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PubMed1990

The mechanism of mediator release from human basophils induced by platelet-activating factor.

Platelet-activating factor (PAF) is a lipid mediator able to induce a variety of inflammatory processes in human peripheral blood cells. We have investigated the effect of PAF on the release of chemical mediators from human basophils of allergic and normal donors. PAF (10 nM to 1 microM) caused a concentration-dependent, noncytotoxic histamine release (greater than or equal to 10% of total) in 27 of 44 subjects tested (24 atopic and 20 nonatopic donors). The release process was either very rapid (t1/2 approximately equal to 10 s) or quite slow (t 1/2 approximately equal to 10 min), temperature- and Ca2(+)-dependent (optimal at 37 degrees C and 5 mM Ca2+). Coincubation of PAF with cytochalasin B (5 micrograms/ml) enhanced the release of histamine induced by PAF and activated the release process in most donors (42 of 44). Atopics did not release significantly more histamine than normal subjects, and the percentage of PAF responders (greater than or equal to 10% of total) was nearly the same in the two groups. Histamine release was accompanied by the synthesis and release of leukotriene C4, although this lagged 1 to 2 min behind histamine secretion. Lyso-PAF (100 nM to 10 microM), alone or together with cytochalasin B, did not release significant amounts of histamine. The release of histamine activated by PAF was inhibited by the specific PAF receptor antagonist, L-652,731, with an IC50 of 0.4 microM. There was a partial desensitization to PAF when the cells were preincubated with PAF (100 nM to 1 microM) for 2 min in the absence of Ca2+, whereas the cells remained responsive to anti-IgE (0.1 micrograms/ml). If neutrophils were removed from the basophil preparation by a Percoll gradient or a countercurrent elutriation technique, there was a significant decrease in PAF-induced histamine release. PAF (1 microM) was able to induce a very rapid, transient rise (peak less than 10 s) in [Ca2+]i in purified basophils analyzed by digital video microscopy. Finally, among human histamine-containing cells, the basophils are unique in degranulating following a PAF challenge. Mast cells from human lung, skin, or uterus failed to respond to PAF (10 nM to 1 microM) regardless of the presence or absence of cytochalasin B (5 micrograms/ml). Our results demonstrate that PAF is able to induce the release of inflammatory mediators from human basophils, and that neutrophils can influence this response. It is suggested that PAF-induced basophil activation can play a role in the pathogenesis of allergic disorders.

Antibodies, Anti-Idiotypic↗
PubMed1986

Comparative studies of mediator release from guinea pig lung mast cells and basophils.

Guinea pig lung mast cells and blood basophils were isolated and purified and their mediator release characteristics were compared. Upon stimulation with the antigen ovalbumin (OA) of cells passively sensitized with antiovalbumin (anti-OA) antibody, both cell types released histamine. The sensitivity and maximal response (20 to 25% histamine release) to OA was similar for both cells and was unaffected by cell purification. Antigen-induced histamine release (HR) was dependent upon added calcium to a similar extent (1 mM Ca++ maximal release) in both cell types; OA stimulation of passively sensitized mast cells also released leukotriene bioactivity (maximal release, 52 +/- 7 units/10(6) mast cells). There was no correlation between OA-induced leukotriene release and mast cell purity. No leukotriene bioactivity was detected in actively (sheep blood sensitization) or passively (anti-OA) sensitized basophils. Both lung mast cells and blood basophils released histamine in response to the secretagogues calcium ionophore A23187 and 12-O-tetradecanoylphorbol-13-acetate (TPA); TPA-induced HR from mast cells was independent of added calcium. In basophils, TPA-induced HR was only partially independent of added calcium. While both cell types were poorly responsive to the secretagogue 48/80, only the lung mast cell demonstrated inconsistent HR to concanavalin A (Con-A). Phosphatidylserine had no effect on HR provoked by antigen, Con-A, or compound 48/80. These observations demonstrate similarities and differences in mediator release characteristics between guinea pig lung mast cells and blood basophils that are similar to those observed with human lung mast cells and basophils. These observations also suggest a lack of influence on mediator release by other cell types present in dispersed lung cell and mixed leukocyte preparations.

Animals↗
PubMed1988

Regulation of human basophil and lung mast cell function by cyclic adenosine monophosphate.

