Identification of monocyte chemotactic factors in supernatants of ovalbumin-stimulated lymphocytes from patients with atopic dermatitis who are sensitive to hen's egg

Monocyte chemotactic activities in supernatants of ovalbumin (OA)-stimulated peripheral blood mononuclear cell (PBMC) cultures were studied in patients with atopic dermatitis (AD) who were sensitive to hen's egg. The monocyte chemotactic activities in hen's egg-sensitive AD patients were significantly higher than those of non-atopic healthy controls and patients with immediate allergic symptoms. However, the monocyte chemotactic activities were not detected in bovine serum albumin-stimulated PBMC culture supernatants in patients with AD who were sensitive to hen's egg, but not to cow's milk. Furthermore, there was significant correlation between the monocyte chemotactic activities and proliferative responses of PBMCs to OA in hen's egg-sensitive AD patients, whereas there was no significant correlation between the monocyte chemotactic activities and radioallergosorbent test values. These results suggest that PBMCs stimulated with food antigens produce monocyte chemotactic factors which relate to the pathogenesis of AD in food-sensitive AD patients and that the pathogenesis of AD may be related to cell-mediated immune responses.

Structure of vulnibactin, a new polyamine-containing siderophore from Vibrio vulnificus

A new siderophore named vulnibactin has been isolated from low iron cultures of Vibrio vulnificus, a human pathogen. The structure was established as N-[3-(2,3-dihydroxybenzamido)propyl]-1,3-bis[2-(2-hydroxy-phenyl)- trans-5 - methyl-2-oxazoline-4-carboxamido]propane by a combination of acid hydrolysis, nuclear magnetic resonance spectroscopy and positive fast atom bombardment mass spectrometry. Vulnibactin is characterized as containing one residue of 2,3-dihydroxybenzoic acid as well as two residues of salicylic acid, both of which are involved in the formation of oxazoline rings with L-threonine bound to a norspermidine backbone. In addition, two other compounds with siderophore activity were purified and their structures were also determined. These two compounds provided further support for the structure of vulnibactin.

Relationship between cytosolic Ca2+ level and contractile tension in canine basilar artery of chronic vasospasm

In order to study the role of the Ca2+/calmodulin/myosin light chain kinase system in the development of chronic vasospasm caused by subarachnoid hemorrhage, the cytosolic Ca2+ level ([Ca2+]i), measured with fura-2, a fluorescent Ca2+ indicator, and contractile tension were measured simultaneously, and their quantitative correlation was examined in basilar arterial tissue obtained from the canine "two-hemorrhage" model. Sixteen adult mongrel dogs were divided into two groups, control (n = 8) and vasospasm (n = 8), and were killed 7 days after the first experimental subarachnoid hemorrhage. In basilar arterial tissue loaded with fura-2, 1) [Ca2+]i in the resting condition was not significantly different between the two groups; 2) the increment in [Ca2+]i induced by 40 mmol/L K+ stimulation was significantly smaller in vasospastic tissue (P < 0.01); and 3) 40 mmol/L K(+)-induced tension development per cross-sectional area for a fixed increment in [Ca2+]i was significantly greater in vasospastic tissue (P < 0.01). In tissue not loaded with fura-2, active myogenic tone, which was tentatively represented by the ratio of tonus relaxed with 10(-4) mol/L papaverine to initial resting tone, was significantly greater in vasospastic tissue (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Purification and properties of Saccharomyces cerevisiae cystathionine beta-synthase

Cystathionine beta-synthase (beta-CTSase), which catalyses cystathionine synthesis from serine and homocysteine, was purified to homogeneity from Saccharomyces cerevisiae. The molecular mass of the enzyme was estimated to be 235 kDa by gel filtration and 55 kDa by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, indicating that it is a homotetramer. The N-terminal amino acid sequence of the enzyme perfectly coincided with that deduced from the nucleotide sequence of CYS4, except for the absence of initiation The purified beta-CTSase catalysed cysteine synthesis from serine (or O-acetylserine) and H2S. From this finding, we discuss the multifunctional nature and evolutionary divergence of S-metabolizing enzymes.

