Antigenic competition in IgE antibody production. III. Suppressive effect on Th and B cells

An adoptive cell transfer system was utilized to evaluate the site of action of the suppressive mechanism involved in antigenic competition in IgE antibody production. Carrier-primed (OA) and hapten-primed (DNP-KLH) spleen cells were transferred to syngeneic irradiated recipients that were challenged with a heterologous conjugate (DNP-OA). To study the effect of antigenic competition on T and B cells, donor mice of one or the other cell type received in addition the competitor antigen (Asc) at immunization. The adoptive secondary IgE anti-DNP antibody response was suppressed in both situations. This effect could not be attributed to transfer of Asc-primed cells. Irradiation of donor mice before immunization with the two antigens abrogated the suppressive effect. These results indicate that both Th and B cells primed to the test antigen were affected by antigenic competition.     

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.     

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.     

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.     

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.     

Relationships between IgE antibody production and other immune responses. II. Effect of thymectomy at various times after birth

Mice were subjected to thymectomy at various times after birth and immunized with ovalbumin in aluminum hydroxide gel at 4 or 8 weeks of age. The capacities to produce IgE, IgM and IgG antibodies were abolished by thymectomy carried out within 48 h after birth. The capacity to produce IgE antibody was not affected by thymectomy at 7 days or later, whereas the capacities to produce IgM and IgG antibodies were reduced by thymectomy carried out at 4 weeks of age.     

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.     

Rat IgE production. II. Primary and booster reaginic antibody responses following intradermal or oral immunization.

Primary and booster IgE antibody responses have been elicited in Hooded Lister rats by the intradermal injection or oral administration of very small quantities of egg albumin. Oral immunization was effected by giving antigen by stomach tube or in the drinking water. The minimum primary dose of antigen found to be effective was 1 mug intradermally and 10 mug orally, administered together with an intraperitoneal injection of B. pertussis adjuvant. In rats immunized with these doses secondary responses could be evoked by giving even smaller quantities of antigen, thus 1 ng intradermally or 1 mug orally without adjuvant. Smaller challenge doses were not tried. Large primary doses of antigen (greater than 100 mug) presented by these routes were, on the other hand, found to be inhibitory to the production of secondary IgE responses, this effect being similar to that observed in previously reported intraperitoneal immunization experiments. By contrast with previous experiments, however, tertiary responses could be obtained following immunization by these routes, and we believe this to be reflection of the absorption of smaller and therefore less inhibitory quantities of antigen. Our results are discussed in relation to the control of IgE antibody production, current concepts of the control of antigen absorption through mucosal barriers, and possible implications of the genesis of naturally occurring IgE responses in man.     

IgE synthesis in man. II. Comparison of tetanus and diphtheria IgE antibody in allergic and nonallergic children.

Specific IgE and IgG antibodies were quantitated in 91 allergic and 80 nonallergic age- and sex-matched children between 4 and 17 yr of age. Statistically significant increased antidiphtheria and antitetanus IgE antibodies (p < 0.01) measured by the radioallergosorbent test (RAST) were noted in allergic compared with nonallergic subjects. Of the allergic children with total serum IgE >500 U/ml, 19 of 52 (37%) and 25 of 52 (48%) had elevations (>2 SD above nonallergic control mean) of serum antitetanus or antidiphtheria IgE antibody, respectively, whereas only 2 of 35 allergic children with serum IgE <500 U/ml had elevation (>2 SD) of these antibodies. Antitetanus and antidiphtheria IgG antibodies were measured by passive sheep red blood cell (SRBC) hemagglutination. Geometric mean antitetanus IgG antibodies were higher in allergic (4.9 AU/ml) as compared to nonallergic (1.7 AU/ml) children (p < 0.001). Geometric mean antidiphtheria IgG antibodies were higher (0.31 AU/ml) in nonallergic and lower in allergic (0.10 AU/ml) subjects (p < 0.01). These data suggest that allergic individuals with markedly elevated total serum IgE have unique antibody responses following routine immunization with tetanus-diphtheria (Td) toxoids and tetanus-pertussis-diphtheria (DPT) which are manifest by enhanced specific IgE synthesis.     

