V. Holford-Strevens

The relationship between smoking and total immunoglobulin E levels

Results of skin testing to common allergens, total serum IgE levels, and the responses to a respiratory questionnaire were obtained for 1768 individuals participating in a survey of a rural population. The geometric mean total IgE levels in a group of subjects without skin-test reactions and with no histories of asthma or hay fever was 14.8 U/ml for men and 11.9 U/ml for women. When individuals were classified according to skin reactivity and smoking history there was a significant difference in IgE levels among nonsmokers, exsmokers, and smokers, with smokers having the highest levels. The percentage of subjects with elevated total IgE levels was higher in smokers than in nonsmokers regardless of skin reactivity to common allergens. Among smokers there was no relationship between intensity and duration of smoking and IgE levels. Among exsmokers IgE levels tended to be lower in those who had stopped smoking earlier.

Serum total immunoglobulin E levels in Canadian adults

A history of respiratory and allergic disorders was obtained in a white, rural population with ages 20 to 65 yr. Allergy skin testing was performed, and total IgE was measured by PRIST method. One thousand eight hundred and fourteen subjects were studied. Those subjects with positive allergic skin reactions and a history of allergic disorders and smoking were excluded to provide a reference group to derive normal values of total IgE. The mean level of the total IgE of this reference group was 12.1 U/ml. The upper limit of the normal range of total IgE levels was estimated at 87.3 U/ml. IgE levels did not differ between the sexes or with age in our adult population.

Tolerogenic polyethylene glycol derivatives of xenogeneic monoclonal immunoglobulins

It is becoming apparent that the effectiveness of xenogeneic monoclonal antibodies (XIg), which are increasingly used for diverse therapeutic purposes in man, may be counteracted by their inherent immunogenicity. Since conjugates of proteins with monomethoxypolyethylene glycol (mPEG) have proved to be effective tolerogens in other systems, we have used an experimental model in mice to explore the tolerogenicity of mPEG conjugates of a human monoclonal IgG (HIgG), i.e. a myeloma protein. Administration of these conjugates prior to immunization with heat aggregated HIgG (ha-HIgG) resulted in specific tolerance, as manifested by a marked reduction in the level of antibodies to HIgG, which was related to the degree of conjugation and the dose of conjugate administered. Thus, administration of HIgG(mPEG)20 6 to 43 days prior to immunization with ha-HIgG resulted in an inhibition of anti-HIgG antibody formation of the order of 85-90%, in relation to the titres of mice receiving PBS in lieu of HIgG(mPEG)20; these results hold the promise that mPEG conjugates of XIg may prove therapeutically useful in man in relation to organ transplantation, localization of tumours by immuno-imaging and tumour destruction by immunotoxins.

Tumor-reactive IgE antibodies in plasma of patients with gastrointestinal carcinomas

SummaryA total of 208 plasma samples from 115 patients with gastrointestinal carcinomas and nine patients with other intestinal disease were examined for the presence of IgE tumor antibodies by a solid-phase radioimmunoassay. Approximately one-third of the patients gave significant reactions with gastrointestinal carcinoma extracts compared with normal tissue extracts. Absorption with tumor and normal tissue extracts, with type AB human red cells, and with CEA indicated tumor specificity in some of the samples so examined. None of the 50 serum samples tested from normal blood donors contained tumor-specific IgE. IgE tumor antibodies decreased or completely disappeared in the majority of patients 8–13 days after surgical treatment.

Down-regulation of secondary in vitro antibody responses by suppressor T cells of mice with treated with a tolerogenic conjugate of ovalbumin and monomethoxypolyethylene glycol, OVA(mPEG)13