Immunologic activation of purified human lung mast cells (HLMC) and basophils with anti-IgE induced histamine release but failed to elicit any changes in cAMP levels. In contrast, histamine release and monophasic rises in cAMP were observed in both rat peritoneal mast cells (RPMC) challenged with concanavalin A (73% enhancement over basal cAMP 20 sec after activation) and a cultured mouse bone marrow-derived mast cell (PT18 cell line) passively sensitized with dinitrophenol-specific IgE and stimulated with antigen (39% increase above basal at 15 sec). The adenylate cyclase activators isoprenaline, prostaglandin E2 (PGE2), and forskolin and the phosphodiesterase inhibitor isobutylmethylxanthine (IBMX) all induced elevations in cAMP levels in both basophils and HLMC. In basophils, PGE2 and isoprenaline produced approximately twofold increases in cAMP that were maximal at 1 min and decayed thereafter. Forskolin and IBMX produced threefold increases in cAMP that peaked 10 min after activation and persisted for up to 20 min. In HLMC, isoprenaline provoked a rapid monophasic fourfold increase in cAMP that was maximal at 1 min after addition. Levels of cAMP subsequently declined but remained significantly elevated over resting levels for up to 30 min. PGE2, forskolin, and IBMX all produced approximately threefold rises in HLMC cAMP that peaked around 5 min and persisted for 30 min. In both the basophil and HLMC, agonist-induced elevations in cAMP correlated well with the inhibition of mediator release. In basophils, the order IBMX greater than forskolin greater than PGE2 greater than isoprenaline held for both the inhibition of histamine and leukotriene C4 release and the augmentation of cAMP levels. In HLMC, individual agonists elevated cAMP levels to similar degrees and inhibited the release of histamine, leukotriene C4, and PGD2 to comparable extents, although the release of the arachidonate metabolites was generally more sensitive to the inhibitory actions of these agonists. These results suggest that elevations in cAMP, in both the basophil and HLMC, are associated with the inhibition of mediator release but not the initiation of the secretory process.

1-Methyl-3-isobutylxanthine↗
PubMed1988

Notes on the peroxidase activity of human basophil leukocytes.

In recent years, basophils have been described as peroxidase-positive in some textbooks (6, 8). However, as far as basophils in the peripheral blood from healthy persons are concerned, they must be considered as peroxidase-negative. This discrepancy is thought to be based on the following points: 1) fixation of human basophils is more difficult than that of the other leukocytes; 2) counterstaining with a certain basic dye causes misinterpretation of the enzyme reaction; 3) diaminobenzidine which has been most frequently used as hydrogen donor in the peroxidase reaction is so sensitive to non-enzymatic substances that substrate-minus experiments as well as inhibition experiments for peroxidase are absolutely necessary; and 4) basophils in the peripheral blood from healthy persons are originally peroxidase-negative. On the other hand, basophils in the peripheral blood from patients with myeloid leukemia are frequently peroxidase-positive, and yet, the peroxidase demonstrated in such basophils is not true myeloperoxidase since peroxidase from the above patients is resistant to heating, methanol and other chemicals known as inhibitors of myeloperoxidase. These data are illustrated by many color photographs.

Basophils↗
PubMed1989

IL-3-dependent growth of basophil-like cells and mastlike cells from human bone marrow.

Human bone marrow cultured in the presence of human rIL-3 has been reported to give rise to basophils. In contrast, mouse bone marrow, cultured in the presence of mouse IL-3, leads to the growth of mast cells. To determine if human rIL-3 might also stimulate the growth of human mast cells, we cultured human bone marrow in the presence of human rIL-3 in suspension cultures, methylcellulose, and in "interphase" cultures where cells are layered over agar. The presence of mast cells was determined using a variety of histochemical techniques. In agreement with previous reports, basophil-like cells were identified in all culture systems. Mastlike cells were identified only in interphase cultures. By 3 wk, such cultures consisted of basophil-like cells (20 to 50%) and mastlike cells (1 to 5%). Cultures supplemented with rIL-4 showed no additional increase in basophil-like and mastlike cells. Both basophil-like and mastlike cells fluoresced with o-phthaldialdehyde and exhibited IgE receptors. Unlike basophil-like cells, mastlike cells were chloroacetate esterase, amidase, and human mast cell tryptase positive. We conclude that human rIL-3 can support the growth of human mastlike cells under selected culture conditions.