Proliferative responses towards native, heat-denatured and pepsin-treated ovalbumin by peripheral blood mononuclear cells from patients with hen's egg-sensitive atopic dermatitis

In order to clarify the mechanism of food-antigen recognition, the proliferative responses of peripheral blood mononuclear cells (PBMCs) to native, heat-denatured or pepsin-treated ovalbumin (OA) were investigated in 16 hen's egg-sensitive patients with atopic dermatitis (AD). Seven of them had hypersensitivity to boiled hen's egg and others had not. The responses of PBMCs to heat-denatured OA were lower than those to native OA in the patients without hypersensitivity to boiled hen's egg. However, there were no differences of the responses of PBMCs between heat-denatured OA and native OA in the patients with hypersensitivity to boiled hen's egg. Moreover, the reduction of the responses of PBMCs to pepsin-treated OA was recognized in six out of seven patients. The primary structure of OA did not change by heating or pepsin treatment according to sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). These results suggested that the secondary structure of OA changed in connection with the reduction of the responses of PBMCs to denatured OA. In addition, we demonstrated the suppressive effect of anti-HLA-DR and anti-HLA-DQ monoclonal antibodies on the proliferative response of PBMCs to OA. The results suggested that the proliferative responses of PBMCs to OA were restricted by HLA-DR or HLA-DQ in hen's egg-sensitive patients with AD.

Suppression of proliferative responses of lymphocytes to food antigens by an anti-allergic drug, ketotifen fumarate, in patients with food-sensitive atopic dermatitis

Experimental studies have shown that ketotifen fumarate inhibits reaginic antibody-mediated hypersensitivity reactions. In this study, the proliferative responses of peripheral blood mononuclear cells (PBMCs) to ovalbumin (OA) in children with atopic dermatitis (AD), who are sensitive to hen's egg, were significantly higher than those of healthy children. The proliferative responses of PBMCs to OA were dose-dependently inhibited by ketotifen in patients with hen's egg-sensitive AD. Moreover, the inhibition resulted from the effects of ketotifen on T cells. In contrast, the proliferative responses of PBMCs to phytohemagglutinin and tetanus toxoid were not inhibited by ketotifen. These results suggest that ketotifen inhibits food antigen-specific proliferative responses of PBMCs in patients with food-sensitive AD.

Simple purification method for a Vibrio vulnificus hemolysin by a hydrophobic column chromatography in the presence of a detergent

A Vibrio vulnificus hemolysin (VVH) was purified by two steps of hydrophobic column chromatography on Phenyl-Sepharose HP. The first chromatography was carried out at pH 6.0. In this pH condition, VVH efficiently bound to the column, but the hemolysin fraction eluted was accompanied with colored substance(s). To eliminate this colored substance, the second chromatography was carried out at pH 9.8 in the presence of 1% 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS), a zwitterionic detergent. Homogeneity of the hemolysin thus obtained was shown by polyacrylamide gel electrophoresis. The specific activity increased 33,600 times and the yield was 35%. The method is simple and useful to supply enough VVH for study of the role of the hemolysin in the infection by V. vulnificus or on the mechanism of action of the hemolysin.

Immunoglobulin-secreting cells in healthy peripheral blood mononuclear cells

Immunoglobulin-secreting cells were measured in healthy uncultured peripheral blood mononuclear cells (PBMCs) in vitro. The percentage of IgM-, IgG- and IgA-secreting cells in adult PBMCs was 0.053, 0.099 and 0.065%, respectively. The percentage of IgM-, IgG- and IgA-secreting cells was 0.73, 5.2 and 3.8% of surface IgM-, IgG- and IgA-bearing cells, respectively. The numbers of IgM-, IgG- and IgA-secreting cells increased with age in childhood. However, the numbers of all three classes were slightly decreased in adults compared with children aged 9-15 years. These results may explain the difference in immunity in vivo.

