Antigenic competition in IgE antibody production. II. Effect of cyclophosphamide.

The effects of cyclophosphamide (CY) on antigenic competition in IgE antibody production were studied in mice treated with the drug on different days and immunized with a mixture of two non-related antigens. Injection of 100 mg of CY/kg of body weight 3 days before or 6 days after immunization resulted in a partial or total recovery of the IgE, but not of the IgGl antibody response to the test antigen. In contrast, when the same dose was given together or 3 days after immunization both responses were much more suppressed than in untreated animals. This same effect was obtained when a higher concentration (200 mg/kg) of cyclophosphamide was injected on day--3. When a different antigenic system was tested, the suppressive effects of competition in IgGl antibody production were also abolished after CY treatment. These results seem to provide further evidence for an important role of suppressor T cells in the mechanism of antigenic competition.     

Antigenic competition in IgE, IgG1 and IgG2 antibody production in the mouse

A comparative study of the effects of antigenic competition on the IgE, IgG1 and IgG2 antibody production was performed in mice immunized with two unrelated antigens. These antigens were injected as a mixture or in different sites. In addition, the groups of mice received one or three boosters of one or both antigens. The passive cutaneous anaphylaxis titres obtained in several bleedings showed a suppression of IgG1 and IgG2 antibody responses only in the groups injected with the two antigens in the same site, independently of antigenic boosters. The IgE antibody response was diminished when the antigens were given in a mixture, but this effect disappeared after a second booster. In contrast, groups injected with antigens separately started to show a suppressed response only at this time.     

Antigenic competition in IgE antibody production. I. Establishment of parameters involved in primary and secondary responses.

Antigenic competition was demonstrated in IgE antibody response in mice immunized with ovalbumin or DNP-ovalbumin associated with several non-related proteins: DNP-Ascaris, DNP-keyhole limpet haemocyanin or Ascaris. Simultaneous injection of two antigens caused a suppression of IgE antibody production to the test antigen, IgG1 antibody formation being only diminished under certain conditions. Competition was dose-dependent and effective only in the primary response. However, the secondary response could be also partially suppressed if the competitor antigen was given in both first and second antigenic stimulation. Competition was abolished by irradiation prior to immunization.     

Biological and immunological properties of Sugi basic protein-pullulan conjugate. I. Suppressive effect on IgE antibody production and on IgE-mediated reactions

Sugi basic protein (SBP), a major allergen of Japanese cedar pollen, conjugated to pullulan acquires suppressive activities for IgE, but not for IgG antibody production, and for IgE-mediated PK reactions in a SBP-specific manner. When either normal or IgE anti-SBP antibody-producing mice were treated with the conjugate, IgE anti-SBP antibody levels scarcely increased even after immunization with SBP + alum. This suppression was shown to be SBP specific and IgE selective. The ability of SBP-pullulan conjugate to elicit PK reactions on passively sensitized rat skin was markedly reduced. Furthermore, the conjugate inhibited the reactions mediated by the IgE antibodies and native SBP when it was injected into the IgE antibody-sensitized sites 2 h prior to SBP challenge. The reduced ability of the conjugate to elicit PK reactions was not due to loss of antigenic determinants during the conjugation procedures because binding activity of the conjugate to anti-SBP antibodies was as strong as that of native SBP. These results indicate that SBP-pullulan conjugate may be useful for 'desensitization therapy' against the pollinosis.     

Dendritic cells suppress IgE production in B cells

Ig class switch recombination (CSR) is triggered by the engagement of CD40 on B cells by CD40 ligand on T cells. In addition, recent studies have shown that dendritic cells (DCs) are able to directly control the CSR of B cells through B lymphocyte stimulator protein [or B cell activation factor belonging to the tumor necrosis factor family] and a proliferation-inducing ligand. We examined in this study the regulatory role of DCs in CSR and demonstrate that DCs selectively suppress IgE production from B cells stimulated by CD40 and IL-4 through two different mechanisms: by direct cell-cell interaction or by soluble factors including transforming growth factor-beta and IFN-gamma. In addition, distinct DCs utilize different mechanisms: immature bone marrow-derived dendritic cells (BMDCs) and primary lung DCs strongly inhibit IgE CSR. On the other hand, LPS-induced mature BMDCs lose the ability to inhibit IgE CSR but still suppress IgE production by decreasing IgE protein expression. These results indicate novel regulatory functions of DCs on IgE production.     