Basophils↗
PubMed1989

Ultrastructure of eosinophils and basophils stimulated to develop in human cord blood mononuclear cell cultures containing recombinant human interleukin-5 or interleukin-3.

We used recombinant human interleukins (IL) and cultured human cord mononuclear cells to determine the cell lineages supported by the inclusion of the individual interleukins-5, -3, or -4 in the cultured media. Cultures were examined by electron microscopy at 2-, 3-, and 5-week culture intervals. We found that IL-5 primarily supported the eosinophilic lineage with lesser numbers of basophils, that IL-3 initially supported all granulocyte lineages but eventually supported the eosinophilic lineage with lesser numbers of basophils, and that IL-4 did not support the development of granulocyte lineages in these cultures. At early culture intervals in either IL-5 or IL-3, eosinophilic and basophilic myelocytes were seen in variable proportions. Mature cells of these lineages developed later. Both mature eosinophils and basophils showed morphologic evidence of activation similar to those described for tissue eosinophils and basophils in various disorders. Mast cells were absent in all cultures. Recognition of the variable morphologies associated with maturation and activation of human eosinophils and basophils is important for the correct identification of cell lineages that develop in cultures containing human recombinant interleukins.

Basophils↗
PubMed1988

Effects of a specific inhibitor of the 5-lipoxygenase pathway on mediator release from human basophils and mast cells.

We have characterized the effect of a specific inhibitor of the 5-lipoxygenase pathway on mediator release from human basophils and lung mast cells. In four experiments with purified basophils the phenothiazine derivative, L651-392, proved to be an effective inhibitor of leukotriene (LT) C4 release in the range 1-10 microM (P less than .005) although the release of histamine was unaffected by the highest doses of the drug. The release of 5-hydroxyeico-satetraenoic acid (5-HETE) from purified basophils (n = 2) was also reduced from 8.6 ng/10(6) basophils to below the limit of detection (1.2 ng/10(6) basophils). Intermediate concentrations of L651-392 (0.5 microM) reduced both the rate at which LTC4 was produced and the final concentration. The release of LTC4 was complete within 20-30 min and was unaffected by increased incubation periods (up to 90 min). HPLC analysis revealed that the drug was not promoting the metabolism of LTC4 to LTD4 or LTE4. Basophils (average purity = 78 +/- 3, n = 3) labeled with 3H-arachidonic acid (AA) were challenged with anti-IgE (0.1 microgram/ml) and the lipid mediators analyzed by HPLC. Control cells released 3H-LTC4, 3H-HETE, unmetabolized 3H-AA, and an unidentified metabolite, whereas those pretreated with L651-392 released only 3H-AA and the unknown metabolite with no detectable 3H-LTC4 or 3H-HETE. The specificity of the drug for the 5-lipoxygenase pathway was confirmed in three experiments with human lung mast cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Arachidonate 5-Lipoxygenase↗
PubMedDate not supplied

[Human basophil degranulation test. Results of a modified technic (I)].

The degranulation of human basophils towards antigenic substances, to which they must be previously sensitized as a result of the antigen-antibody union at the membrane level, is a phenomenon that has an important application complementing diagnosis of diseases mediated by the Gell and Coombs classification of Type I Hypersensitivity, on which the principle of Human Basophils Degranulation Test (HBDT) was based. An essential requirement is to be able to collect an adequate quantity of basophils, as well as the visualization by means of a technique of convenient stain. In this work, we show a modified HBDT technique for basophil granulocytes staining. A total of 33 HBDT was carried out on patients sensitive to grass pollen and/or Olea europea pollen and/or D. pteronyssinus, and as controls, HBDT was done on healthy individuals with negative clinical history. Basophil enrichemnt from the circulating blood sample was done by means of centrifugation in Percoll density gradients of 1072, 1076, 1080 and 1082, and we obtained a higher number of basophils with a density of 1080 at 400 Xg for 30 minutes. The cellular bottom was resuspended in 600 microliters of PBS. We employed lyophilized antigenic extracts from grass pollen, Olea europea and D. pteronyssinus, employing weight/volume concentration of 10(-4), 10(-5), 10(-6) and 10(-7). The optimum dilutions were 10(-5) for grass pollen and D. pteronyssinus.

Allergens↗
PubMed1985

Growth of human basophil lines derived from chronic myelocytic leukaemia cells in vitro: ultrastructure and X-ray microanalysis studies.