[Evaluation of the postoperative regrowth of the acoustic neurinomas]

Although recent advances in microsurgical removal of acoustic neurinomas has made it possible to preserve, morphologically, the cochlear nerve as well as the facial nerve, functional impairment of the facial nerve is often encountered following total removal of the tumor. In order to avoid such functional morbidity, a surgical procedure can be proposed in which the tumoral capsule attached to a functional structure such as the facial nerve is intentionally left. Along with this surgical procedure and postoperative course observation, postoperative regrowth of the tumor should be precisely evaluated. A few recent reports about this problem have been published since CT scan and MRI have become available. The authors reviewed 66 cases in which postoperative evaluation by high resolution CT scan of the acoustic neurinomas has been carried out in their department more than one year after surgery. Multiple factors such as age at onset, sex, preoperative period, tumor size, vascularity, extent of the tumor removal, residual site, and pathological findings on HE stain were studied in relation to the tumor regrowth. Four cases showed regrowth of the tumor, and one of these tumors was reoperated on. The percentage of regrowth was 7.5% among the tumors which were not totally removed. No significant risk factors for tumor regrowth were noticed in these cases, but tumor regrowth tended to be found in younger patients. The residual tumors which showed regrowth were always located in the internal auditory meatus. In this study, it is apparent that, percentagewise, tumor regrowth is not so prevalent.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoglobulin-secreting cells in primary immunodeficiency diseases

To assess immunoglobulin production in vivo, the numbers of immunoglobulin-secreting cells were measured in uncultured peripheral blood mononuclear cells (PBMCs) of patients with primary immunoglobulin deficiency. The numbers of immunoglobulin-secreting cells were found to be variable, and they were well correlated with the serum concentrations of all three major immunoglobulin classes. Our results suggest that measurement of immunoglobulin-secreting cells in PBMCs is useful in the assessment of the ability to produce immunoglobulin in vivo.

Suppressive effects of elimination diets on T cell responses to ovalbumin in hen's egg-sensitive atopic dermatitis patients

We investigated the effect of elimination diets on T cell responses to ovalbumin (OA) in hen's egg-sensitive atopic dermatitis (AD) patients. The proliferative responses of both peripheral blood mononuclear cells (PBMCs) and T cells with monocytes to OA decreased after elimination diets, but those to Candida albicans or phytohemagglutinin (PHA) did not decrease after elimination diets. The proliferative responses of CD4+ T cells with monocytes to OA decreased after elimination diets. In these patients, clinical symptoms of AD improved. These results indicate that T cells, especially CD4+ T cells, respond to food antigens in food-specific lymphocyte responses, and that elimination diets may be able to initiate reduction of the responsiveness of food-sensitive T cells, especially CD4+ T cells. Moreover, the surface marker phenotypes of the T cells responding to OA were analysed. Our results showed that CD4+CD45RA+ T cells tended to increase. The increase in circulating CD4+CD45RA+ T cells might function as systemic suppression against immune responses in the skin.

Relationship between chromosomal alpha-specific suppressors of sir4-11 and polymorphism of the HMRa-bearing fragment

In the course of studying sir4-11 which is responsible for the non-mating phenotype of asd-homothallism of Saccharomyces cerevisiae, we detected chromosomal alpha-specific suppressors of it. By examining the mating-type cassette constitution of two strains and the spore-clones derived from a diploid culture formed by a mass mating between these strains, we obtained the following results; (1) the HMRa-bearing HindIII-Bg/II restriction fragment was dimorphic, as judged by size, within each tetrad, (2) while one form was common to all tetrads, the other varied among tetrads, (3) spore-clones with the alpha-specific suppressor of sir4-11 had the variant forms while those without had the common form, and (4) while the two parents had the common form, each independent diploid clone had the common form plus a variant form. From these results, we conclude that the mating of cells in certain combinations induces a change of DNA structure at or near HMRa in a mating-pair specific manner and that the change makes HMRa non-derepressible or non-functional when derepressed.

Evaluation of lymphocyte proliferative responses to food antigens with regard to age and food-specific IgE antibodies in food-sensitive atopic dermatitis

Peripheral blood mononuclear cells (PBMCs) from patients with atopic dermatitis (AD), selected for sensitivity to hen's egg or cow's milk, showed significant proliferation in response to food antigens, ovalbumin or bovine serum albumin compared with PBMCs from nonatopic control subjects. The proliferative responses of PBMCs to food antigens were evaluated with regard to age and specific IgE antibodies to food antigens in food-sensitive patients with AD. There were no differences in proliferation between each age group, and the proliferation in patients with AD was significantly higher than in age-matched control subjects. There was no relationship between proliferative responses of PBMCs and specific IgE antibodies to food antigens in patients with AD. These results suggest that the responsiveness of lymphocytes to food antigens is independent of age and food-specific IgE antibodies in food-sensitive patients with AD.

