Biomedical subjects

J D Marshall

Publications and source records attributed to J D Marshall.

At least 37 records · Page 2Linked to original sources

PubMed1999

Single-dose pharmacokinetics of a pleconaril (VP63843) oral solution in children and adolescents. Pediatric Pharmacology Research Unit Network.

Pleconaril is an orally active, broad-spectrum antipicornaviral agent which demonstrates excellent penetration into the central nervous system, liver, and nasal epithelium. In view of the potential pediatric use of pleconaril, we conducted a single-dose, open-label study to characterize the pharmacokinetics of this antiviral agent in pediatric patients. Following an 8- to 10-h period of fasting, 18 children ranging in age from 2 to 12 years (7.5 +/- 3.1 years) received a single 5-mg/kg of body weight oral dose of pleconaril solution administered with a breakfast of age-appropriate composition. Repeated blood samples (n = 10) were obtained over 24 h postdose, and pleconaril was quantified from plasma by gas chromatography. Plasma drug concentration-time data for each subject were fitted to the curve by using a nonlinear, weighted (weight = 1/Ycalc) least-squares algorithm, and model-dependent pharmacokinetic parameters were determined from the polyexponential parameter estimates. Pleconaril was well tolerated by all subjects. A one-compartment open-model with first-order absorption best described the plasma pleconaril concentration-time profile in 13 of the subjects over a 24-h postdose period. Pleconaril pharmacokinetic parameters (means +/- standard deviations) for these 13 patients were as follows. The maximum concentration of the drug in serum (Cmax) was 1,272.5 +/- 622.1 ng/ml. The time to Cmax was 4.1 +/- 1.5 h, and the lag time was 0.75 +/- 0.56 h. The apparent absorption rate constant was 0.75 +/- 0.48 1/h, and the elimination rate constant was 0.16 +/- 0.07 1/h. The area under the concentration-time curve from 0 to 24 h was 8,131.15 +/- 3,411.82 ng.h/ml. The apparent total plasma clearance was 0.81 +/- 0.86 liters/h/kg, and the apparent steady-state volume of distribution was 4.68 +/- 2.02 liters/kg. The mean elimination half-life of pleconaril was 5.7 h. The mean plasma pleconaril concentrations at both 12 h (250.4 +/- 148.2 ng/ml) and 24 h (137.9 +/- 92.2 ng/ml) after the single 5-mg/kg oral dose in children were higher than that from in vitro studies reported to inhibit > 90% of nonpolio enterovirus serotypes (i.e., 70 ng/ml). Thus, our data support the evaluation of a 5-mg/kg twice-daily oral dose of pleconaril for therapeutic trials in pediatric patients with enteroviral infections.

Administration, Oral↗

PubMed1998

Human DCTN1: genomic structure and evaluation as a candidate for Alström syndrome.

The human dynactin 1 gene (DCTN1) is positioned on chromosome 2p13, the candidate region for various diseases including Alström syndrome, limb-girdle muscle dystrophy, and Miyoshi myopathy. Here, we report the exon-intron structure of DCTN1 along with characterization of the 5' upstream sequence and alternative splice variants previously identified by Tokito et al. (1996), Mol. Biol. Cell 7: 1167-1180). Knowledge of the genomic structure of DCTN1allowed us to design intronic primers necessary for analyzing mutations in families segregating for diseases linked to this gene. These primers were tested on a French Acadian kindred segregating for Alström syndrome. No mutations were observed within the coding region of DCTN1 in this family. However, the intronic primers should allow for the rapid amplification of the coding region for mutational analysis of additional Alström families and other diseases tightly linked to the DCTN1locus on chromosome 2p13.

Alternative Splicing↗

PubMed1998

Pharmacokinetics and pharmacodynamics of bumetanide in critically ill pediatric patients.

