 has activity against some malignancies, considerable toxicity has also been observed. Careful prescreening and selection of patients and appropriate management of toxicity can minimize adverse outcomes. Studies of IL-2 effects have provided intriguing evidence of interactions of the immune/cytokine system with the neuroendocrine, cardiovascular, and other systems. Studies in animal models have demonstrated the central role of an intact immune system in mediating many toxicities of IL-2. Several adverse effects of IL-2 appear to be mediated by other cytokines whose production is induced by IL-2. Studies into the pathogenesis and manifestations of IL-2 toxicity have offered the hope of developing less toxic approaches to IL-2 therapy. Several lessons from the IL-2 experience are likely to be applicable in the clinical development of other cytokines.

Regulation of human cytotoxic T lymphocyte development by IL-7

The effects of IL-7 on the generation of human CTL in alloantigen-, virus-, and lectin-stimulated systems were examined. Addition of IL-7 at the onset of cultures resulted in marked (up to 80-fold) augmentation of cytotoxicity accompanied by smaller (1.5- to 4-fold) increases in total lymphocyte number. Studies of CTL development in purified lectin-stimulated CD8+ T cell populations demonstrated that IL-7 could act directly on the CD8+ lymphocyte subset to augment cytotoxicity. In MLC, the IL-7-induced enhancement of cytotoxicity was found to be mediated primarily by the CD8+ subpopulation of lymphocytes. Late addition of IL-7 (day 5 of 7) resulted in an increase in cytolytic activity that was associated with little or no increase in total or activated CD8+ lymphocyte number indicating that IL-7 may act as a differentiation factor for human CTL. A role for endogenous IL-7 in CTL development was suggested by the observation that addition of neutralizing antiserum to IL-7 to MLC at initiation (or 5 days thereafter) resulted in decreased levels of cytotoxicity. These results indicate that IL-7 can exert major up-regulatory effects on human CTL development and suggest that these effects are both proliferative and differentiative.

Regulation of human cytotoxic T lymphocyte development by IL-7

The effects of IL-7 on the generation of human CTL in alloantigen-, virus-, and lectin-stimulated systems were examined. Addition of IL-7 at the onset of cultures resulted in marked (up to 80-fold) augmentation of cytotoxicity accompanied by smaller (1.5- to 4-fold) increases in total lymphocyte number. Studies of CTL development in purified lectin-stimulated CD8+ T cell populations demonstrated that IL-7 could act directly on the CD8+ lymphocyte subset to augment cytotoxicity. In MLC, the IL-7-induced enhancement of cytotoxicity was found to be mediated primarily by the CD8+ subpopulation of lymphocytes. Late addition of IL-7 (day 5 of 7) resulted in an increase in cytolytic activity that was associated with little or no increase in total or activated CD8+ lymphocyte number indicating that IL-7 may act as a differentiation factor for human CTL. A role for endogenous IL-7 in CTL development was suggested by the observation that addition of neutralizing antiserum to IL-7 to MLC at initiation (or 5 days thereafter) resulted in decreased levels of cytotoxicity. These results indicate that IL-7 can exert major up-regulatory effects on human CTL development and suggest that these effects are both proliferative and differentiative.

A bioassay for the measurement of human interleukin-4

We have developed a bioassay for human IL-4 based upon its ability to upregulate CD23 (low affinity IgE receptor) expression. Ramos, a B lymphocyte line derived from a Burkitt lymphoma, was repetitively subcloned yielding a clone, Ramos.G6.C10, which is several fold more sensitive to this effect of IL-4. In microtiter plates cells were cultured for 48 h in the presence of dilutions of recombinant human IL-4 or samples, and then stained with murine anti-human CD23 and goat anti-mouse IgG-FITC. IL-4 induced an eight-fold increase (60 channel shift) in fluorescence intensity as measured by flow cytometry. Significant effects were observed at an IL-4 concentration of 50-100 pg/ml and increased with concentrations up to 800 pg/ml. Inter- and intra-assay coefficients of variation were 10% and 11% respectively. The bioassay showed good specificity for IL-4; however, tumor necrosis factors alpha and beta, at optimal concentrations, gave readings barely at the threshold of detection.

