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Group 2 innate lymphoid cells (ILC2s) produce a significant amount of interleukin-5 (IL-5), which supports eosinophil responses in various tissues; they also produce IL-13, which induces mucus production and contributes to tissue repair or fibrosis. The ILC2s are activated by alarmins, such as IL-33 released from epithelia, macrophages and natural killer T (NKT) cells in response to infection and allergen exposure, leading to epithelial injury. We examined gene expression in lung ILC2s and found that ILC2s expressed Ifngr1, the receptor for interferon-γ (IFN-γ). Interferon-γ severely inhibited IL-5 and IL-13 production by lung and kidney ILC2s. To evaluate the effects in vivo, we used α-galactosylceramide (α-GalCer) to induce NKT cells to produce IL-33 and IFN-γ. Intraperitoneal injection of α-GalCer in mice induced NKT cell activation resulting in IL-5 and IL-13 production by ILC2s. Administration of anti-IFN-γ together with α-GalCer significantly enhanced the production of IL-5 and IL-13 by ILC2s in lung and kidney. Conversely, cytokine production from ILC2s was markedly suppressed after injection of exogenous IL-33 in Il33(-/-) mice pre-treated with α-GalCer. Hence, IFN-γ induced or already present in tissues can impact downstream pleiotropic functions mediated by ILC2s, such as inflammation and tissue repair., (© 2015 John Wiley & Sons Ltd.)

Using T-cell receptor (TCR) transgenic mice, we demonstrate that TCR stimulation of naive CD4(+) T cells induces transient T-bet expression, interleukin (IL)-12 receptor beta2 up-regulation, and GATA-3 down-regulation, which leads to T helper (Th)1 differentiation even when the cells are stimulated with peptide-loaded I-A(b)-transfected Chinese hamster ovary cells in the absence of interferon-gamma (IFN-gamma) and IL-12. Sustained IFN-gamma and IL-12 stimulation augments naive T-cell differentiation into Th1 cells. Intriguingly, a significant Th1 response is observed even when T-bet(-/-) naive CD4(+) T cells are stimulated through TCR in the absence of IFN-gamma or IL-12. Stimulation of naive CD4(+) T cells in the absence of IFN-gamma or IL-12 with altered peptide ligand, whose avidity to the TCR is lower than that of original peptide, fails to up-regulate transient T-bet expression, sustains GATA-3 expression, and induces differentiation into Th2 cells. These results support the notion that direct interaction between TCR and peptide-loaded antigen-presenting cells, even in the absence of T-bet expression and costimulatory signals, primarily determine the fate of naive CD4(+) T cells to Th1 cells.

Interleukin (IL)-5 induces CD38-activated splenic B cells to differentiate into immunoglobulin M-secreting cells and undergo micro to gamma 1 class switch recombination (CSR) at the DNA level, resulting in immunoglobulin G1 (IgG1) production. Interestingly, IL-4, a well-known IgG1-inducing factor does not induce immunoglobulin production or micro to gamma 1 CSR in CD38-activated B cells. In the present study, we implemented complementary DNA microarrays to investigate the contribution of IL-5-induced gene expression in CD38-stimulated B cells to immunoglobulin-secreting cell differentiation and micro to gamma 1 CSR. IL-5 and IL-4 stimulation of CD38-activated B cells induced the expression of 418 and 289 genes, respectively, that consisted of several clusters. Surprisingly, IL-5-inducible 78 genes were redundantly regulated by IL-4. IL-5 and IL-4 also suppressed the gene expression of 319 and 325 genes, respectively, 97 of which were overlapped. Genes critically regulated by IL-5 include immunoglobulin-related genes such as J chain and immunoglobulinkappa, and genes involved in B-cell maturation such as BCL6, activation-induced cytidine deaminase (Aid) and B lymphocyte-induced maturation protein-1 (Blimp-1) and tend to be induced slowly after IL-5 stimulation. Intriguingly, among genes, the retroviral induction of Blimp-1 and Aid in CD38-activated B cells could induce IL-4-dependent maturation to Syndecan-1+ antibody-secreting cells and micro to gamma 1 CSR, respectively, in CD38-activated B cells. Taken together, preferential Aid and Blimp-1 expression plays a critical role in IL-5-induced immunoglobulin-secreting cell differentiation and micro to gamma 1 CSR in CD38-activated B cells.