This prospective, open-label, clinical trial was conducted to describe the pharmacology of bumetanide in pediatric patients with edema. Nine infants, children, and young adults with edema who were selected for diuretic therapy were studied. After a brief baseline period, each patient received parenteral bumetanide 0.2 mg/kg divided into two equal doses and administered every 12 hours. Urine excretion rate, fractional and total excretion of Na+, Cl-, and K+, creatinine clearance, and plasma and urine concentrations of bumetanide were measured at multiple intervals after drug administration. Bumetanide caused significant increases in the excretion rate of urine and each measured electrolyte. Unexpectedly, creatinine clearance increased dramatically after each dose. Adverse effects, including hypokalemia and hypochloremic metabolic alkalosis, were evident by the end of the treatment period. The plasma pharmacokinetics of bumetanide revealed mean +/- standard deviation values for total clearance and apparent volume of distribution of 3.9 +/- 2.4 mL/min/kg and 0.74 +/- 0.54 L/kg, respectively. Patients excreted an average of 34% of each dose unchanged in the urine over 12 hours. Plasma concentrations of bumetanide accurately predicted several renal effects using a link model with similar pharmacodynamic parameters in each case. Parenteral bumetanide 0.1 mg/kg administered every 12 hours produced significant beneficial and adverse effects in these critically ill pediatric patients with edema. Pharmacokinetic parameters are similar to those previously reported for infants. Plasma concentrations of bumetanide can predict effect-compartment pharmacodynamics.

Adult↗

PubMed1997

Genealogy, natural history, and phenotype of Alström syndrome in a large Acadian kindred and three additional families.

We describe a large Acadian kindred including 8 Alstrom Syndrome (AS) patients, with an age range of 4 to 26 at the time of clinical assessment. The affected subjects come from 5 nuclear families within this kindred. The phenotype includes early childhood retinopathy, progressive sensorineural hearing loss, truncal obesity, and acanthosis nigricans. In addition, hyperinsulinemia and hypertriglyceridemia with normal cholesterol levels were observed in most affected individuals tested. Non-insulin dependent diabetes mellitus and growth retardation appear to be age-related manifestations that occur post-adolescence. Younger affected children are not overtly hyperglycemic and are normal or above average height for age. Although the AS patients in kindred 1 presumably carry the same mutation, many manifestations of the disease are variable. For example, of the 8 children in the Acadian kindred, 4 have scoliosis, 2 have had infantile cardiomyopathy, 2 are hypothyroid, 1 has had hepatic dysfunction and is hypertensive, and 4 have developed asthma. Seven subjects described in this kindred exhibit developmental delay. One additional manifestation not described widely in the literature, advanced bone age, was observed in all subjects tested. The clinical data from this large Acadian kindred, together with information obtained from 4 additional AS patients in 3 unrelated kindreds, confirm and extend clinical observations previously described. In addition, the Acadian kindred with multiple affected individuals, probably arising from a common founder, should allow for identification of the chromosomal localization of a gene causing AS.

Abnormalities, Multiple↗

PubMed1997

Priming with IL-4 and IL-13 during HIV-1 infection restores in vitro IL-12 production by mononuclear cells of HIV-infected patients.

The production of proinflammatory cytokines can be regulated by several factors that exert activating or inhibitory effects. IL-4, IL-10, IL-13, TGF-beta, and PGE2 have demonstrated a very wide range of potent macrophage-deactivating activities and, specifically, down-regulation of the production of many proinflammatory monokines. IL-12 plays a key role during immune response by providing a link between natural resistance and adaptive immunity. We and others have previously shown an impairment in IL-12 production by PBMC from HIV-1-infected individuals in response to various stimuli, but defining the mechanism responsible remains elusive. In this study, we observed that pretreatment of PBMC from patients with IL-4 or IL-13 for 24 h primes the cells for enhanced production of IL-12 in response to Staphylococcus aureus, and almost completely restores their deficient IL-12 production when compared with healthy controls. Although this priming effect was completely abrogated by IL-10 and PGE2, IL-10 was produced equivalently by untreated and IL-4- or IL-13-pretreated PBMC from both patients and controls. Additionally, indomethacin, which shuts off PGE2 synthesis, and cAMP-blocking reagents failed to restore or enhance IL-12 production. The priming effect of IL-4 and IL-13 is at the transcription level for both p40 and p35 genes. This complete restoration of IL-12 production by Th2-associated cytokines was unexpected in light of the mutually antagonistic roles of IL-12 and IL-4 in promoting Th1 or Th2 immune responses.

HIV Infections↗

PubMed1997

IL-15 enhances immune functions during HIV infection.