Expression of high-affinity IL-4 receptors on murine tumour infiltrating lymphocytes and their up-regulation by IL-2

Since interleukin-2 (IL-2) and IL-4 act in concert to support the development of cytotoxic T lymphocytes (CTL) and the generation of antigen-specific tumour infiltrating lymphocytes (TIL), we investigated the interaction of these cytokines with an established TIL line. TIL proliferated in an additive fashion in response to suboptimal concentrations of IL-2 and various concentrations of IL-4. TIL possessed high-affinity IL-4 receptors whether cultured in recombinant IL-2 (rIL-2) or rIL-4, but cells cultured in rIL-2 had higher numbers of IL-4 receptors than cells cultured in rIL-4. When TIL were cultured in increasing concentrations of rIL-2, a dose-dependent enhancement in IL-4 receptor number was observed. The maximum induction of IL-4 receptor expression was achieved by 4 hr of incubation with rIL-2 and was completely blocked by cycloheximide. Other cytokines, such as rIL-1, recombinant tumour necrosis factor (rTNF), recombinant interferon-alpha (rIFN-alpha) and rIFN-gamma, had no effect on IL-4 receptor number. rIL-2 also up-regulated IL-4 receptors on CTLL-2, a murine CTL line. These data indicate that high-affinity IL-4 receptors exist on murine TIL and they can be up-regulated by IL-2. Our observation that IL-2 up-regulates IL-4 receptor may help explain the additive effects of these lymphokines on the proliferation of TIL and other cell lines. It may also help explain their co-operative effects on the generation of antigen-specific TIL and the differentiation of CTL.

Effect of cyclosporin A and ionophores on the intracellular pH of lymphocytes as measured by flow cytometry

Because of the known importance of pHi changes on the biology of cells, we have investigated the effect of CsA, the clinically important immunomodulator, on the pHi of resting mouse spleen and human peripheral blood lymphocytes. We have found that pharmacological doses (0.8 microM) of CsA caused no change in the pHi in these cells. Similarly, the Ca2+ ionophore, A23187, up to 5 microns concentration, had no effect on the pHi of these cells, in contrast to previous reports. However, higher doses of CsA (2.4-8.0 microM) did change the pHi transiently or permanently. These results were obtained with flow cytometric measurements of fluorescence intensity of the pH-sensitive dye, BCECF.

IL-4 (B cell-stimulatory factor 1) regulates multiple aspects of influenza virus-specific cell-mediated immunity

The effect of endogenous and exogenous IL-4 on the generation of influenza virus-specific cell-mediated immunity was examined. When added at the onset of the culture, IL-4 augmented both cluster of differentiation (CD)8+ lymphoproliferation and MHC-restricted, influenza virus-specific cytotoxicity. When added 5 or 6 days after initiation of cultures, IL-4 was highly effective at augmenting cytotoxicity, whereas no augmentation of proliferation was observed. This disassociation of the effect of IL-4 on lymphoproliferation and cytotoxicity indicated that IL-4 was providing a late signal in CTL generation. Studied at the level of CTL precursor maturation in microcultures, IL-4 was found not to increase cytotoxicity but to be required, in some cases, for the generation of cytotoxicity. Endogenous IL-4 production was observed and demonstrated to be important because neutralizing antiserum to IL-4 suppressed CTL development. In contrast to the effects of IL-4 when added later to the cultures, pulsing the lymphocytes with IL-4 before, or shortly after, exposure to antigen resulted in suppression of the CTL response. These results indicate that IL-4 has differentiative, proliferative, and suppressive effects on cell-mediated immune responses.

IL-4 (B cell-stimulatory factor 1) regulates multiple aspects of influenza virus-specific cell-mediated immunity

The effect of endogenous and exogenous IL-4 on the generation of influenza virus-specific cell-mediated immunity was examined. When added at the onset of the culture, IL-4 augmented both cluster of differentiation (CD)8+ lymphoproliferation and MHC-restricted, influenza virus-specific cytotoxicity. When added 5 or 6 days after initiation of cultures, IL-4 was highly effective at augmenting cytotoxicity, whereas no augmentation of proliferation was observed. This disassociation of the effect of IL-4 on lymphoproliferation and cytotoxicity indicated that IL-4 was providing a late signal in CTL generation. Studied at the level of CTL precursor maturation in microcultures, IL-4 was found not to increase cytotoxicity but to be required, in some cases, for the generation of cytotoxicity. Endogenous IL-4 production was observed and demonstrated to be important because neutralizing antiserum to IL-4 suppressed CTL development. In contrast to the effects of IL-4 when added later to the cultures, pulsing the lymphocytes with IL-4 before, or shortly after, exposure to antigen resulted in suppression of the CTL response. These results indicate that IL-4 has differentiative, proliferative, and suppressive effects on cell-mediated immune responses.