The effector CD8(+) T cells recognize major histocompatibility complex (MHC) class I binding altered self-peptides expressed in tumour cells. Although the requirement for CD4(+) T helper type 1 (Th1) cells in regulating CD8(+) T cells has been documented, their target epitopes and functional impact in antitumour responses remain unclear. We examined whether a potent immunogenic peptide of Mycobacterium tuberculosis eliciting Th1 immunity contributes to the generation of CD8(+) T cells and to protective antitumour immune responses to unrelated tumour-specific antigens. Peptide-25, a major Th epitope of Ag85B from M. tuberculosis preferentially induced CD4(+) Th1 cells in C57BL/6 mice and had an augmenting effect on Th1 generation for coimmunized unrelated antigenic peptides. Coimmunization of mice with Peptide-25 and ovalbumin (OVA) or Peptide-25 and B16 melanoma peptide [tyrosinase-related protein-2 (TRP-2)] for MHC class I led to a profound increase in CD8(+) T cells specific for OVA and TRP-2 peptides, respectively. This heightened response depended on Peptide-25-specific CD4(+) T cells and interferon-gamma-producing T cells. In tumour protection assays, immunization with Peptide-25 and OVA resulted in the enhancement of CD8(+) cytotoxic cell generation specific for OVA and the growth inhibition of EL-4 thymoma expressing OVA peptide leading to the tumour rejection. These phenomena were not achieved by immunization with OVA alone. Peptide-25-reactive Th1 cells counteractivated dendritic cells in the presence of Peptide-25 leading them to activate and present OVA peptide to CD8(+) cytotoxic T cells.

Background: There has been no study of the clinicopathologic features of patients with hepatocellular carcinoma (HCC) who are seropositive for lectin-reactive alpha-fetoprotein (AFP-L3) alone, or seropositive for AFP-L3 and seronegative for des-gamma-carboxy prothrombin (DCP) in comparison with those who are seropositive for DCP alone. Thus, the present comparative study was performed., Methods: The clinicopathologic features of HCC patients with either one or two tumors who underwent a hepatectomy (n = 88) were compared among the following five groups according to the seropositivity of AFP, AFP-L3 and DCP: (i) group A, seropositive for AFP above 100 ng/mL, AFP-L3 above 15% and DCP above 100 mAU/mL; (ii) group B, seropositive for AFP-L3 and seronegative for DCP below 40 mAU/mL; (iii) group C, seronegative for AFP below 20 ng/mL, AFP-L3 below 15% and seropositive for DCP; (iv) group D, seropositive for AFP and seronegative for AFP-L3 and DCP; and (v) group E, seronegative for AFP, AFP-L3 and DCP., Results: Group B patients showed a higher incidence of infiltrative-type HCC with an irregular margin (P < 0.05) and a higher frequency of poorly differentiated HCC (P < 0.01) compared with group C patients. Group A patients had larger tumors and more massive-type tumors than group B patients. Our HCC cases showed that advanced clinicopathologic features were demonstrated in the order of group B, group C and group D. Group A and B patients and group D and E patients showed similar characteristics., Conclusions: Hepatocellular carcinoma patients who were seropositive for AFP-L3 and seronegative for DCP demonstrated clinicopathologic features of more advanced HCC compared with those who were seropositive for DCP alone., (Copyright 2002 Blackwell Publishing Asia Pty Ltd)