IL-15, a new cytokine primarily produced by macrophages, has been shown to exhibit several functional properties shared with IL-2. Treatment of PBMC from HIV-infected patients with IL-15 resulted in an increase in NK cell cytotoxicity to levels similar to those of untreated PBMC from healthy donors. This effect is independent of several well-characterized regulatory cytokines, as it is not prevented by Abs that neutralize IFNs, TNF-alpha, IL-2, or IL-12. Enhanced cytotoxicity was accompanied by a significant increase in expression of cytotoxic granules. IL-15 enhanced the proliferative ability in both controls and HIV-seropositive in response to mitogen and recall Ags. Although the addition of IL-15 has a preventive effect on the appearance of spontaneous cell death, this effect was not seen during mitogen-induced apoptosis. The production of IL-15 by PBMC from patients in response to Staphylococcus aureus Cowan strain 1 appeared heterogeneous and was not negatively regulated by cytokines that inhibited IL-12 production. No correlation was found between in vitro HIV infection and IL-15 production, as viral infection had no effect on the ability of monocytes to produce IL-15 in response to S. aureus. Interestingly IL-15 restored the deficient production of IL-12 by PBMC from HIV+ people and had no major effect on modulating viral expression in latently infected cell lines or PBMC from naturally infected people. Taken together, these results suggest a potent immunoregulatory role of IL-15 during HIV infection.

Adult↗

PubMed1997

Frequency and cytokine profile of HPRT mutant T cells in HIV-infected and healthy donors: implications for T cell proliferation in HIV disease.

It has been postulated that HIV-infected patients undergo an active production of virus and CD4+ T cell destruction from the early stages of the disease, and that an extensive postthymic expansion of CD4+ T cells prevents a precipitous decline in CD4+ T cell number. Based on the rebound of the CD4+ T cell number observed in patients undergoing antiretroviral therapy with protease inhibitors, it has been calculated that, on average, 5% of T cells are replaced every day in HIV-infected patients. To obtain an independent estimate of the recycling rate of T cells in the patients, we measured the frequency of cells carrying a loss-of-function mutation at the hypoxanthine guanine phosphoribosyl transferase (hprt) locus. Assuming a recycling rate of 5%/d, an accumulation of 2.6 mutations/10(6)/yr over the physiological accumulation was predicted. Indeed, we observed an elevated frequency of HPRT mutants in the CD4+ T cells of most patients with < 300 CD4+ T cells/mm3 of blood and in the CD8+ T cells of most patients with < 200 CD4+ T cells/mm3, consistent with an elevated and protracted increased division rate in both subsets. However, in earlier stages of the disease the mutant frequency in both CD4+ and CD8+ T cells was lower than in healthy controls. The cytokine production profile of most HPRT mutant CD4+ T cell clones from both healthy and HIV-infected patients was typical of T helper cells type 2 (high IL-4 and IL-10, low IFN-gamma), whereas the cytokine production pattern of wild-type clones was heterogeneous. The cytokine profile of CD8+ clones was indistinguishable between HPRT mutants and wild type. Our data provide evidence of increased CD4+ and CD8+ T cell recycling in the HIV-infected patients.

Adult↗

PubMed1997

Homozygosity mapping at Alström syndrome to chromosome 2p.

Alström syndrome is a rare autosomal recessive disorder characterized by pigmentary retinal degeneration, sensorineural hearing loss, childhood obesity, non-insulin-dependent diabetes mellitus, hyperlipidemia and chronic nephropathy. Features occasionally observed include acanthosis nigricans, hypogonadism, hypothyroidism, alopecia, short stature and cardiomyopathy. We report here the results of a linkage study in a large French Acadian kindred, as a first step in identifying the molecular basis of Alström syndrome. Evidence of a founder effect made if feasible to use a homozygosity mapping strategy to identify the chromosomal location of the Alström gene. In a genome-wide screen, haplotype sharing for a region on chromosome 2 was observed in all affected individuals. Two point linkage analysis resulted in a maximum lod score of 3.84 (theta = 0.00) for marker D2S292. By testing additional markers, the disease gene was localized to a 14.9 cM region on chromosome 2p.

Abnormalities, Multiple↗

PubMed1996

Cross-linking of the CD40 ligand on human CD4+ T lymphocytes generates a costimulatory signal that up-regulates IL-4 synthesis.