Limiting-dilution analysis of human CTL differentiation. Requirement for a lymphokine-mediated differentiation signal

The induction of human influenza virus-specific memory cytotoxic T lymphocytes (CTL) from CTL precursors (CTLp) was investigated using limiting-dilution cultures and cell lines. Differentiation of maximal numbers of CTLp in limiting-dilution cultures required at least three signals: antigen stimulation, interleukin-2 (IL-2), and a differentiation factor distinct from IL-2. Antigen-specific CTLp proliferated in response to antigen stimulation and recombinant DNA-derived IL-2, but often failed to acquire cytolytic activity unless conditioned medium (CM) from mitogen-stimulated peripheral blood mononuclear cell (PBMC) cultures was added to the cultures. Temporal analysis of the requirement for CM indicated that it was providing a late signal for CTLp differentiation. This analysis was confirmed by developing CTLp cell lines, which were found to proliferate in response to IL-2 and antigen but not to exhibit influenza virus-specific cytotoxicity until CM was added.

Modulation of class I and class II histocompatibility antigens on human T cell lines by IFN-gamma

IFN-gamma is an immunomodulatory agent which is known to induce or enhance the expression of class II histocompatibility Ag (Ia Ag) on many lymphoid cells and cell lines of diverse origin. However, we have observed that IFN-gamma did not induce the expression of Ia Ag on Ia- human T cell lines. Neither did IFN-gamma enhance the expression of Ia Ag on Ia+ T cells. However, IFN-gamma was able to enhance the expression of class I histocompatibility Ag (HLA-A,B,C Ag) on a number of the T cell lines tested. Experiments with 125I-labeled IFN-gamma showed a relatively small degree of specific binding to these T cell lines. More extensive studies on two of the T cell lines demonstrated 1000 and 2600 IFN-gamma binding receptor sites/cell and binding affinities of 4.0 X 10(-10) M and 7.3 X 10(-10) M. Thus, although IFN-gamma can bind to human T cell lines and enhance class I histocompatibility Ag on these cells, IFN-gamma alone does not appear to regulate expression of class II histocompatibility Ag on T cell lines.

Modulation of class I and class II histocompatibility antigens on human T cell lines by IFN-gamma

IFN-gamma is an immunomodulatory agent which is known to induce or enhance the expression of class II histocompatibility Ag (Ia Ag) on many lymphoid cells and cell lines of diverse origin. However, we have observed that IFN-gamma did not induce the expression of Ia Ag on Ia- human T cell lines. Neither did IFN-gamma enhance the expression of Ia Ag on Ia+ T cells. However, IFN-gamma was able to enhance the expression of class I histocompatibility Ag (HLA-A,B,C Ag) on a number of the T cell lines tested. Experiments with 125I-labeled IFN-gamma showed a relatively small degree of specific binding to these T cell lines. More extensive studies on two of the T cell lines demonstrated 1000 and 2600 IFN-gamma binding receptor sites/cell and binding affinities of 4.0 X 10(-10) M and 7.3 X 10(-10) M. Thus, although IFN-gamma can bind to human T cell lines and enhance class I histocompatibility Ag on these cells, IFN-gamma alone does not appear to regulate expression of class II histocompatibility Ag on T cell lines.

The human interleukin 2 receptor beta chain (p70). Direct identification, partial purification, and patterns of expression on peripheral blood mononuclear cells

IL-2 binds to high- and low-affinity receptors on activated T cells. The high-affinity receptor was hypothesized to consist of the noncovalent association between the alpha chain (IL-2-R-alpha, p55) and a beta chain (IL-2-R-beta, p70), whereas the low-affinity receptor consists of p55 without p70. We now directly identify p70 as a 65-77-kD glycoprotein doublet. Preparative quantities of the IL-2/p70 complex have been isolated. Further, we demonstrate that p70 is the principal IL-2 binding protein on both resting CD4+ and CD8+ T cells and that both p70 and p55 can be induced on normal B cells and monocytes.