Mononuclear cells from the peripheral blood of patients with chronic myelocytic leukaemia were grown and expanded in liquid culture in the presence of Con A-conditioned medium. An accelerated development of cells of the basophilic lineage was observed and resulted in the appearance of 85% mature basophils after 14 days of incubation. Transmission electron microscopy of developing basophils showed changes in the nucleus and active granule formation in the cytoplasm. By scanning electron microscopy, the immature cells were relatively smooth in comparison with the mature basophils which showed membranous microvilli. The chemical content of the cells at different days of culture was detected by X-ray microanalysis. Immature cells were characterized by a high level of phosphorus with a low level of sulphur. As maturation progressed, the amount of phosphorus decreased, while the level of the sulphur increased, reaching its highest peak in the mature basophils. The different amount of sulphur found in the cells during the maturational process most probably represents the amount of heparin located in the cell granules. This finding may be useful for studying the influence of growth factors on the development and differentiation of human basophils.

Basophils↗
PubMed1982

Basophil releasability in the newborn: factors limiting immunoglobulin E-mediated histamine release.

Cord basophil preparations from 53 term neonates were studied for various factors affecting immediate hypersensitivity reactions including: basophil IgE receptor density and histamine releasability following incubation with calcium ionophore A23187, zymosan-activated serum (C5a), and anti-IgE. Basophil histamine content (geometric mean, 0.4 pg/basophil, with content in 14/28 cord blood samples below 0.2 pg/cell) is considerably below that of atopic and nonatopic individuals (geometric mean, 2.3 pg/basophil). Histamine release is normal with both A23187 (range 33% to 88%) and C5a (range 11% to 58%). Normal release with anti-IgE was shown in five of nine cord blood samples (range 13% of 52%), but four of five cell preparations required IgE preincubation. Indirect evidence indicates that basophils from newborns contain less than 30,000 total IgE receptors/cell. IgE-mediated histamine release in basophils from newborns is minimized by suboptimal IgE binding. Optimal IgE binding is not favored in basophils from neonates because of low serum IgE and low IgE receptor density. Serum IgE and IgE receptors increase to a variable degree as the child grows older and may determine the clinical onset of allergic disease.

Adult↗
PubMed1978

Sulfated glycosaminoglycans of guinea pig basophilic leukocytes.

Cytoplasmic granules of basophilic leukocytes stain metachromatically and have been thought to contain sulfated glycosaminoglycans, presumably heparin. To test this hypothesis, we identified the [35S]glycosaminoglycans synthesized by guinea pig blood basophils in culture and in vivo. Basophils isolated from guinea pig blood were cultured for 20 hr in F12 medium--10% guinea pig serum containing sodium [35S]sulfate. Alternatively, basophils were purified from animals receiving repeated i.v. injections of sodium [35S]sulfate. Glycoaminoglycans were isolated from these basophils after pronase digestion and identified by the use of selective glycosaminoglycan-degrading enzymes. Approximately 55% of the [35S]glycosaminoglycans was degraded by chondroitinase AC, indicating the presence of chondroitin sulfate; an additional 30 to 35% could be degraded by chondroitinase ABC, indicating that dermatan sulfate was also present. The 15% glycosaminoglycan remaining after chondroitinase ABC digestion was degraded by purified heparitinase (heparanase), which has no effect on authentic heparin but degrades heparan sulfate. Thus, the glycosaminoglycan content of guinea pig basophils is a mixture of chondroitin sulfate, dermatan sulfate, and smaller amounts of heparan sulfate. No heparin was detected.

Animals↗
PubMed1981

Flow-cytometric analysis of human basophil degranulation. III. Degranulation induced by allergens and antibodies in hay fever and bee venom allergic patients.

Human basophil degranulation responses to grass pollen and whole bee venom as allergens and to anti-IgE and anti-IgG4 as antibodies in hay fever and bee venom allergic patients were assessed using a flow-cytometric system. The concordance of basophil degranulation with skin tests and RAST assays reached more than 90%. These allergens and antibodies could degranulate basophils in a dose-dependent manner; however, there was a wide variation in the response of basophils obtained from different individuals. Moreover, a significant correlation was observed between the degree of degranulation by allergens and anti-IgE, or by allergens and anti-IgG4, but this was not the case between serum IgE concentrations and basophil response to anti-IgE. These data suggest that 'releasability' of basophils upon challenge by allergens and antibodies is also an important parameter in determining the degree of hypersensitivity in each subject.

