Anti-Thy-1 antibody provokes reverse passive cutaneous anaphylaxis-like reactions.

Antibodies to rat Thy-1, and also to murine Thy-1, could provoke reverse passive cutaneous anaphylaxis-like (RPCA-like) reactions. The threshold amount of purified anti-Thy-1 antibodies for RPCA-like reactions was 12.5 microg/ml. No RPCA-like reactions were obtained with IgG1 F(ab')2 anti-Thy-1. Cross-linking the murine anti-rat Thy-1 F(ab')2 fragments with goat antibody against murine F(ab')2 anti-rat Thy-1 permitted us to obtain RPCA-like reactions with as little as 1.5 microg/ ml. However, when the cross-linking was done with the F(ab')2 of the same goat antibody, no RPCA-like reactions were obtained. The antibody against rat FcepsilonRIalpha or its F(ab')2 product were equally effective in producing RPCA-like reactions; the threshold was obtained with 1.5 microg/ml. The mechanism of the difference is discussed.

IgE memory B cells identified by the polymerase chain reaction.

The existence of memory B cells for IgE was investigated using spleen cells harvested from mice primed and boosted with dinitrophenylated keyhole limpet hemocyanin. Using the polymerase chain reaction, it was found that mRNA for IgE was already demonstrable in spleen cells taken 1 day after boost. Spleen cells taken from mice 1 day after boost and cultured in vitro without the addition of antigen also produced anti-dinitrophenylated (DNP) IgE antibody. In contrast, mRNA for IgE in spleen cells from mice primed 4 weeks previously, but not boosted, was not demonstrable. Anti-DNP IgE was not produced in cultures of spleen cells from mice primed but not boosted. As mRNA for IgE was demonstrable already 1 day after boost we concluded that mice produce memory B cells not only for IgM, but also for IgE specific for the immunizing antigen.

IgE allotypes in sera of mice with autoimmune diseases and in mice with graft-versus-host disease after transfusion or bone marrow transplantation.

Isotype- and allotype-specific IgE determinations by sandwich ELISA with monoclonal antibodies to Igh-7 (6HD5, HMK-12), Igh-7a (No. 297) and Igh-7b /JKS-6) were used to qualitate antibodies of the IgE class. The sensitivity of the method is 0.1 ng/ml. Serum IgE levels were much higher in mice infected with Nippostrongylus brasiliensis. In sera of BALB/c, AKR and C3H/JCL mice only IgEa, in sera of C57BL/6 and CB-20 only IgEb, in sera of (BALB/c x C57BL/6) F1 mice, both allotypes were detected, as expected. In mice with autoimmune diseases, such as NZB, NZW, (NZB x NZW) F1, MRL/Ipr and MRL/n strains which all belong to the IgEa allotype group, IgE and IgEa were very high. In the sera of BXSB mice, both IgEa and IgEb were detected. Both IgEa and IgEb from donor and host were increased in the sera of mice with graft-versus-host disease after transplantation but only the IgEa (from the donor) was increased in mice with graft-versus-host disease after bone marrow transplantation. In the former, both B cells (from donor and host) secreted IgE, whereas in the latter only the donor cells did. These are the first observations showing the importance of IgE allotype secretion as an indication of graf-versus-host disease.

Anaphylactic IgE and IgG1 production for hapten can be enhanced by contrast media.

Various side effects have been associated with the clinical use of contrast media. Immunological mechanisms have been proposed but there have been very few experimental studies with animal models. We have attempted to develop murine models to determine whether or not anaphylactic antibodies such as IgE and IgG1 against hapten (DNP) were enhanced with contrast medium (iopamidol) as an adjuvant or if the contrast medium itself produced antibodies of the IgE class. The results showed that anti-hapten IgE and IgG1 production was greatly enhanced with immunogen plus contrast medium. Anti-contrast medium antibodies of the IgE class could not be detected by PCA reactions. The enhancement of IgE and IgG1 production for hapten was associated with IL-4 release by the neutralization test used by monoclonal anti-IL-4 antibodies. This is the first observation to show that contrast media may have a strong adjuvant effect for the production of IgE and IgG1. This murine model demonstrates a possible immunological function of contrast media in vivo.