Suppressive effects of mometasone furoate on an antigen-specific IgE antibody response and production of IL-4 in mice

A nasal formulation of mometasone furoate (MF) is advantageous in avoiding systemic activity characteristic of glucocorticoids when it is applied topically. To confirm antiallergic effects of this glucocorticoid formulation elaborately, we investigated whether the drug can suppress the production of IgE antibodies and related cytokines. It we showed that IgE production induced in mice immunized via intranasal route was significantly reduced when the mice were administered MF intranasally. Further, MF was effective in inhibiting production of type-2 helper T cell cytokines in vivo and in vitro. These results provide a immunopharmacological basis for clinical efficacy of this drug.     

Further studies on the adjuvant effect of silica on IgE antibody production in mice.

The effects of amorphous silica (Aerosil) and of aluminium hydroxide on anti-DNP IgE antibody production were studied in Swiss mice preimmunized with Ascaris protein and then challenged 7 days later with DNP-ASC. Aerosil exerted an adjuvant effect especially when it was injected together with the DNP-ASC conjugate. Al(OH)3 had a weaker adjuvant effect than that produced by Aerosil and then only when it was injected with the DNP-ASC conjugate. Al(OH)3 given with Ascaris extract 7 days before complete antigen had an inhibitory effect on the anti-DNP IgE antibody production.     

Age-related changes in specific IgE antibody production.

We measured specific IgE antibodies to mites and Japanese cedar pollen (JCP) in a general population aged from 18 to 99 years by fluorescence enzyme immunoassay and analyzed the relationship of antigen-specific IgE antibody production to aging. The incidence of mite antibody carriage gradually decreased in proportion to age from 26.7% at 18 to 19 years of age to 15.9% for the 60 to 69 age group and then decreased markedly in the subjects aged 70 and over. A similar tendency was found with regard to JCP antibody positivity. The highest levels of antibodies to both mites and JCP were found in young adults, and these levels decreased with age. There was a significant negative correlation between the mean relative fluorescence unit value for specific IgE antibodies and age (mite antibody: r = -.957 and JCP antibody: r = -.954). No significant correlation was found between mite antibody levels and JCP antibody levels in the individual subjects.     

Relation between total serum IgE levels and IgE antibody production in rats.

Five different rat strains were immunized with 100 microgram ovalbumin and 1 mg Al (OH)3. A good correlation was found between the total serum IgE level of a rat strain before immunization and the IgE antibody production. Good IgE antibody-producing strains had high total serum IgE levels and vice versa. A discordance between the evolution of the total serum IgE level after immunization and the changes in IgE antibody level was found in all strains.     

Regulation of the IgE antibody response in mice. II. Radioresistance of established IgE antibody production.

The protracted IgE anti-ovalbumin (OA) response given by BDF1 mice was studied using an adoptive transfer model. Spleen cells taken from immunized BDF1 mice can produce IgE antibody in irradiated recipients without further overt antigenic challenge. Depletion of macrophages in active spleen cell suspensions did not diminish the capacity of the remaining cells to give an adoptive response. Evidently the cells subserving the adoptive response are not fully developed in donor mice until 4 weeks after immunization, since spleen cells removed at shorter intervals after immunization gave either no or weak adoptive responses. The production of IgE antibody in irradiated recipient mice is prevented if transferred B or T lymphocytes are treated in vitro with either gamma irradiation or mitomycin C, suggesting proliferation of both B and T lymphocytes is essential for the adoptive response to develop. However, the requirement for proliferation is only transient, since one IgE antibody production reached a steady state in the adoptive recipients, it manifested extreme resistance to high dose irradiation. Whole body irradiation of 800 and 1000 rad was without effect on sustained IgE production. This latter observation was valid for both intact mice which were irradiated 8 weeks after immunization and also for irradiated adoptively immunized mice. It is suggested that the IgE anti-OA antibody measured in serum of BDF1 mice several months after immunization with 1 microgram OA and 1 mg Al(OH)3 is the product of long-lived antibody secreting cells.     

Suppressive effect of bone marrow cells of normal and leukemic mice on antibody production by spleen cell cultures in vitro

The suppressive activity of bone marrow cells from AKR and (CBA×C57BL)F₁ mice aged 2 and 10 months in relation to the primary immune response of spleen cells to sheep's red blood cells in vitro was investigated. In leukemic AKR mice the suppressive activity of the bone marrow was shown to rise considerably until the 9th–10th month compared with that at the age of 2 months. In (CBA×C57BL)F₁ mice the suppressive activity of bone marrow at these same times was unchanged.Institute of Biophysics, Ministry of Health of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR R. V. Petrov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 1, pp. 36–38, January, 1980.     