Allergens↗
PubMed1980

[Clinical, morphological, cytochemical and ultrastructural studies of a female patient with basophilic leukemia].

The morphological, cytochemical and ultrastructural characteristics of basophilic cells in patients with chronic myeloleukosis were studied. The basophilic elements, dynamically followed up, from all phases of maturation, represented from 48 to 83 per cent of the cellular population in the peripheral blood and marrow. The cytochemical and ultrastructural investigations confirmed their belonging to the basophilic line. Certain changes were found, being an evidence of disorders in the maturation and metabolism of the cells. The high basophilic index, combined with a low neurophilic one, suggest the participation of the basophilic line in the leukosis process. On the base of the results obtained, the conception of the existence of basophilic leukosis is admitted.

Adult↗
PubMed1981

Surface membrane alterations in guinea pig basophils undergoing anaphylactic degranulation. A scanning electron microscopic study.

Purified guinea pig blood basophils in short-term tissue culture were studied by scanning and transmission electron microscopy and by 1-micrometer. light microscopic Epon sections after exposure to specific antigen (sheep serum), to guinea pig serum, or to serum-free medium at intervals from 1 minute to 48 hours. Basophils fixed before culture, or after culture in serum-free medium, were spherical cells with uniformly distributed microvilli, ridges, and folds. In cultures with guinea pig serum, basophils frequently assumed a hand mirror configuration, characteristic of motile cells, with a single posterior, microvilli-bearing uropod and anterior ruffles. Specific antigen induced basophils to become rounded, regardless of the culture medium, and resulted in basophil degranulation and histamine release within 5 to 20 minutes. Exposure of cytoplasmic granules to the external medium was initiated by the development, early in degranulation, of a single, 1 to 2 micrometer. in diameter, opening (degranulation pore) in the plasma membrane. The degranulation pore enlarged progressively over 24 to 36 hours, ultimately permitting the egress of membrane-free cytoplasmic granules. The cell pole opposite the degranulation orifice bore numerous prominent folds and ruffles, changes that persisted for at least 24 hours. By 48 hours after exposure to specific antigen (sheep serum), the surface features of basophils had reverted to those exhibited by unstimulated control cells.

Anaphylaxis↗
PubMed1993

Nimesulide, a sulfonanilide nonsteroidal anti-inflammatory drug, inhibits mediator release from human basophils and mast cells.

Nimesulide (NIM) is a sulfonanilide nonsteroidal anti-inflammatory drug (NSAID) used in the treatment of various inflammatory diseases and chemically unrelated to other acidic NSAIDs, such as acetylsalicylic acid (ASA) and indomethacin (INDO). We investigated the effects of NIM and of its in vivo metabolite, 4-hydroxy-NIM (OH-NIM), on the release of performed (histamine) and de novo synthesized mediators (sulfidopeptide leukotriene C4 [LTC4] and prostaglandin D2 [PGD2]) from human basophils and mast cells isolated from lung parenchyma (HLMC) and skin (HSMC). Histamine release from basophils challenged with rabbit anti-human IgE antibody (anti-IgE) was enhanced by preincubation with ASA or INDO (92.2 +/- 7.1% at 10(-3) M and 61.1 +/- 6.7% at 3 x 10(-6) M, respectively; P < .001). In contrast, NIM and its metabolite, OH-NIM (10(-6) to 10(-3) M), caused concentration-dependent inhibition (2.9 to approximately 60% and 3.7 to approximately 90%, respectively) of IgE-mediated histamine release from basophils. NIM and OH-NIM also inhibited histamine release from basophils induced by the Ca++ ionophore A23187 and different protein kinase C activators, such as 12-O-tetradecanoyl-phorbol-13-acetate, bryostatin 1 and bryostatin 5. NIM and OH-NIM also inhibited the IgE-mediated histamine release from HLMC (52.3 +/- 9.6% and 66.1 +/- 12.1% at 10(-3) M, respectively; P < .0001) and HSMC (67.3 +/- 3.7% and 77.7 +/- 12.0% at 10(-3) M, respectively; P < .0001) but had little or no effect on HLMC and HSMC activated by A23187. NIM (10(-6) to 10(-3) M) markedly inhibited the de novo synthesis of LTC4 from basophils, LTC4 and PGD2 from HLMC and PGD2 from HSMC. NIM and OH-NIM potentiated, whereas ASA and INDO reversed, the inhibitory effect of adenylate cyclase agonists, such as prostaglandin E1 and forskolin. In addition, NIM and OH-NIM reversed the enhancing effects of ASA and INDO on IgE-mediated histamine release from basophils.