Effects of interferon-gamma on the activation of human T lymphocytes

The role of interferon (IFN)-gamma in the activation of human T cells was investigated. Addition of IFN-gamma to mixed-lymphocyte cultures (MLC) augmented both the proliferation and the development of T-cell-mediated cytotoxicity. IFN-gamma also augmented the early expression on CD8+ but not CD4+ lymphocytes of IL-2 receptor alpha chain (Tac antigen) and Class II major histocompatibility antigen (HLA-DR). This effect synergized with that caused by interleukin 2 and was not observed with IFN-alpha. The addition of neutralizing antibody against IFN-gamma to MLC suppressed the development of cytotoxicity and proliferation and the expression of activation antigens on CD8+ cells. In experiments in which highly purified CD8+ T cells were activated with cell-free stimuli, IFN-gamma slightly but significantly augmented proliferation, antibody to IFN-gamma suppressed proliferation, and excess IFN-gamma reversed this suppression. It is concluded that (i) IFN-gamma augmented activation of T cells in human MLC, (ii) IFN-gamma exerted effects directly on T cells, and (iii) IFN-gamma preferentially augmented CD8+ cell activation.

The IL-2 receptor beta chain (p70): role in mediating signals for LAK, NK, and proliferative activities

Interleukin-2 (IL-2) induces cytolytic activity and proliferation of human blood lymphocytes. Yet, prior to activation, these cells do not express IL-2 receptors recognized by monoclonal antibodies to the Tac antigen. A novel glycoprotein (IL-2R beta), identified on several lymphocytoid cell lines, has the ability to bind IL-2 alone and to associate with Tac antigen (IL-2R alpha) to form high-affinity IL-2 receptors. It is now reported that IL-2R beta is expressed on both circulating T lymphocytes and large granular lymphocytes in quantities approximately proportional to their responsiveness to IL-2. Studies of the responses of these cells to IL-2 suggest that IL-2R beta mediates the initial phase of induction of lymphokine activated killer (LAK), natural killer (NK), and proliferative activities. Subsequently, IL-2R alpha is induced and functional high-affinity IL-2 receptors are expressed.

Premenstrual tension syndrome symptom clusters. Statistical evaluation of the subsyndromes

Premenstrual symptoms were evaluated in a group of women with severe premenstrual tension syndrome. Factor analysis was performed in order to establish the nature of symptom clusters in this sample. Similar to clinical observations reported on before, the results revealed two distinct clusters of emotional/behavioral symptoms and two of physical symptoms.

Differential effects of interferon-alpha and interferon-gamma on interleukin 1 secretion by monocytes

We examined the effect of interferon (IFN)-alpha and IFN-gamma on the ability of human monocytes to secrete interleukin 1 (IL 1). IFN-alpha directly induced IL 1 secretion by monocytes. IFN-gamma did not induce any IL 1. IFN-gamma-stimulated monocyte supernatants were also negative for pyrogenic activity. However, IFN-gamma greatly enhanced the amount of IL 1 secreted when monocytes were stimulated by lipopolysaccharide or Staphylococcus aureus, even at concentrations which by themselves did not induce IL 1. IFN-alpha did not enhance IL 1 secretion induced by other stimuli. IFN-gamma enhanced IL 1 secretion by priming monocytes to be more sensitive to an IL 1-inducing stimulus. However, IFN-gamma does not enhance IL 1 induced by all stimuli, because there was no enhancement of IL 1 induced by PMA. Thus, IFN-alpha and IFN-gamma have very distinct roles in the induction and enhancement of IL 1 by monocytes.

Differential effects of interferon-alpha and interferon-gamma on interleukin 1 secretion by monocytes

We examined the effect of interferon (IFN)-alpha and IFN-gamma on the ability of human monocytes to secrete interleukin 1 (IL 1). IFN-alpha directly induced IL 1 secretion by monocytes. IFN-gamma did not induce any IL 1. IFN-gamma-stimulated monocyte supernatants were also negative for pyrogenic activity. However, IFN-gamma greatly enhanced the amount of IL 1 secreted when monocytes were stimulated by lipopolysaccharide or Staphylococcus aureus, even at concentrations which by themselves did not induce IL 1. IFN-alpha did not enhance IL 1 secretion induced by other stimuli. IFN-gamma enhanced IL 1 secretion by priming monocytes to be more sensitive to an IL 1-inducing stimulus. However, IFN-gamma does not enhance IL 1 induced by all stimuli, because there was no enhancement of IL 1 induced by PMA. Thus, IFN-alpha and IFN-gamma have very distinct roles in the induction and enhancement of IL 1 by monocytes.