In previous studies from this laboratory it was shown that OVA(mPEG)n conjugates induced: (i) tolerance in mice with respect to IgG and IgE antibody responses to dinitrophenylated OVA (DNP-OVA); and (ii) OVA-specific suppressor T (Ts) cells which could down-regulate a primary immune response in vivo. For the present study, we have developed an in vitro culture system for assessing the activity of Ts cells of mice tolerized by an OVA(mPEG)13 conjugate. Spleen cells from mice which had been primed with DNP4-OVA in Al(OH)3 gel were cultured with DNP4-OVA to induce a secondary antibody response in vitro. After 6 days, cells secreting anti-DNP antibodies of the IgG1 class were enumerated by an immunoenzymatic plaque-forming cell assay. Addition to the culture of T cells from mice treated with 3 i.p. injections of 500 micrograms of OVA(mPEG)13 resulted in a 29-61% reduction in the number of IgG1 anti-DNP antibody-forming cells, in comparison with the effect of T cells from mice treated with PBS. It was concluded that this tolerogenic conjugate induced splenic Ts cells which were capable of suppressing secondary in vitro anti-DNP responses.

Downregulation of helper T cells by an antigen-specific monoclonal Ts factor

The findings of previous studies in this laboratory demonstrating that conjugates of human monoclonal (myeloma) IgG (HIgG) and monomethoxypolyethylene glycol (mPEG) were able to induce in mice antigen-specific tolerance and CD8+ suppressor T (Ts) cells were confirmed in the present study. An extract (TsF) of a nonhybridized clone of Ts cells (viz., clone 23.32), which had been derived from spleen cells of mice tolerized with HIgG(mPEG)26, was shown to possess antigen-specific suppressive activity. This monoclonal TsF was able to specifically suppress in vitro antibody formation only if it was present from the beginning of the culture. From the results of the cellular dissection of the system used it was concluded that (i) the TsF had no effect on fully differentiated primed B cells or plasma cells, and (ii) the TsF inactivated carrier-primed Th cells when the culture contained concomitantly naive CD8+ T cells, accessory cells, and antigen. These data support the view that the monoclonal TsF exerted its downregulating effect on Th cells only if it could first interact with a CD8+ T cell, in the presence of accessory cells and antigen.

Induction of in vivo helper activity for murine antibody responses by macrophages pulsed with ovalbumin-monomethoxypolyethylene glycol (OA-mPEG) conjugates

Conjugates of protein antigens with an optimal number of monomethoxypolyethylene glycol (mPEG) chains of an appropriate molecular weight had been shown to suppress murine IgE responses to the unmodified antigen. To investigate the possibility that the tolerogenic capacity of these mPEG conjugates is attributable to a defect in macrophage (M phi) presentation of their antigenic determinants, the activity of ovalbumin (OA)-mPEG conjugates when pulsed onto mouse peritoneal adherent cells (M phi) was compared in this study with their activity in solution. Surprisingly, in contrast to the suppressogenic capacity of mPEG conjugates in solution, the OA-mPEG pulsed M phi appeared to exert a helper effect when injected intraperitoneally (ip), i.e., after subsequent immunization with dinitrophenylated OA (DNP3-OA) in Al(OH)3, the mice showed accelerated IgE and IgG1 antibody responses to OA and DNP. However, when M phi were exposed to limiting concentrations of OA or OA-mPEG, markedly higher concentrations of OA-mPEG were required to yield pulsed M phi, exerting a significant helper effect. It was concluded that although M phi were capable of presenting the OA determinants of OA-mPEG conjugates to helper T (Th) cells, the preparations of modified antigen were presented less effectively than native OA.

Suppression of the Murine Anti-Trimellityl (TM) IgE Response: Induction of B Cell Tolerance by Conjugates of TM and Polyvinyl Alcohol

It was previously shown that administration of conjugates of trimellitic anhydride with polyvinyl alcohol (TM-PVA) could suppress the IgE anti-TM immune response of mice sensitized with a TM-ovalbumin conjugate. In the present study, the existence of TM-specific B cell tolerance was shown by cell transfer experiments in which splenic B cells from mice treated with TM-PVA failed to interact with either the helper T (Th) cells of carrier primed recipients or with Th cells derived from carrier-primed donors. In contrast to previous findings from this laboratory indicating that tolerogenic conjugates of PVA and the 2,4-dinitrophenyl group led to both B cell tolerance and activation of suppressor T (Ts) cells, no evidence was obtained for the induction of Ts cells by TM-PVA. Thus, the induction of demonstrable Ts cells by hapten-PVA conjugates may depend on some property conferred by the haptenic group.