Adolescent↗
PubMed1994

IgE-dependent IL-4 secretion by human basophils. The relationship between cytokine production and histamine release in mixed leukocyte cultures.

IL-4 protein and mRNA have recently been detected in pure basophil cultures after stimulation. It has also been established in mixed leukocyte cultures obtained by elutriation and challenged with anti-IgE that the basophil is the only cell that makes detectable IL-4. We have used cells prepared using Percoll gradients (5 to 30% basophils) to study the relationship between histamine release and IL-4 synthesis. In cultures challenged with anti-IgE after a 15-min pretreatment with IL-3, detectable IL-4 secretion ranged from 40 to 630 pg/10(6) basophils in 18 of 22 donors, with no significant correlation (r = 0.21, p = 0.34) with basophil purity. IL-4 synthesis was dissociated from histamine release, with optimal production consistently occurring at 10 ng/ml anti-IgE, whereas histamine levels peaked at 50 to 100 ng/ml of stimulus. Stimulation with anti-IgE alone was sufficient for IL-4 secretion but protein levels were enhanced two- to threefold in low responders by increasing the calcium concentration to 5 mM with no significant changes in histamine release. The IgE-independent secretagogues, F-met peptide (1 microM) and C5a (25 ng/ml), demonstrated limited ability to generate detectable IL-4, despite promoting vigorous histamine release. Additional studies showed no significant difference between IL-4 secretion in atopic and nonatopic donors. Finally, IL-4 levels generated with specific Ags were comparable to those levels produced in response to anti-IgE. We predict that basophil IL-4 generation will have a proinflammatory effect, but it appears that the signal transduction mechanisms for its synthesis and release differ from those for histamine release and thus may require different methods of pharmacologic control.

Basophils↗
PubMed1995

Standardization of allergenic extracts by basophil histamine release.

BACKGROUND: Allergenic extracts are standardized by using the ID50EAL (Intradermal Dilution for 50 mm sum of Erythema Determines the Allergy Unit) skin test technique to assign allergy units to reference preparations. When new batches of extracts are manufactured, they are compared with the reference by RAST inhibition or other in vitro techniques. This study was designed to determine whether basophil histamine release might be an additional useful in vitro test for the standardization of allergenic extracts. METHODS: Basophil histamine release, skin tests, and RAST were compared using several different allergenic extracts at many different strengths. Allergy units were calculated using skin test results and basophil histamine release. RESULTS: Basophil histamine release, skin tests, and RAST correlated well (P < .01). Basophil histamine release-derived allergy units and skin test-derived allergy units were highly correlated (P < .01). CONCLUSION: Basophil histamine release appears to be a useful tool for the standardization of allergenic extracts.

Allergens↗
PubMed1993

Infection of Nippostrongylus brasiliensis induces normal increase of basophils in mast cell-deficient Ws/Ws rats with a small deletion at the kinase domain of c-kit.

All basophils, mucosal-type mast cells (MMC) and connective tissue-type mast cells (CTMC) are derived from the multipotential hematopoietic stem cell. Mutations at the c-kit locus resulted in deficiency of MMC and CTMC in both mice and rats. To investigate the role of the c-kit receptor tyrosine kinase for production of basophils, we used white spotting/white spotting (Ws/Ws) mutant rats that have a small deletion at the tyrosine kinase domain of the c-kit gene. When Ws/Ws, nude athymic, and normal (+/+) rats were infected with Nippostrongylus brasiliensis (NB), the number of basophils increased greater than 50-fold in the peripheral blood of Ws/Ws and +/+ rats but did not increase in that of nude rats. Blood histamine concentration increased significantly in Ws/Ws and +/+ rats but did not increase in nude rats. Immature basophils increased greater than 10-fold in the bone marrow of Ws/Ws and +/+ rats but did not increase in that of nude rats. Mature and immature basophils that developed after the NB infection were identified by electron microscopy. The present result confirms that T-cell-derived cytokines are indispensable for the augmented production of basophils and suggests that stimulation via the c-kit receptor may not be necessary for the augmented production.

Animals↗