Anti-IL-4 antibody prevents graft-versus-host disease in mice after bone marrow transplantation. The IgE allotype is an important marker of graft-versus-host disease.

Induction of a graft-vs-host reaction in irradiated (BALB/c X C57BL/6)F1 mice (CBF1 mice) with bone marrow cells (BMC) plus spleen cells of BALB/c mice leads to bone marrow transplantation--GVHD (BMT-GVHD). BMT-GVHD is characterized by liver disease, splenomegaly, and hypergammopathy. In addition, we found that increased serum IgE and IgG1 levels were correlated with BMT-GVHD such as liver disease and splenomegaly. The allotype of increased IgE levels in BMT-GVHD was IgEa of donor origin, not IgEb of host origin. We also found that in the thymus of murine BMT-GVHD, the CD4+ CD8+ double-positive T cells were decreased, but the CD4+ CD8- or CD4- CD8+ single-positive T cells were increased. Interestingly, double-positive T cells appeared in the spleen, suggesting that abnormal T cell differentiation existed in murine BMT-GVHD. When the recipients were treated with anti-IL-4 Ab (11B11), the increase of IgE and IgG1 was markedly reduced and liver disease and splenomegaly were also prevented. Moreover, abnormal T cell differentiation and maturation were suppressed. These observations suggest that IL-4 plays an important role in immunoregulation or pathogenesis of allogeneic effects, and 11B11 prevents immunodysfunction including T cell differentiation in the thymus or the spleen and autoimmune symptoms in murine BMT-GVHD.

Immediate hypersensitivity. A brief, personal history.

The discovery of anaphylaxis by Portier and Richet that reinjection of a substance caused disease instead of immunity was sensational as it was against the prevailing DOGMA. Passive transmission of hypersensitivity with human antibody by Prausnitz (the P-K reaction, 1921) was an important step in the study of human hypersensitivity. Anaphylaxis was shown to be the consequence of liberation of vasoactive substances (histamine and SRS-A) from mast cells when the allergen crosslinks two IgE molecules fixed to mast cell Ig receptors (Ovary, 1961). The use of smooth muscle contraction (Dale, 1913) and vascular permeability increase (PCA, Ovary, 1948) became important for experimental studies. The clonal selection of antibody formation (Burnet, 1929) opened a new era in immunological concepts. The demonstration of the Fc receptor on mast cells (Ovary, 1961) called attention to the importance of cellular receptors. The carrier effect (Ovary & Benacerraf, 1963) was explained by recognition by T cell receptors of a processed carrier fragment complexed to Ia molecules (Unanue, Grey, 1981). Human IgE responsible for allergies was discovered in 1965 by K. & T. Ishizaka. Tonegawa in 1973 destroyed the "one gene-one protein" DOGMA, showing that the immunoglobulin, germline gene is discontinuous: i.e., composed of exons (which will form the Ig molecule) separated by introns. The CD4 cells were subdivided into Th1 and Th2 cells (Mosmann & Coffman, late 1980's). The Th2 secretes IL-4 necessary for IgE production (Paul, Vitetta, & others, early 1980's). B cells multiply before antibody production or become memory B cells, but what causes a B cell to become a memory cell is not known. The B cell does not change specificity but can switch the isotype using "switch recombinase" and the s segment of the Ig molecules (Honjo, early 1980's). IgE production was shown to be suppressed by lymphokines, such as IFN-gamma and IL-2. A great progress in understanding the mechanism of allergic reaction has been the result of intense investigations by many scientists. A more complete understanding, better prophylaxis and an improved treatment are the goals of the near future.

Murine IgG1 and IgE memory B cells.