Demonstration of T-cell dysfunction during acute toxoplasma infection

Mice were infected with the virulent RH and the relatively avirulent C56 strains of Toxoplasma gondii (TG). The concanavalin A (Con A)-stimulated lymphoproliferative response of these animals and interleukin-2 (IL-2) production by their lymphocytes were assessed 3 and 6 days postinfection. The proliferative response of splenocytes (SC) and T-enriched cells from all infected groups was significantly (P less than 0.05-0.005) depressed. Partial removal of macrophages (m phi) or addition of indomethacin had no effect on the depressed proliferative response of SC from mice infected with the RH strain of TG for 6 days (RH6), and only partially improved that from the other infected groups. IL-2 production of T-enriched cells, obtained by scrupulously removing m phi using sequential adherence of SC to plastic and nylon wool, was markedly decreased in all infected mice. These data indicate that both m phi and T cells are involved in the immunodepression in toxoplasmosis. Except for the RH6 group, the depressed lymphoproliferative responses of all infected groups were entirely reconstituted by exogenous IL-2, but their peak response never reached that of the control group. Therefore, the decreased lymphoproliferation could not be explained solely by a defect in IL-2 production. The proliferative response of the RH6 lymphocytes, in the presence of Con A, was significantly lower than without Con A at each IL-2 concentration added. This suggests the presence of an active suppressor factor inducible by Con A. The RH strain of TG caused a greater degree of immunodepression than the C56 strain, suggesting an association between the virulence of different strains of TG with their ability to immunosuppress.

Comparison of depressed and nondepressed women with severe premenstrual tension syndrome

There is a need to better understand the relationship between premenstrual tension syndrome (PMS) and premenstrual depression. This research was designed to determine if severely depressed women experience a different kind of premenstrual dysfunction than nondepressed PMS patients. The nature and severity of premenstrual symptoms in both groups were evaluated and compared. The severely depressed women were found to have higher PMS scores, but did not differ from the nondepressed group in selection or ranking of symptoms. Depression appeared to influence the patient's perception and rating of symptoms, but the underlying premenstrual dysfunction was identical.

Mechanisms of T-cell functional deficiency in the acquired immunodeficiency syndrome

Cell-mediated immune responses to cytomegalovirus infections were studied to define mechanisms for deficient effector T-cell responses in patients with the acquired immunodeficiency syndrome (AIDS). Progressive cytomegalovirus infection is common in such patients and is accompanied by a failure to develop HLA-restricted cytotoxic T-cell responses. The mechanism for the cytotoxic T-cell deficiency is presumably the basis for susceptibility to opportunistic infections. Precursors to these effector cells circulate in the peripheral blood of patients, but maturation of these cells into cytotoxic T cells is arrested during an interleukin-2-dependent phase. Production of interleukin-2 by lymphocytes from patients with AIDS is deficient because sera from these patients contain an inhibitor of interleukin-2 production. Excess suppressor cell activity does not appear to account for this deficient production. Studies of the source of the serum inhibitor should provide insights into the pathogenesis of AIDS and possible leads for effective treatment.

Sera from patients with the acquired immunodeficiency syndrome inhibit production of interleukin-2 by normal lymphocytes

We studied the effects of sera from patients with the acquired immunodeficiency syndrome (AIDS) on interleukin-2 (IL-2) production to help elucidate the mechanism of immunodeficiency. Compared with sera from healthy controls, sera from AIDS patients suppressed phytohemagglutinin (PHA)-induced IL-2 production by normal blood mononuclear cells. Sera from homosexual contacts of AIDS patients and from adults with acute cytomegalovirus infection generally lacked this suppressive activity. The effect of the AIDS sera could not be attributed to absence of a stimulatory or nutritive factor, to inactivation of IL-2, to inhibition of the IL-2 assay, nor to increased turnover of IL-2. The suppressive effect of the sera was not mediated by radiosensitive or T8 antigen-bearing suppressor cells or by increased prostaglandin production or decreased interleukin-1 production. The sera acted directly on the groups of cells that produce IL-2, T cells and large granular lymphocytes; suppression occurred at an early, probably pretranslational, stage. When cells were incubated with AIDS sera and then washed, the suppressive effect persisted. The sera did not cause direct or complement-mediated cytotoxic effects on normal mononuclear cells nor did they suppress PHA-induced interferon production, nor proliferation of T lymphoblasts or lymphocyte lines. The suppressive effect was not mediated by interferon, cortisol, immunoglobulin G or M, or immune complexes. The activity was stable at pH 3, pH 10, and 60 degrees C; inactivated at 100 degrees C; and not ether extractable. Because IL-2 plays a central role in the development of many immune responses, the serum factor(s) that inhibits IL-2 production could contribute significantly to the immunodeficiency of AIDS.