Studies on hemolytic action of a hemolysin produced by Vibrio mimicus

Some properties and mechanism of action of a hemolysin (VMH) produced by an enteropathogenic Vibrio mimicus strain was examined. VMH was heat-labile and inhibited by addition of divalent cations, including Ca2+, Mg2+ and Mn2+. The hemolysis by VMH was inhibited by incubating with gangliosides, suggesting that the ganglioside was the binding site on the erythrocyte membrane for VMH. Existence of a galactose moiety on reducing end of the ganglioside molecule and a sialic acid on the galactose moiety was suggested to be important for the binding of VMH molecule. Colloid osmotic manner of the hemolysis by VMH was demonstrated.

[A case of arteriovenous malformation with cyst formation]

A case of arteriovenous malformation (AVM) with cyst formation is reported. A 14-year-old girl was admitted to our hospital, complaining of headache. On admission, CT scan showed a cystic mass with mural nodule in the right parietal lobe. Contrast enhanced CT scan demonstrated homogeneous enhancement of the nodule. MRI demonstrated the nodule as an area of signal void. Right carotid angiogram showed a typical nidus with feeding artery and draining vein. The nidus was totally removed by the trans-cystic approach. Histological diagnosis was typical AVM with hemosiderin deposits. AVM with cyst formation is very rare, with only six cases having been reported. The mechanism of cyst formation is controversial. Past reports have hypothesized the participation of a massive hemorrhage, or exudative process. Our case showed hemosiderin deposits, but no symptom indicative of hemorrhage. In this case, the etiology of cyst formation was considered to be exudation and thrombosis of the nidus.

Structures of two polyamine-containing catecholate siderophores from Vibrio fluvialis

From low-iron cultures of Vibrio fluvialis AQ 0012, two new compounds with siderophore activity were purified by XAD-7 adsorption followed by preparative TLC. Norspermidine and 2,3-dihydroxybenzoic acid were identified as constituents common to both compounds by GC-MS analyses of their acid hydrolytic products. In addition, L-threonine was identified in the hydrolysate of one compound, named fluvibactin. Based on high magnetic NMR analyses, the structure of fluvibactin was established as N4-[2-(2,3-dihydroxy-phenyl)-trans-5-methyl-2-oxazoline-4-yl]carboxy-N1, N7- bis-(2,3-dihydroxybenzoyl)-norspermidine, and that of the other compound as N1,N7-bis-(2,3-dihydroxybenzoyl)-norspermidine. The structures were supported by fast atom bombardment mass spectrometry. Both of the purified compounds restored growth inhibition of the producer strain and V. cholerae Non-O1 induced by ethylenediamine di-(o-hydroxyphenylacetic acid), a potent synthetic chelating agent of ferric iron.

Cystathionine gamma-lyase of Saccharomyces cerevisiae: structural gene and cystathionine gamma-synthase activity

Purification of Saccharomyces cerevisiae cystathionine gamma-lyase (gamma-CTLase) was hampered by the presence of a protein migrating very close to it in various types of column chromatography. The enzyme and the contaminant were nevertheless separated by polyacrylamide gel electrophoresis. N-terminal amino acid sequence analysis indicated that they are coded for by CYS3 (CYI1) and MET17 (MET25), respectively, leading to the conclusion that CYS3 is the structural gene for gamma-CTLase and that the contaminant is O-acetylserine/O-acetylhomoserine sulfhydrylase (OAS/OAH SHLase). Based on these findings, we purified gamma-CTLase by the following strategy: (1) extraction of OAS/OAH SHLase from a CYS3-disrupted strain; (2) preparation of antiserum against it; (3) identification of a strain devoid of the OAS/OAH SHLase protein using this antiserum; and (4) extraction of gamma-CTLase from this strain. Purified gamma-CTLase had cystathionine gamma-synthase (gamma-CTSase) activity if O-succinylhomoserine, but not O-acetylhomoserine, was used as substrate. From this notion we discuss the evolutional relationship between S. cerevisiae gamma-CTLase and Escherichia coli gamma-CTSase.