Background: There has been no comparative study of the clinicopathological features of HCC patients who are seropositive for alpha-fetoprotein (AFP) alone and those who are seropositive for des-gamma-carboxy prothrombin (DCP) alone. The authors, thus, performed this comparative study., Methods: The clinicopathological features of patients with solitary hepatocellular carcinoma (HCC), who underwent a hepatectomy were compared among the four below groups according to the seropositivity of AFP and DCP: group A, seronegative for both AFP below 20 ng/mL and DCP below 40 mAU/mL; group B, seropositive for AFP above 100 ng/mL and seronegative for DCP; group C, seronegative for AFP and seropositive for DCP above 100 mAU/mL; and group D, seropositive for both AFP and DCP., Results: Group B patients showed a higher incidence of HCC with an indistinct margin, and a somewhat higher incidence of small HCC less than 2 cm in greatest dimension compared with group C patients. By contrast, group C patients had a higher frequency of HCC with a distinct margin compared with that of an indistinct margin, large tumors more than 3 cm compared with that of small tumors less than 2 cm, and a somewhat higher frequency of moderately to poorly differentiated HCC compared with that of well-differentiated HCC. Our HCC cases showed advanced clinicopathological features in the order of group C, group B and group A. Groups C and D patients showed similar characteristics., Conclusions: Hepatocellular carcinoma patients who were seropositive for AFP alone demonstrated clinicopathological features of less advanced HCC compared with those who were seropositive for DCP alone.

The interleukin-5 receptor alpha chain (IL-5Ralpha) is known to regulate the development and function of B cells and eosinophils. Although the functions of IL-5Ralpha cytoplasmic domain subregions have been studied extensively using cultured cell lines, this approach has limitations when studying the functions of distinct primary B-cell subpopulations and their responsiveness to IL-5. In the present study, we generated mice on an IL-5Ralpha null background, each expressing a mutant form of an IL-5Ralpha transgene ligated to a mu enhancer and VH promoter, either lacking the cytoplasmic DC3 region or substituting two proline residues for alanine (ApvA) in the membrane-proximal ppvp motif of the cytoplasmic domain. The ppvp motif, which mediates activation of JAK2/STAT5 and Btk, also contributes to c-fos, c-jun and c-myc expression. IL-5Ralpha null mutant mice showed impaired B-1-cell development, reduced serum immunoglobulin G3 (IgG3) and IgM, no IL-5-induced enhancement of B-cell proliferation and IL-5-induced switch recombination from the mu gene to gamma1 gene; these were not recovered following the expression of the ApvA mutant. In contrast, absence of the DC3 region affected the IL-5-induced switch recombination from the mu to the gamma1 gene and B-1-cell development, while IL-5-induced proliferation and IgM production were at levels similar to those of B cells expressing wild-type IL-5Ralpha transgene. The results clearly indicated that the ppvp motif and the DC3 region of IL-5Ralpha played distinct roles in B-cell proliferation and differentiation. Thus, this present approach offers new insights into the functions of the cytoplasmic subregions of IL-5Ralpha, in particular its carboxy-terminal region.

Objective: The role of IL-5 receptor alpha chain (IL-5Ralpha) in the onset of bronchial hyperresponsiveness (BHR) to acetylcholine was investigated by testing IL-5Ralpha knockout (IL-5Ralpha KO) mice., Methods: Mice were immunized with antigen at intervals of 12 days. Starting 10 days after the secondary immunization, mice were exposed to antigen three times every fourth day. Twenty-four hours after the last antigen challenge, bronchial responsiveness to acetylcholine was measured and bronchoalveolar lavage was carried out., Results: Twenty-four hours after the last antigen inhalation, total and differential cells counts of bronchoalveolar lavage revealed a significant increase in eosinophils and lymphocytes in ovalbumin-exposed wild-type mice. In IL-5Ralpha KO mice, there was little increase of eosinophils in bronchoalveolar lavage fluid (BALF). The production of IL-5 in BALF increased in both mice after repeated antigen challenge, and there was no significant difference between wild-type and IL-5Ralpha KO mice. Similar to the BAL study, histological sections of lung tissue from ovalbumin-exposed wild-type mice exhibited airway eosinophilic inflammation, which was attenuated by the deficiency of IL-5Ralpha chain. There was no significant difference in serum antigen-specific IgE levels between wild-type and IL-5Ralpha KO mice after immunization nor antigen inhalation. Repeated antigen provocation caused BHR to acetylcholine in wild-type mice. In contrast, no BHR was observed in IL-5Ralpha KO mice after repeated inhalation of antigen., Conclusion: These findings indicate that IL-5Ralpha plays an important role in the development of antigen-induced airway eosinophilia and BHR in mice.