Effect of multiple injections of antigen on prolonged IgE antibody production in hypersensitive mice

Multiple injections of ovomucoid were given to mice with ongoing prolonged IgE antibody production to that antigen. Two inbred strains and antigen doses ranging from 0.05 to 5 μg each injection, given intradermally and subcutaneously, were used. Mice treated in this manner showed a marked diminution of the IgE antibody booster response as compared to controls. This decrease in booster response was antigen-specific. In addition, a protective effect from anaphylaxis was indicated. The mouse model continues to be a valuable tool for studies of certain IgE-mediated diseases.     

Enhancement of IgE antibody production by ovalbumin aerosol in mice

The effect of aerosolized ovalbumin (OA) on the induction of IgE antibody production was investigated in BALB/c mice. Enhancement of anti-OA IgE antibody production was obtained after the administration of 10 micrograms OA in mice preexposed to 1% aerosolized OA for 6 or 30 min, and after the administration of 1 microgram OA in mice preexposed to aerosolized OA for 30 min. IgE antibody production could also be induced by preexposure to aerosolized OA at a concentration as low as 0.1%. A carrier effect was observed by preexposure to aerosolized OA using a hapten-carrier system. In the latter system, whole body irradiation (200 R) could not enhance IgE response, suggesting that irradiation-sensitive suppressor T cells might be generated in insufficient amount or not at all by aerosolized OA. Preexposure to aerosolized dinitrophenol-OA could not enhance anti-dinitrophenol IgE response. These results suggest that the exposure to aerosolized antigen primed preferentially T helper cells.     

In vitro production of IgE by human peripheral blood mononuclear cells. II. Cells involved in the spontaneous IgE production in atopic patients

Spontaneous IgE production in vitro was investigated in 7-day cultures of unfractionated mononuclear cells (MNC) and MNC subpopulations from atopic patients. Depletion of either phagocytic or adherent cells decreased the amount of IgE detectable in 7-day culture supernatants, but this decrease was due, at least in part, to a loss of cytophilic IgE. Depletion of immunoglobulin-bearing cells (SIg⁺) reduced significantly but did not abolish the spontaneous IgE production in vitro. On the other hand, depletion of IgM-bearing lymphocytes (SIgM⁺), which virtually abolished the production of immunoglobulins of the IgM class, did not change significantly the spontaneous production of IgE. Similarly, no change in the spontaneous production of IgE was found when lymphocyte suspensions were depleted of complement receptor-bearing cells (CR⁺). In contrast, spontaneous IgE production was significantly increased by depletion of T lymphocytes and this increase did not simply reflect the enrichment for IgE-producing cells caused by the fractionation procedure. No significant change in the spontaneous IgE production was found when small numbers of autologous T lymphocytes were added to B cell fractions, whereas the addition of higher concentrations of autologous T cells induced a marked inhibition of the spontaneous IgE production. On the other hand, the addition in culture of pokeweed mitogen (PWM) resulted in a marked reduction of the spontaneous IgE production by B cells, also in the presence of small concentrations of autologous T lymphocytes. Normal T cells were consistently effective in inducing a partial inhibition of the spontaneous IgE production by B cells from atopic patients, whereas T cells from a noticeable proportion of atopic patients were not. These data suggest that MNC responsible for the spontaneous IgE production in atopic subjects are SIgM- and CR-deficient well-differentiated lymphocytes which probably represent the result of an activation which has occurred in vivo. However, this spontaneous IgE production can still be influenced by in vitro manipulation, such as variations in T–B cell ratios or addition of PWM. The results here reported also indicate that normal T cells are generally more effective than T cells from atopic patients in regulating the activity of spontaneous IgE-producing cells present in the blood of atopic subjects.     