Chemical modification of Vibrio vulnificus metalloprotease with activated polyethylene glycol

Vibrio vulnificus, an opportunistic human pathogen causing septicemia, produces a metalloprotease which is suspected to be a virulence determinant, but which is labile in vivo due to inactivation by alpha-macroglobulin. To obtain a derivative which is stable in vivo, the metalloprotease was modified with activated monomethoxy polyethylene glycol. The modified protease retained full activity to a peptide substrate and 10-20% activity to protein substrates, and was resistant to entrapment by alpha-macroglobulin because of the increased molecular size (approx. 90 kDa). These findings suggest that the modified protease is stable in vivo and may be used to investigate the pathological actions of the protease in the bloodstream.

The role of T lymphocytes in patients with food-sensitive atopic dermatitis

The role of T lymphocytes was assessed in patients with food-sensitive atopic dermatitis (AD). T lymphocytes plus monocytes responded well to ovalbumin or bovine serum albumin (BSA) in children with AD who were sensitive to hen's egg or cow's milk compared with healthy children and children with immediate allergic symptoms who are sensitive to hen's egg or cow's milk. The responding cells were shown to be predominantly CD4+ T lymphocytes. Interleukin-2 activity and interferon-gamma concentrations in culture supernatants of ovalbumin-stimulated peripheral blood mononuclear cells (PBMCs) from patients with AD who were sensitive to hen's egg were significantly higher than those of healthy children and patients sensitive to hen's egg with immediate symptoms. Expression of Fc epsilon R II on B lymphocytes in cultures of ovalbumin-stimulated PBMCs from patients with AD was significantly higher than that of healthy children, but it tended to be lower than that of patients with immediate symptoms. These results suggest that, in patients with AD who are food sensitive, CD4+ T lymphocytes stimulated by food antigens secrete lymphokines such as interleukin-2 and interferon-gamma that are secreted from TH1 clones in mice, and express Fc epsilon R II on B lymphocyte that is induced by interleukin-4 secreted from TH2 clones in mice. Taken together, cell-mediated immunity may also occur in addition to IgE-mediated hypersensitivity in patients with food-sensitive AD.

Effect of elimination diets on food-specific IgE antibodies and lymphocyte proliferative responses to food antigens in atopic dermatitis patients exhibiting sensitivity to food allergens

Peripheral blood mononuclear cells (PBMCs) from patients with atopic dermatitis (AD) selected as being sensitive to hen's egg or cow's milk responded to food antigens, ovalbumin, or bovine serum albumin, with significantly enhanced DNA synthesis compared with the DNA synthesis in PBMCs from nonatopic control subjects and food-sensitive patients with immediate symptoms. Patients were treated with elimination diets. Symptoms of AD had been in remission during elimination diets. The levels of specific IgE antibodies to hen's egg or cow's milk decreased during elimination diets in patients with positive radioallergosorbent test (RAST). In patients with negative RAST, specific IgE antibodies remained negative during elimination diets. The proliferative responses of PBMCs to food antigens also decreased during elimination diets in patients with proliferative responses before elimination diets. Taken together, specific IgE antibodies to food antigens are useful indexes of the effect of elimination diets in food-sensitive patients with AD and positive RAST, and proliferative responses of PBMCs to food antigens are useful indexes of the effect of elimination diets in food-sensitive patients with AD and proliferative responses of PBMCs.

Improvement of food-sensitive atopic dermatitis accompanied by reduced lymphocyte responses to food antigen following natural measles virus infection

Five patients with atopic dermatitis (AD) who were sensitive to hen's egg were observed before and after natural measles virus infection. Within 4 weeks of natural measles virus infection, the eczematous lesions clearly improved in four of the five patients in whom neither offending foods were eliminated, nor anti-allergic drugs, systemic steroids and steroid ointment administered. This was accompanied by reduced proliferative responses of peripheral blood mononuclear cells (PBMCs) to ovalbumin (OA). Another patient showed a transient improvement of AD symptoms, from severe to mild, and thereafter returned to severe accompanied by increased proliferative responses of PBMCs to OA. Radioallergosorbent test (RAST) scores for hen's egg in all five patients did not change in each level in each patient, except the transiently decreased RAST scores for hen's egg in one patient, after the infection. Thus, in patients with AD who are sensitive to food, the improvement of AD symptoms that appeared within 4 weeks of natural measles virus infection was related to reduced proliferative responses of PBMCs to the food antigen following the infection.