Although there is good evidence that the induction of IL-4 synthesis in CD4+ T lymphocytes is favored by Ag presentation by B cells and not macrophages, the precise molecular signals provided by B cells to T cells that enhance IL-4 synthesis are not clear. To examine this issue, we established an APC-independent system to activate highly purified T cells and induce cytokine synthesis, using immobilized mAbs against several T cell surface molecules, including CD3, CD28, and the CD40 ligand (CD40L). The counter-receptors for all three of these molecules are expressed on B cells, and include CD40, which is expressed primarily on B cells, but also on dendritic cells and thymic epithelium. We found that IL-4 synthesis was greatly enhanced by triggering of CD40L on the T cell surface in conjunction with ligation of CD3/TCR and CD28, whereas ligation of CD3/TCR and CD28 in the absence of CD40L triggering resulted in little or no IL-4 synthesis. CD40L costimulation greatly enhanced IL-4 synthesis both in T cells from normal nonallergic adult subjects as well as in naive T cells from cord blood. Furthermore, we demonstrated that IL-4 synthesis was optimally enhanced when the strength of the CD3/TCR signal was limiting, while IL-4 synthesis was inhibited when CD3/TCR stimulation was maximal. These studies confirm that IL-4 synthesis can be induced in normal T lymphocytes in the absence of exogenous IL-4, and demonstrate that CD40L costimulation is of fundamental importance in regulation of IL-4 production. In addition, these findings provide a mechanism by which B cells preferentially enhance IL-4 synthesis in T cells at low Ag concentrations.

Adult↗

PubMed1996

Pharmacokinetics and pharmacodynamics of famotidine in children.

The pharmacokinetics and pharmacodynamics of intravenous famotidine were studied in 12 children (1.1-12.9 years of age; mean weight +/- standard deviation = 27.6 +/- 21.2 kg) who were given the drug for prophylactic management of stress ulceration. After a 0.5-mg/kg infusion of famotidine, timed blood (n = 10) and urine (n = 6) samples and repeated evaluations of intragastric pH (n = 13) were obtained from each subject. Pharmacokinetic parameters were determined from curve fitting of serum concentration data. The mean (+/- SD) maximum serum concentration (Cmax) was 527.6 +/- 281.2 ng/mL, the elimination half-life (t1/2) was 3.2 +/- 3.0 hours, and the apparent steady-state volume of distribution (Vdss) was 2.4 +/- 1.7 L/kg. Plasma clearance (Cl) and renal clearance (ClR) were 0.70 +/- 0.34 L/hr/kg and 0.43 +/- 0.24 L/hr/kg, respectively. Over 24 hours, 73.0 +/- 27.3% of the dose was excreted unchanged in the urine (Fel). Pharmacodynamic analysis of gastric pH data using the sigmoid Emax model predicted that 50% of the maximal effect of famotidine (EC50) occurs at a serum concentration of 26.0 +/- 13.2 ng/mL. Children who did not have an initial intragastric pH < or = 4 did not have a significant response in pH after receiving famotidine. Although Vdss and Cl were higher in these children than those seen in adults, statistically significant relationships between these parameters and age were not observed in the study population. The pharmacodynamics and pharmacokinetics of famotidine in children older than one year of age appear to be similar to those noted in adults.

Child↗

PubMed1996

Body dissatisfaction and drive for thinness in high performance field hockey athletes.

The prevalence of eating disordered tendencies and its relationship to body composition was examined in elite female field hockey players. Eating Disorder Inventory (EDI) and body composition (skinfold) data were collected from 111 (92.5%) athletes from 12 teams at the 1994 Indoor Canadian National Tournament. Athletes at risk for developing frank eating disorders were identified using cutoff scores of clinically diagnosed patients with eating disorders. 19/111 (17.1%) demonstrated increased body dissatisfaction (BD), and 4/111 (3.6%) an elevated drive for thinness, suggesting that concern for body shape and size is a greater issue in field hockey than preoccupation with weight. Compared to athletes not at risk, those with elevated BD scores were significantly heavier, fatter, and had higher BMIs. Although it appears that these athletes may have reason to be dissatisfied, they may be at increased risk for initiating and sustaining weight controlling behaviours associated with eating disorders. Special care must be taken in any intervention strategy.

Adolescent↗

PubMed1995

IL-12 inhibits the production of IL-4 and IL-10 in allergen-specific human CD4+ T lymphocytes.

IL-12 influences cytokine synthesis in unprimed CD4+ T cells by enhancing IFN-gamma synthesis and enhancing the development of Th1 cells, but its effects upon Ag-primed T cells, which are thought to have relatively fixed cytokine profiles, is less clear. We investigated the capacity of IL-12 to modify cytokine synthesis in allergen-specific human CD4+ T lymphocytes from allergic donors after in vitro stimulation. CD4+ T cells were obtained from the peripheral blood of subjects with allergic rhinitis, depleted of activated T cells, and cultured with APCs and allergen. IL-12 dramatically inhibited the development of IL-4 and IL-10 synthesis, while it enhanced T cell secretion of IFN-gamma and IL-2, and enhanced Ag-specific T cell proliferation. The inhibitory effect of IL-12 on IL-4 synthesis was not dependent on the presence of IFN-gamma, was greatest when IL-12 was added at the initiation of culture, and was minimal when added late, indicating that resting memory CD4+ T cells were more sensitive than activated CD4+ T cells to the effects of IL-12. The effect of IL-12 on IL-4 and IL-10 synthesis was not dependent on the APC type, because IL-12 decreased IL-4 synthesis when either B cells or monocytes served as APCs. These results indicate that IL-12 may be therapeutically beneficial in the treatment of allergic diseases in which allergen-specific T cells characteristically produce enhanced quantities of IL-4 and IL-10.