Human memory (CD45RO+) CD4+ T cells can be distinguished into two subpopulations on the basis of expression of the lymph node homing receptor, L-selectin (CD62L). In a prior study we showed that human L-selectin-positive memory T-helper (Th) cells promote the maturation of IgG- and IgA-producing cells by naive B cells. To further elucidate the contribution of memory CD4+ T cells to B-cell differentiation, human memory CD4+ T cells with or without L-selectin expression were evaluated for production of cytokines that participate in regulation of immunoglobulin production. It was found that L-selectin-positive human memory CD4+ T cells produce mainly interleukin (IL)-4 and IL-5, whereas L-selectin-negative CD4+ T cells produce mainly interferon-gamma (IFN-gamma). This profile of cytokine expression coincides with the profile that distinguishes Th1 and Th2 subsets. In contrast to the murine system, IL-10 production was similarly contributed by human L-selectin-positive and -negative memory CD4+ T-cell subpopulations. These results suggest that the human L-selectin-negative and -positive subpopulations of human memory CD4+ T cells contain Th1-like and Th2-like cytokine-producing cells, respectively.

A novel monoclonal antibody (mAb) was established in an attempt to look for a cell-surface molecule that delivered a signal regulating apoptotic cell death of B cells. Because spleen cells in resting culture die from apoptosis, mAb were looked for that were able to prolong spleen cell survival in vitro. This screening selected mAb CS/2. CS/2 not only prolonged spleen cell survival in vitro, but also protected spleen cells from apoptotic cell death brought about by irradiation or dexamethasone. Moreover, stimulation of spleen cells with CS/2 mAb induced changes of cells to blastoid morphology, and a significant uptake of [3H]thymidine ([3H]TdR). The antigen recognized by CS/2 mAb (CS/2 Ag) was expressed on preB cells, B cells, and Mac-1+ cells. The cells surviving in vitro culture or irradiation in response to ligation with CS/2 mAb were mostly B cells expressing the CS/2 Ag. In addition, B cells from X-linked immunodeficient (XID) mice did not respond to CS/2 mAb. These results indicate that CS/2 mAb is agonistic to B cells, and that XID mice are deficient in this CS/2 mAb-mediated activation pathway. Determination of the amino-terminal 24 amino acid residues revealed that the CS/2 Ag appears to be identical to the CS/2 mAb is directed against a murine CD38 homologue, and suggest a possible role of the murine CD38 homologue in controlling apoptotic cell death of B cells.

We studied cells in the lungs of BALB/c and BALB/c-nu/nu (nude) mice infected with Toxocara canis, which produced interleukin-5 (IL-5) in in vitro culture with larval excretory-secretory antigen (ESAg). The proportion of CD4+/CD8+/CD4- CD8- cells in lungs of both BALB/c and nude mice was unchanged before and after infection with T. canis. Panning and complement-mediated lysis using monoclonal antibody (mAb) to CD4 showed that CD4+ cells in the lung from both mice produced IL-5. Anti-CD4 mAb suppressed ESAg-stimulated IL-5 production in vitro. In vitro depletion or inhibition of CD8+ cells reduced IL-5 production significantly in some cases, suggesting involvement with IL-5 production. Anti-CD3 mAb enhanced IL-5 production when incubated with or without ESAg. Production of IL-5 was reduced by in vivo depletion of CD4+ cells only and both CD4+ and CD8+ T cells, by intraperitoneal injection with appropriate mAb; IL-5 production was stimulated by anti-CD3 mAb. In contrast, IL-5 production by lung cells of BALB/c mice decreased by more than 90% after simultaneous injection with anti-CD4, anti-CD8 and anti-CD3 mAb, and was not enhanced by anti-CD3 mAb. Similar results were obtained in nude mice. These results suggest that CD4- CD8- T cells, as well as CD4+ T cells, produce IL-5.