Antigen dose-dependent differences in IgE antibody production are not due to polarization towards Th1 and Th2 cell subsets

The quality of the humoral immune response against protein antigens in CBA/J mice is dependent on the antigen dose used for immunization: low doses induce high titers of IgE antibodies, whereas high doses promote the production of IgG2a antibodies but inhibit IgE formation. To investigate whether the reciprocal regulation of antibody production is possibly due to a differential activation of Th1 and Th2 cell populations in the two immunization groups, the cytokine pattern of spleen cells from both groups, cultured with antigen in vitro, was analyzed by measurement of intracellular and secreted cytokine levels. The data presented show that in vitro restimulated spleen cells from mice primed with low as well as with high doses of antigen produce predominantly the Th2 cytokines IL-4 and IL-10 but reduced levels of IL-12. The release of IFN-γ is only slightly enhanced compared to unstimulated control cultures. The results indicate that CD4⁺ T cells in both groups belong mainly to the Th2 cell subset. This finding is contradictory to the general allegation that the antigen dose is decisive for the polarization of Th1 versus Th2 immune responses and shows that the antigen dose-dependent regulation of IgE antibody production is not due to differential polarization towards Th1 and Th2 cells.     

Enhancing effect of suspended particulate matter on the IgE antibody production in mice

Suspended particulate matter (SPM), suspended in the polluted environmental atmosphere, are perpetually inhaled into the human body and are considered to have profound effects on human health. This study investigated the enhancing effect of SPM on the IgE antibody production in mice. The IgE antibody responses in mice immunized with intranasal administration of ovalbumin (OA) plus SPM at 3-week intervals were higher than responses in the animals immunized with OA alone. When the dose of OA administered as an antigen was 0.25 microgram, the time course and magnitude of enhancement by SPM was comparable to those by killed Bordetella pertussis, a common adjuvant. SPM had an enhancing effect on IgE antibody production even in a small dose such as 0.25 microgram administered at 3-week intervals. The possibility cannot be excluded that the natural exposure of humans to SPM in the environmental atmosphere may explain the high prevalence rate of allergic rhinitis caused by pollens in polluted districts in Japan.     

Suppressive effect of IgE soluble immune complex on neutrophil chemotaxis

The effect of IgE soluble immune complex (SIC) and IgG SIC on neutrophil chemotaxis was investigated. Eight types of SIC were prepared from kappa type IgE myeloma protein and IgG myeloma protein: IgE-anti-kappa SIC in IgE excess and in anti-kappa excess, IgE-anti-epsilon SIC in IgE excess and in anti-epsilon excess, IgG-anti-kappa SIC in IgG excess and in anti-kappa excess, IgG-anti-gamma SIC in IgG excess and in anti-gamma excess. Four types of IgE SIC markedly suppressed neutrophil and chemotaxis, but free IgE, free anti-kappa chain antibody, free anti-epsilon chain antibody and IgG SIC had no inhibitory activity. This inhibitory activity of IgE SIC on neutrophil chemotaxis was cell directed and concentration-dependent. IgE immune complex also inhibited neutrophil chemotaxis when immune complex was formed in the neutrophil chemotaxis.     

Studies on antigenic competition: III. Effect of antigenic competition on antibody affinity*

The effect of antigenic competition on antibody affinity was studied using a haptenic system in guinea-pigs. A moderate depression in the amount of antibody formed, as a result of antigenic competition, had relatively little effect on affinity. Increasing the dose of the competing antigen resulted in a greater degree of competition. Under these conditions a large amount of low affinity antibody was produced by the animals while essentially no high affinity antibody was detectable. Thus, marked competition appeared to result in a failure to select for high affinity antibody synthesis.     

Antigenic competition between dengue and Coxsackie viruses for presentation to B cells by macrophages

Macrophages (M phi) pulsed with dengue type 2 (DV) and Coxsackie B4 (CoxB) viruses present antigen to B lymphocytes leading to their clonal expansion as detected by counting antigen-specific IgM antibody plaque-forming cells (PFC). The present study was undertaken to investigate the site for competition in M phi between the two heterologous antigens, DV and CoxB, for their presentation to B cells. It was observed that DV-pulsed M phi presented antigen to B cells in mice depleted of T cells by treatment with anti-Thy 1.2 monoclonal antibodies. The B cells could not be stimulated in absence of M phi in mice treated with silica. The PFC counts for both the antigens were inhibited when M phi were pulsed simultaneously with DV and CoxB. PFC counts were increased by 53-120% by predigesting the antigens by trypsin. Inhibition of DV-specific response by CoxB was abrogated by predigesting CoxB. A marked reduction in DV-specific PFC response was observed when CoxB was superimposed on M phi pulsed with DV 24 h earlier. CoxB-specific PFC counts were not affected by superimposing DV on M phi pulsed with CoxB 24 h earlier. PFC response to the antigen given to M phi before glutaraldehyde fixation was not affected while that for the antigen given to glutaraldehyde-fixed M phi was markedly depressed. It is concluded that the competition between DV and CoxB for antigen presentation to B cells occurs in M phi at the level of antigen processing.