Antigen-Presenting Cells↗

PubMed1995

Diarrhea associated with enteral benzodiazepine solutions.

Diarrhea occurred in an infant given large enteral doses of benzodiazepine solutions that contained the carriers propylene glycol and polyethylene glycol. This adverse drug effect may be avoided by prescribing the tablet formulations appropriately prepared for enteral administration.

Anti-Anxiety Agents↗

PubMed1995

Human alveolar macrophages present antigen ineffectively due to defective expression of B7 costimulatory cell surface molecules.

Alveolar macrophages, resident phagocytic cells in the lung that derive from peripheral blood monocytes, are paradoxically ineffective in presenting antigen to T cells. We found that antigen presentation by alveolar macrophages could be restored by the addition of anti-CD28 mAb to cultures of T cells and macrophages, indicating that costimulation by alveolar macrophages via the CD28 pathway was defective. In addition, we found that alveolar macrophages activated with IFN-gamma failed to express B7-1 or B7-2 antigens, which normally ligate CD28 on T cells and provide a costimulatory signal required for the activation of T cells. These observations are the first to demonstrate the inability of a "professional" antigen-presenting cell type to effectively express the costimulatory molecules B7-1 and B7-2. Inasmuch as immune reactions within the lung are inevitably associated with inflammatory injury to pulmonary tissue, these observations suggest that reduced expression of B7-1 and B7-2 by alveolar macrophages may be advantageous, as a critical mechanism involved in the induction of peripheral tolerance to the abundance of antigens to which mucosal tissues are continuously exposed.

Adult↗

PubMed1994

Stable carbon isotope discrimination, photosynthetic gas exchange, and growth differences among western larch families.

Photosynthetic gas exchange, stable carbon isotope discrimination (Delta), height and diameter were compared among five open-pollinated families of 12-year-old western larch trees growing in a common garden in Moscow, Idaho, USA. Statistically significant variation was detected among the families in the two growth traits, Delta and stomatal conductance to water vapor (g) (P </= 0.013), but differences among families in photosynthetic rate (A) and water-use efficiency (W) were not significant (P >/= 0.203). Water-use efficiency was strongly correlated with Delta (r = -0.95, P < 0.01). Neither growth trait was correlated with A (r </= 0.05, P > 0.93) and height was not significantly correlated with Delta (r = -0.75, P = 0.15). Tree diameter and Delta were significantly correlated (r = -0.92, P = 0.03). These results were strongly influenced by a single family. Both the variation in Delta and correlation trends between Delta and the growth traits height and diameter suggest the possibility of selecting for high water-use efficiency with the potential for simultaneous gains in height and diameter growth.

Journal Article↗

PubMed1993

Allergen immunotherapy decreases interleukin 4 production in CD4+ T cells from allergic individuals.

Allergen specific CD4+ T cell clones generated from allergic individuals have been shown to produce increased levels of the cytokine interleukin 4 (IL-4), compared to allergen specific clones generated from nonallergic individuals. This difference between CD4+ T cells from allergic and nonallergic individuals with regard to cytokine production in response to allergen is thought to be responsible for the development of allergic disease with increased IgE synthesis in atopic individuals. We examined the production of IL-4 in subjects with allergic rhinitis and in allergic individuals treated with allergen immunotherapy, a treatment which involves the subcutaneous administration of increasing doses of allergen and which is highly effective and beneficial for individuals with severe allergic rhinitis. We demonstrated that the quantity of IL-4 produced by allergen specific memory CD4+ T cells from allergic individuals could be considerably reduced by in vivo treatment with allergen (allergen immunotherapy). Immunotherapy reduced IL-4 production by allergen specific CD4+ T cells to levels observed with T cells from nonallergic subjects, or to levels induced with nonallergic antigens such as tetanus toxoid. In most cases the levels of IL-4 produced were inversely related to the length of time on immunotherapy. These observations indicate that immunotherapy accomplishes its clinical effects by reducing IL-4 synthesis in allergen specific CD4+ T cells. In addition, these observations indicate that the cytokine profiles of memory CD4+ T cells can indeed be altered by in vivo therapies. Thus, the cytokine profiles of memory CD4+ T cells are mutable, and are not fixed as had been suggested by studies of murine CD4+ memory T cells. Finally, treatment of allergic diseases with allergen immunotherapy may be a model for other diseases which may require therapies that alter inappropriate cytokine profiles of memory CD4+ T cells.