Rat IgE production: I. Effect of dose of antigen on primary and secondary reaginic antibody responses

The experiments described here form part of a series carried out to determine the conditions of antigen presentation which dispose to the production of IgE antibody in the rat. We have found that Hooded Lister rats in comparison with rats of some other strains have an exceptional ability to produce reaginic antibodies: responses can be consistently induced with very small doses of antigen and are boosted to high levels with a second dose of antigen.

The effect of the dose of antigen on these responses is as follows.

     

Regulation of secondary antibody responses in rodents. I. Potentiation of IgG production by cyclophosphamide.

This paper describes the effects of a single dose of cyclophosphamide on specific IgG production in rats during an established secondary immune response. (PVG X Agus)F1 rats were immunized twice (days 0 and 28) with chicken erythrocytes (CRBC), received cyclophosphamide (100 mg/m2 of body surface area) on day 33 and were killed 8 days later. The production of anti-CRBC IgG antibodies was assessed by testing the supernatants of spleen cell cultures in a cytotoxicity assay with 51Cr-labelled CRBC as target cells and normal rat spleen cells as effector cells. In observations of fifty-nine pairs of treated and untreated rats from eight separate experiments, the administration of cyclophosphamide resulted in: (1) a decrease in the number of spleen cell to a median of 10(8.63) from a median of 10(8.7) (P less than 0.0025); (2) an increase in the anti-CRBC IgG antibody titre of the supernatants of cultured spleen cells to a median of 10(0.67) from a median of 10(0.27 (P less than 0.0025); and (3) the calculated anti-CRBC. IgG antibody production per spleen to be increased in the drug-treated rats to a median of 10(2.26) from a median of 10(2.0) (P less than 0.005). In a cyclophosphamide dose-response study, it was shown that some enhancement of antibody production was induced by doses between 12.5 and 50 mg/m2 and consistently elevated levels of antibody production were associated with doses between 100 and 400 mg/m2.     

Suppression of IgE antibody production after exposure to ozone in mice

The effect of ozone exposure on IgE antibody production with aerosolized ovalbumin (OA) administration was investigated in Balb/c mice. Mice were continuously exposed to 0.8 ppm ozone for 1, 2, or 4 weeks, respectively, and subsequently aerosolized OA was administered through the respiratory tract for 6 min with a nebulizer. The mice were then immunized intraperitoneally 1 week later with OA. IgE antibody production was suppressed in ozone-exposed mice. However, no significant difference in the primary IgE antibody production by intraperitoneal immunization alone with OA was observed between ozone-exposed mice and nonexposed mice. In order to elucidate the suppressive mechanism of IgE antibody production, hapten-carrier antigenic system was used. It is shown that the induction of helper T cell function was suppressed if the aerosolized carrier protein was administered before intraperitoneal immunization in the mice exposed to ozone. These results suggest that ozone exposure has the effect on the stage of administration of inhaled antigen and the quite insignificant effect on the IgE antibody production after intraperitoneal immunization with OA.     

Genetic dependence of IgE antibody production in mice infected with the nematode Nippostronglyus brasiliensis. I. Modulation of the IgE antibody response in vivo by serum factors

We investigated the IgE-antibody response in 36 inbred mouse strains during infection with Nippostrongylus brasiliensis. With regard to the N. brasiliensis-specific IgE-antibody activity responder and nonresponder mice were obtained. Mice with the H-2-f haplotype (A.CA, B10.M, A.TFR 5) are high specific responders. It is suggested that one Ir gene for the N. brasiliensis-induced IgE-antibody response is localized within the K to J region of the mouse major histocompatibility complex. To obtain a medium IgE-antibody response it appears that a complementation between two Ir genes is necessary. An additional genetic control beyond the H-2 complex cannot be excluded. As to the total nonspecific serum IgE levels the parasitic infection leads to a 20- to 40-fold increase in high and low specific responder strains as well. Pretreatment of high responder mice (A.TFR 5, B10.M) with sera that were obtained from normal or complete Freund's adjuvant treated low (B10.G) and nonresponder (A.TFR 1) mice led to significant inhibition or enhancement of the N. brasiliensis-specific IgE-antibody response.