We studied the mechanism of eosinophilia in BALB/c-nu/+ (nu/+) and BALB/c-nu/nu (nu/nu) mice infected with Toxocara canis. Eosinophilia with two peaks on days 11 and 21 of infection was observed in infected nu/+ mice, and with a peak on day 11 in nu/nu mice. Interleukin-5 (IL-5) mRNA was expressed on day 5 of infection in the lung and spleen of nu/+ mice and in the lung of nu/nu mice, but not in the spleen of nu/nu mice. Large numbers of eosinophils and lymphocytes infiltrated the lung of both mice 1 week after infection. The number of larvae in the lung was the largest on day 5. Anti-IL-5 monoclonal antibody (mAb) treatment completely inhibited eosinophilia of both mice, with no change of larval distribution. Administration of anti-CD4 or anti-CD3 mAb markedly reduced the second peak of eosinophilia on day 21 of infection in nu/+ mice, and slightly reduced the first peak of eosinophilia on day 11 in both mice. Anti-CD8 mAb had no effect on the eosinophilia. These results suggest that eosinophilia in both mice is caused by IL-5, and that IL-5 is produced by cells other than CD4+ T cells, in addition to CD4+ T cells.

We depleted or neutralized interleukin-5 (IL-5) and IL-5 receptor of C57BL/6 mice, using rat anti-murine IL-5 monoclonal antibody (NC17) and anti-murine IL-5 receptor monoclonal antibody (H7). Mice treated with these monoclonal antibodies were infected with Strongyloides venezuelensis larvae. The time-course of faecal egg output and peripheral eosinophilia were monitored. In a primary infection, anti-IL-5 treatment did not affect faecal egg output, although the eosinophil count in peripheral blood was markedly reduced. There was no difference in intestinal worm burden or faecal egg output between anti-IL-5 treated and non-treated mice. In a secondary infection, worms were expelled from the small intestine of anti-IL-5-treated mice as well as from non-treated mice. Worm recovery from the lungs of mice treated with either anti-IL-5 or anti-IL-5 receptor monoclonal antibody was the same as that of normal controls. However, a marked reduction in worm recovery was observed in re-infected mice that had not been treated with monoclonal antibodies. Treatment with anti-IL-5 or anti-IL-5 receptor monoclonal antibody suppressed blood and tissue eosinophilia. Thus the results suggested that the host's protective immunity against tissue-migrating larvae was IL-5-dependent but intestinal immunity was not.

Two distinct murine B-cell differentiation factors, designated B151-TRF1 and B151-TRF2, were described originally as B151K12 T-cell hybridoma-derived lymphokines that induce immunoglobulin (Ig) secretion by antigen-activated B cells and unstimulated B cells, respectively. In the present study, we found that a highly purified B151-TRF1 fraction prepared by reversed-phase high-performance liquid chromatography (RP-HPLC) also has the ability to cause a polyclonal differentiation of unstimulated B cells into IgM-secreting cells in the apparent absence of co-stimulant. The activity of the B151-TRF1 fraction but not the B151-TRF2 fraction on unstimulated B cells was markedly inhibited by addition of a monoclonal antibody (mAb) specific for the B151-TRF1/IL-5 to the culture. To determine whether B151-TRF1/IL-5 and B151-TRF2 act on distinct populations among unstimulated B cells, the responsiveness of neonatal B cells and adult B cells that had been fractionated by Percoll density gradient centrifugation was assessed. B151-TRF1/IL-5 predominantly acted on lower density B cells, which appeared around 3 weeks after birth in the spleen. In contrast, B151-TRF2 could activate both lower and higher density B cells almost equally and B151-TRF2-responsive B cells were already present by 1 week of age. Thus, these results suggest that B151-TRF1/IL-5 and B151-TRF2 act on distinct subpopulations among antigen-unprimed normal B cells to induce IgM-secreting cells.