Anti-dinitrophenyl IgG1 and IgE antibody production were examined in vitro. Splenic B cells from mice immunized in vivo at various intervals with dinitrophenylated proteins were cultured in vitro with splenic T cells and splenic antigen-presenting cells from mice immunized previously (2 weeks) with keyhole limpet hemocyanin. Anti-dinitrophenyl IgG1 and IgE antibodies were determined in the supernatants by ELISA. Without T cells and antigen-presenting cells or without antigen, no anti-dinitrophenyl antibodies were detected. When the B cells were separated by panning with anti-murine IgG1 antibody, only the cells adhering to anti-IgG1 produced anti-dinitrophenyl IgG1 antibodies. Anti-dinitrophenyl IgE production was observed from cells adhering and from cells not adhering to the anti-IgG1-coated plates, as expected. However, anti-dinitrophenyl IgE was also produced from cells which adhered to the anti-IgG1-coated plates, but did not have surface IgE antibodies. Therefore, cells without surface IgE adhering to anti-IgG1 were capable of producing anti-dinitrophenyl IgE antibodies.

Suppression of IgE production in unseparated spleen cell cultures.

When B cells from BALB/c mice were cultured with lipopolysaccharide (LPS) and interleukin-4 (IL-4), a large amount of IgE was detected in the culture supernatants. The IgE production from unseparated spleen cells cultured with LPS and IL-4 was less than the amount of IgE obtained from separated B cells. When syngeneic T cells were added to separated B cells cultures, which were subsequently stimulated with LPS and IL-4, less IgE was produced, as compared to cultures without T cells. The hypothesis that T cells, or factors secreted by these cells, inhibit IgE production is supported by the fact that the degree of suppression of IgE production paralleled the number of T cells added. CD8(+)-enriched T cells were slightly more suppressive than CD4(+)-enriched T cells. Addition of exogenous IL-3 was only partially suppressive. These observations suggest that IL-4 added to unseparated spleen cells in vitro stimulates B cells for IgE production and also stimulates T cells. Lymphokines secreted by these stimulated T cells may in turn act on B cells. Some of these lymphokines, such as interferon-gamma and IL-2, may have a suppressive action on IgE production.

Acquired resistance to Schistosoma japonicum in IgE-deficient SJA/9 mice immunized with irradiated cercariae.

Participation of IgE in protective immunity against Schistosoma japonicum was examined by comparing congenital IgE-deficient SJA/9 and IgE-producing SJL/J mice. Mice immunized with 100 irradiated cercariae 7 weeks previously were infected with 50 live cercariae. In SJL/J mice at 40 days after infection, a 3-to 4-fold increase of total IgE levels and anti-S, japonicum egg IgE antibody production were observed with no significant difference between immunized and nonimmunized mice. IgE was not detected in SJA/9 mice throughout the experiments. Protective immunity evaluated by recovery of adult worms was found in SJA/9 mice and was comparable to that of SJL/J mice. These results suggest that acquired immunity in mice with irradiated cercariae of S. japonicum was not dependent on IgE in these strains of mice.

Primary anti-trinitrophenyl memory cells investigated by plaque-forming cells and ELISA.

Primary anti-trinitrophenyl antibody production was investigated from spleen cells of mice immunized with trinitrophenylated-keyhole limpet hemocyanin, using the plaque-forming cell method and ELISA. Cells taken 5 days after antigen injection do not produce IgE, but do produce IgM and IgG1 anti-trinitrophenyl antibodies as demonstrated by plaque-forming cells. Substantial increase of IgM, IgG1, and IgE antibody production was seen from cells taken 7 days after immunization, followed by a rapid decline. By ELISA it was seen that cells taken 3 days after immunization already produce small amounts of anti-trinitrophenyl antibodies. Presence of antigen from the start of the cultures did not increase antibody production from cells taken 3 days after immunization, but potentiated antibody secretions from cells taken 5 days or later after immunization. This potentiation was interpreted as recruitment of antibody-forming cells from early memory B cells. The presence of IL-4 from the start of the cultures had no appreciable effect. Cell sorting with specific antibody-coated magnetic beads showed that plaque-forming cells from nonsorted cells, membrane IgE+ or membrane IgE- cells secreted similar amounts of anti-trinitrophenyl IgG1 and IgE antibodies. No difference in anti-trinitrophenyl IgM, IgG1, or IgE production was found in controls; cells sorted negatively or positively for CD23. The data show that memory B cells can be demonstrated already on Day 5 after immunization, and their antigen-induced antibody secretion is IL-4 dependent.