Interleukin 2 therapy in infectious diseases: rationale and prospects

Clinical trials using interleukin 2 as a therapeutic immunomodulating agent in patients with acquired immunodeficiency syndrome have recently begun. In this article we present data from studies which indicate the ability of interleukin 2 in vitro to augment clinically important cytotoxic immune responses in lymphocytes from these patients. These studies provide both a rationale for the current trials and a model for evaluating the potential for use of interleukin 2 in other infectious diseases. We outline the types of infectious diseases in which interleukin 2 may prove to be useful and the therapeutic strategies in which it may play a role.

Use of interleukin-2 in patients with acquired immunodeficiency syndrome

Twelve patients with acquired immunodeficiency syndrome were treated with a natural product, highly purified human interleukin-2. Doses ranged from 250 to 250,000 units. No clinical responses were seen. Minimal toxicity was noted and consisted of mild prolongation of partial thromboplastin time and proteinuria. Immunologic changes during the study included a decrease in the number of circulating T8 lymphocytes, increased skin test reactivity, and a decline in serum immunoglobulin levels.

Interleukin 2 therapy in infectious diseases: rationale and prospects

Clinical trials using interleukin 2 as a therapeutic immunomodulating agent in patients with acquired immunodeficiency syndrome have recently begun. In this article we present data from studies which indicate the ability of interleukin 2 in vitro to augment clinically important cytotoxic immune responses in lymphocytes from these patients. These studies provide both a rationale for the current trials and a model for evaluating the potential for use of interleukin 2 in other infectious diseases. We outline the types of infectious diseases in which interleukin 2 may prove to be useful and the therapeutic strategies in which it may play a role.

Comparison of methods for quantitating antigen-specific immunoglobulin M antibody with a reverse enzyme-linked immunosorbent assay

We compared two methods for quantitating antigen-specific antibody by a reverse enzyme-linked immunosorbent assay. In the serial-dilution method, the result was determined to be the highest dilution of a serum yielding an absorbance above an established threshold. In the single-dilution method, the result was determined by comparing the absorbance yielded by the test serum at a standard dilution to that yielded by positive and negative reference sera at the same dilution. The results in the single-dilution method reflected the antigen-specific immunoglobulin M antibody activity as a proportion of total immunoglobulin M antibody in a serum, i.e., the immune load, whereas the results in the serial-dilution method reflected the absolute concentration of antigen-specific immunoglobulin M antibody activity. Compared with results in the serial-dilution method, results in the single-dilution method had considerably greater reproducibility on a day-to-day basis and under various test conditions. The single-dilution method was more useful in discriminating between sera from patients in an early stage of clinical infection due to Toxoplasma gondii and sera from patients in a later stage of infection.

Circulating immune complexes in toxoplasmosis: detection and clinical correlates

The 125I-C1q binding test was employed to detect circulating immune complexes in serum of 27 subjects with acute toxoplasmosis. The subjects had no known underlying disease. Elevated C1q binding activity (C1q-BA) was found in the serum of each of three adults with the systemic febrile form of toxoplasmosis, seven of 19 patients with the lymphadenopathic form, and one of four infants with congenital infection. The patients with the systemic form of illness had significantly greater mean C1q-BA than did those with the lymphadenopathic form (P less than 0.001). In six episodes of symptomatic toxoplasmosis associated with elevated C1q-BA, follow-up sera were obtained after resolution of all signs and symptoms. Each of these sera showed normalization of C1q-BA. We conclude that immune complex like material is frequently present in the serum of patients with toxoplasmosis and parallels disease activity.