We established three functionally distinct purified protein derivative (PPD)-reactive T-cell clones (B11.15, B12.F and D-2). Clone B11.15 could co-operate with DNP-primed B cells to induce anti-DNP IgG plaque-forming cell (PFC) responses only when high amounts of PPD were added to the culture, whereas stimulation of a low amount of DNP-PPD was ineffective (factor-mediated interaction). On the other hand, clone D-2 activated those B cells in a MHC-restricted manner only when DNP-PPD was added to the culture (cognate interaction). B12.F could stimulate B cells with either PPD or DNP-PPD. Antigen non-specific helper factors (lymphokines) responsible for B-cell activation produced by cloned T cells upon stimulation with PPD and antigen-presenting cells were then investigated. Lymphokine activities determined in the present study were IL-2, BCGF I, BCGF II and TRF. BCGF I activity was determined by proliferation-inducing activity on purified B cells in the presence of anti-IgM antibody. BCGF II activity was measured by proliferation-inducing activity on purified B cells in the presence of dextran sulphate. TRF activity was determined on DNP-primed B cells for inducing further differentiation into anti-DNP IgG PFC. BCGF I active molecules were eluted in the fraction at apparent MW of 50,000-70,000 and 8,000-10,000 in gel-permeation column chromatography.

The B-cell differentiation-inducing activity of interleukin-1 (IL-1) was compared with that of T-cell replacing factor (TRF)/interleukin-5 (IL-5), which was originally described as a late-acting B-cell differentiation-inducing factor. Human recombinant IL-1 and murine recombinant TRF/IL-5 were used in this study. Purified B cells from non-primed or antigen-primed mice, LPS-stimulated B-cell blasts, and chronic B-cell leukaemia (BCL1) cells were used as the responding B-cell population. Addition of IL-1 to the culture of normal B-cells and sheep red blood cells (SRBC) induced a dose-dependent anti-SRBC IgM response, with maximal response at 100 U/ml, whereas the response induced by TRF/IL-5 was less than that induced by IL-1 and did not reach the maximum even at 100 U/ml. Addition of anti-IL-1 antibody, but not anti-TRF/IL-5 antibody or anti-IL-2 receptor antibody, inhibited IL-1-induced anti-SRBC responses. Depletion of cells adherent to Sephadex beads from splenic B cells showed no significant effect on the magnitude of the total responses. IL-1 could induce little, if any, differentiation in antigen-primed B cells, LPS-stimulated B-cell blasts, or BCL1 cells into antibody-secreting cells, whereas differentiation could be induced by low doses of TRF/IL-5 (1-2 U/ml). Of great interest is that suboptimal doses of IL-1 (10 U/ml) could synergize with TRF in the primary anti-SRBC PFC responses. Kinetic studies revealed that IL-1 acts on B cells for the first 2 days and TRF/IL-5 for the last 3 days in 5-day cultures of B cells. These results suggest that IL-1 acts primarily on resting B cells as a differentiation-inducing factor in the presence of antigen, and also acts as a 'priming' factor for TRF/IL-5.

There is a body of evidence suggesting that IgA production is regulated by helper T cells or their products. To elucidate molecular mechanisms of IgA production, the role of lymphokines in the in vitro antigen-specific and polyclonal IgA responses was examined. Supernatants from antigen-stimulated T cells or mitogen-stimulated T-cell clones can enhance 2,4-dinitro phenyl (DNP)-specific IgM, IgG1 and IgA production in cultures of DNP-ovalbumin (OVA)-stimulated T-cell-depleted spleen cells from DNP-keyhole limpet haemocyanin-primed mice. The IgA enhancement was inhibited by anti-IL-5 monoclonal antibody. Purified recombinant IL-5 could also enhance anti-DNP IgA production in a dose-dependent manner. This enhancing effect was not substituted by IL-1, IL-2, IL-3 or IL-4. Polyclonal IgA secretion of lipopolysaccharide-stimulated normal B cells was augmented preferentially by IL-5, but not by IL-4. Surface IgA-positive (sIgA+) B cells, but not surface IgA-negative B cells, responded to IL-5 for the development of IgA-secreting cells. Limiting-dilution analysis revealed that IL-5 increases the frequency of IgA-secreting cells in sIgA+ B-cell populations. These results indicate that IL-5 plays an essential role in the antigen-specific and polyclonal IgA formation as a maturation-inducing factor rather than class-switching factor.