Adult↗

PubMed1993

Multiple mechanisms of tumorigenesis in E mu-myc transgenic mice.

Transgenic mice bearing a c-myc oncogene under control of the immunoglobulin heavy chain enhancer (E mu-myc mice) reproducibly develop and die from tumors of the B lymphocyte lineage (J.M. Adams, A.W. Harris, C.A. Pinkert, L.M. Corcoran, W.S. Alexander, S. Cory, R.D. Palmiter, and R.L. Brinster, Nature (Lond.), 318: 533-538, 1985; W.Y. Langdon, A. W. Harris, S. Cory, and J.M. Adams, Cell 47: 11-18, 1986; A.W. Harris, C.A. Pinkert, M. Crawford, W.Y. Langdon, R.L. Brinster, and J.M. Adams, J. Exp. Med., 167: 353-371, 1988; reviewed in S. Cory and J.M. Adams, Annu. Rev. Immunol., 6: 25-48, 1988). Analysis of lymphocytes obtained by serial sampling of peripheral blood from individual hemizygous (E mu-myc/0) and homozygous (E mu-myc/E mu-myc) transgenic mice indicates that proliferation in the original host and transplantability into histocompatible recipients are distinct properties that can be acquired independently and in either order. These two types of transgenic mice differ in that homozygous mice have about one-fourth the life span of hemizygous mice and develop polyclonal, non-transplantable tumors in comparison to the oligoclonal, highly transplantable malignancies seen in hemizygous animals. In conclusion, the overall concept of malignancy is best viewed as an aggregate of the separable parameters of cellular proliferation, clonality, tissue invasiveness, metastasis, and (experimental) transplantability. The E mu-myc transgenic mouse represents an attractive model in which to investigate the multistep nature and alternative pathways of tumorigenesis.

Animals↗

PubMed1993

In vitro synthesis of IL-4 by human CD4+ T cells requires repeated antigenic stimulation.

Although Th2 helper cell clones produce IL-4 and IL-5, CD4+ T cells taken fresh from lymphoid organs of mice produce IL-2 and some IFN-gamma, but not IL-4 or IL-5. The exact parameters that enhance the synthesis of IL-4, IL-5, and particularly IL-10 from resting antigen-specific CD4+ T cells is not yet clear. We therefore examined the kinetics of, and the parameters that affect, the development of IL-4, IL-5, and IL-10 production in bulk populations of antigen-specific human CD4+ T cells. We demonstrated that in vitro stimulation of human peripheral blood lymphocytes with antigen (tetanus toxoid or a viral antigen, Varicella zoster) for several days resulted in the production of IL-2 and IFN-gamma, but little or no IL-4 or IL-5. This cytokine profile was observed even when CD4+ T cells from allergic donors were stimulated once in vitro with allergen (rye grass pollen, Lolium perenne I, or dust mite allergen, Dermatophagoides farinae). The observed cytokine profile reflected that of the vast majority of antigen-specific T cells, since we studied the response of bulk populations of CD4+ T cells rather than that of a "selected" number of antigen-specific T cell clones. Furthermore, we observed that human CD4+ T cells from either allergic or nonallergic individuals failed to produce significant quantities of IL-4, IL-5, or IL-10 even after several rounds of stimulation with soluble protein (nonallergen) antigens such as tetanus toxoid or Var. z. However, large quantities of these cytokines were produced when stimulation of the T cells occurred in the presence of rIL-4, but only after two stimulations in vitro with antigen over a period of greater than 7 days. In addition, substantial quantities of IL-4, IL-5, and IL-10 were produced by CD4+ T cells from allergic subjects in the absence of exogenous IL-4, but only after two stimulations in vitro with allergens such as rye grass pollen or dust mite allergen. These results indicate that the development of IL-4 and IL-5 synthesis occurs in peripheral blood CD4+ T cells in a stepwise fashion, first with the production of IL-2 and IFN-gamma, and later with the production of IL-4 and IL-5.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens↗