Magnetic resonance imaging of ganglion cell tumours

The MRI and CT studies of four patients with ganglion cell tumours, one with a cerebellar gangliocytoma (Lhermitte-Duclos disease), and three with gangliogliomas are reported. MRI in Lhermitte-Duclos disease clearly demonstrated a mass of low signal intensity in the left cerebellum on T1-weighted spin-echo (SE) images and an area of high signal intensity with a blurred margin on T2-weighted SE images. These MRI studies were useful for delineating the lesion, which was verified at surgery. In the ganglioglioma, MRI demonstrated two isointense solid masses on T1-weighted SE images, which enhanced clearly with Gd-DTPA. The enhancement study was advantageous in planning surgery.

Bioavailabilities of calcium, phosphorus and magnesium from whey mineral complex in growing male rats

The bioavailabilities of Ca, P and Mg from whey mineral complex (WMC) were studied from the viewpoint of the mineral balance and bone properties in growing male rats and compared with bovine bone ash (BBA) and CaCO3. Ca source showed no significant effect on feed intake, body weight gain or feed efficiency (p < 0.05). When the dietary Ca level was 0.3%, the dry weight of the femur in rats fed WMC was significantly higher than that in rats fed BBA. The femur P content of rats fed 0.3% Ca as WMC was significantly higher than that of rats fed BBA or CaCo3. The breaking energy of the femur from rats fed WMC was significantly higher than that from rats fed BBA at a Ca level of 0.2% or 0.3%. There was the same tendency in bone densities as was observed in breaking properties. There was no significant difference in quantitative values for Ca balance among three groups of rats, whereas those rats fed WMC had a significantly higher P retention than other groups. Ca bioavailability from WMC and the effect on the utilization of P and Mg were discussed.

Lymphocyte responses to food antigens in food sensitive patients with allergic tension-fatigue syndrome

Scores of radioallergosorbent test (RAST) for cow's milk or buckwheat flour and proliferative responses of peripheral blood mononuclear cells (PBMCs) to bovine serum albumin and beta-lactoglobulin or buckwheat flour were measured in cow's milk or buckwheat flour sensitive patients with allergic tension-fatigue syndrome. In all 3 cow's milk sensitive patients with allergic tension-fatigue syndrome, RAST scores for cow's milk were negative or slightly positive, but PBMCs well responded to bovine serum albumin and beta-lactoglobulin, but not to ovalbumin. In a buckwheat flour sensitive patient with allergic tension-fatigue syndrome, RAST scores for buckwheat flour were negative, but PBMCs well responded to buckwheat flour, but not to ovalbumin, bovine serum albumin and beta-lactoglobulin. Conversely, in cow's milk or buckwheat flour sensitive patients with immediate allergic symptoms, RAST scores for offending foods were positive although PBMCs did not respond to offending food antigens. These results suggest that proliferative responses of PBMCs to food antigens are very useful for detection of offending foods in allergic tension-fatigue syndrome.

Proliferative responses of CD4+ T-cell population to ovalbumin in patients with atopic dermatitis who are sensitive to hen eggs

Proliferative responses of peripheral blood mononuclear cells and T cells with monocytes to ovalbumin were significantly higher than those of B cells with monocytes to ovalbumin in patients with atopic dermatitis (AD) who were sensitive to hen eggs. The CD4+ T-cell/CD8+ T-cell ratios (the values obtained by dividing the maximum stimulation index of CD4+ T cells with monocytes to ovalbumin by the maximum stimulation index of CD8+ T cells with monocytes to ovalbumin) were significantly higher in AD patients sensitive to hen eggs than in non-atopic healthy controls. The proliferative responses of CD4+ T cells with monocytes to ovalbumin were more intensive than those of CD8+ T cells with monocytes in patients with AD sensitive to hen eggs compared with non-atopic healthy controls. These results suggest that the cells responding to ovalbumin are predominantly CD4+ T cells. However, there was no relationship between the stimulation index of proliferative responses of peripheral blood mononuclear cells to ovalbumin and RAST scores for hen eggs. Thus it is possible that the majority of the CD4+ T cells which respond to ovalbumin are not CD4+ helper T cells for IgE production.