Suppression by IL-2 of IgE production by B cells stimulated by IL-4.

IgE production was obtained from B cells of BALB/c or nude mice when these cells were cultured with IL-4 plus LPS. IL-2 added to these cultures at the start (day 0), 1 or 2 days later completely suppressed the production of IgE. The production of IgG1 was also inhibited, but only if IL-2 was added on day 0. The production of other isotypes (IgM, IgG2a, IgG2b) was only slightly decreased by addition of IL-2. No suppression of IgE or IgG1 production was observed if monoclonal anti-IL-2 was added, whereas anti-IFN-gamma had no effect on the suppression of the production of these isotypes. The expression of CD23 on the third day of culture on B cells stimulated with LPS and IL-4 was markedly decreased when IL-2 was added to the cultures on day 0. Addition of monoclonal anti-IL-2 suppressed all effects produced by IL-2, whereas addition of anti-IFN-gamma had no effect. These results show that the suppression by IL-2, at least for the first signaling processes, are different from the suppression produced by IFN-gamma.

The action of interleukin-4 on antigen-specific IgG1 and IgE production by interaction of in vivo primed B cells and carrier-specific cloned Th2 cells.

The production of anti-trinitrophenyl (TNP) antibodies of different isotypes from in vivo primed B cells was studied using the plaque-forming cell method. It was shown that these B cells secrete anti-trinitrophenyl antibodies of different isotypes only in the presence of Th2 cells specific for keyhole limpet hemocyanin (KLH) and the hapten-carrier conjugate TNP-KLH. Lipopolysaccharide-stimulated primed B cells without cells from the Th2 clone did not produce anti-TNP-specific IgG1 or IgE antibodies even in the presence of the hapten-carrier antigen TNP-KLH. Supernatants from these Th2 clones cultured with antigen-presenting cells and the complete antigen were unable to activate primed B cells for antibody secretion. Cognate interaction between primed B cells and carrier-specific Th2 cells is a prerequisite for hapten-specific IgG1 or IgE production. Anti-IL-4 antibody inhibited secretion of anti-hapten IgE antibody. Therefore, for production of anti-hapten antibody of the IgE isotype IL-4 is also necessary.

Protective immunity and eosinophilia in IgE-deficient SJA/9 mice infected with Nippostrongylus brasiliensis and Trichinella spiralis.

To elucidate the roles of IgE antibody in host responses to helminth infection, selective IgE-deficient SJA/9 mice were infected with the nematode parasites Nippostrongylus brasiliensis, which elicits remarkable potentiated IgE production, and Trichinella spiralis, which induces strong anti-Trichinella IgE antibody production in normal mice. The kinetics of blood eosinophilia, worm burden after primary infection, and resistance to secondary infection in SJA/9 mice were the same in both infections as those in congenic SJL/J mice used as an IgE-producing control. These results indicate that the host responses examined here operate under IgE-independent mechanisms.

Heteroclitic antibodies: differences in fine specificities between monoclonal antibodies directed against dinitrophenyl and trinitrophenyl haptens.

The inhibition of binding of monoclonal antibodies by different haptens was studied using the 50% antibody binding assay. The binding of antidinitrophenyl and antitrinitrophenyl antibodies to dinitrophenylated or trinitrophenylated bovine serum albumin could be inhibited by monovalent dinitrophenyl or trinitrophenyl epsilon-aminocaproic acid. Some of the antibodies could be inhibited to a greater degree with the cross-reacting haptens than with the haptens homologous to the immunizing antigen, therefore these antibodies were heteroclitic.

A novel method to investigate the heterocliticity of antibodies.

Monoclonal and anti-dinitrophenyl and anti-trinitrophenyl IgE antibodies were used to measure heterocliticity using competitive inhibition assays with homologous and heterologous haptens. The antibodies or antibody-containing ascites fluids were diluted to give 50% of the maximum binding to wells of antigen-coated microtiter plates. The % inhibition of binding of the antibody to the antigen by various concentrations of homologous and heterologous haptens at a standard dilution of antibody can then be compared. The advantages of this method of determination of heterocliticity are that it is fast, simple, quantitative and does not need radiolabeled reagents.