Search

High titer and persistent antihapten IgE production in SJL mice can be obtained using appropriate immunization and radiation. Nonirradiated mice rapidly terminate this antihapten IgE production. Radiation was not necessary to prolong antihapten IgE production in other strains of mice. Termination can be obtained even in irradiated SJL mice by transferring normal SJL spleen cells. That the suppressor cells are T cells is shown by using thymocytes or cells treated with anti-Thy 1.2 and complement. No appreciable suppressive effect by normal spleen cells could be demonstrated on IgG1 production in SJL mice. The characteristic of low and transient IgE antibody response in SJL mice is inherited as a recessive trait controlled by a single Mendelian autosomal gene and is not linked to the H-2-gene complex. This characteristic does not depend on the infectivity of Nippostrongylus brasiliensis, the effect of anticarrier antibody, or the recognition of antigen.

Groups of guinea pigs were maintained with alcohol solutions not sufficient to result in liver dysfunction prior to and during investigations designed to determine whether ethanol would nonetheless impair cell-mediated or humoral immunity. No impairment of either was observed in any of the experimental groups.

To investigate why SJA9 mice do not produce IgE antibody, we took advantage of the adoptive transfer method and the carrier effect. Antibody-producing B cells (donor I) were primed with 2,4-dinitrophenylated ovalbumin (DNP-OVA) and carrier-specific T cells (donor II) were primed with keyhole limpet hemocyanin (KLH). The recipients were challenged with DNP-KLH. When 0.2 micrograms of DNP-OVA was used and the donor II cells were from SJL mice the recipient produced anti-DNP IgE. When donor I cells were from the SJL strain and donor II cells were from the SJA9 strain the recipient produced anti-DNP IgE. This pointed to a T-cell defect (absent or functionally inactive T epsilon o cell) in the SJA9 strain, which could be corrected either by injecting unprimed T cells from the SJL strain into the SJA9 donor I or by infection with Nippostrongylus brasiliensis, a hookworm, after priming. It seems that in the SJA9 strain in the absence of functioning T epsilon o cells isotype-specific (IgE) suppression, described previously in the SJL strain, is more pronounced, because when the SJA9 donor I was primed with 1 microgram of DNP-OVA only trace amounts of anti-DNP IgE were produced with SJL donor II cells.

The mechanism of selective anti-hapten IgE antibody production was studied in SJL mice. Using an adoptive transfer method of spleen cells into syngeneic recipients irradiated with a sublethal dose of 600 rads, it was demonstrated that for the suppression of anti-dinitrophenyl (DNP) IgE antibody production the interaction of two subsets of T cells is necessary. DNP-primed B cells and carrier-primed T helper cells are taken from donors primed with small amounts of DNP-carrier conjugates. Without injection of other cells, high titer and persistent anti-DNP antibodies are produced in the recipients. The two subsets of T cells that are active in suppression of IgE are taken from two types of donors: one donor is immunized (hyperprimed) with larger amounts of carrier protein twice, the other is an unprimed donor. The carrier for hyperpriming the first type of donor may be unrelated to the carrier used for priming the helper T cells. To bring about anti-DNP IgE suppression it is necessary that the animals should be challenged with the same DNP-carrier conjugate used for priming the B and T helper cells. If the hyperprimed donors were immunized with a heterologous, unrelated carrier, then this heterologous unconjugated carrier must also be injected together with the homologous DNP-carrier conjugate. In these conditions, anti-DNP IgE antibody production is suppressed, but the production of anti-DNP IgG1 antibody is not diminished.

SJL mice were immunized with 1 microng dinitrophenylated keyhole limpet hemocyanin in 1 mg Al(OH)3. The mice were infected 21 days later with 750 third stage larvae of Nippostrongylus brasiliensis. On day 35, 14 days after infection, they were injected with 1 microng DNP-N, brasiliensis extract (Nb) in 1 mg Al(OH)3. In order to obtain high titer and persistent anti-DNP IgE antibody the mice were irradiated (540 R) 1 day after injection of DNP-Nb. Suppression of anti-DNP IgE antibody production was induced by spleen cells from normal SJL mice. Suppression of IgE antibody response is also obtained by an extract from normal SJL spleen cells. The suppressor substance from normal SJL spleen cell extract is a heat-labile protein, and is not absorbed by anti-mouse immunoglobulin. The mol wt of this substance is larger than 300,000 daltons as determined by gel filtration on Sephadex G-200, but after ultracentifugation, the supernate still has suppressive activity on IgE antibody production.

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 IgG1against 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 IgG1production 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 IgG1production 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-2,4-dinitrophenyl (DNP) IgE producing hybridoma B 53 when injected subcutaneously is established equally well in syngeneic BALB/c (heavy-chain allotype a) and congenic CB20 (heavy-chain allotype b) mice. However, secretion of anti-DNP IgE monoclonal antibody is greatly suppressed in CB20 mice. B 53 cells taken from the subcutaneous tumors of CB20 mice produce anti-DNP IgE in vivo in BALB/c mice and in vitro. No difference was observed in IgE production between these cells and the controls taken from BALB/c mice. The suppression of IgE production was due to T cells and/or their product(s) of CB20 mice.

Guinea pigs hyperimmunized with E. colibacteria emulsified in complete Freund's adjuvant produced large amounts of 7SΓ2globulins. However, animals immunized by this method, as well as others initially immunized with bacteria administered intraperitoneally or intravenously, failed, with one exception, to produce 7SΓ1guinea pig skin sensitizing anti-E. coliantibodies.

Passive immune lysis of antigen-coated erythrocytes provoked in vitro by guinea pig γ2 antihapten antibodies in the presence of complement, is inhibited by guinea pig γ1 antibodies directed against the same specificity. This inhibition of the lytic effect of complement-fixing γ2 antibodies is presumably due to the competition for antigen by non-lytic γ1 antibodies.

Additional evidence has been obtained to show that different guinea pig anti-hapten antibodies differ in the structure of their L polypeptide chains. Antibodies from animals immunized with the same hapten conjugated to different carrier proteins gave similar starch gel electrophoretic patterns after dissociation of their chains. In a study of fine differences of specificity, cross-reacting antibodies were found to have some L chains with the same electrophoretic mobility. The multiplicity of L chain bands found in the characteristic starch gel electrophoretic patterns of dissociated anti-DNP antibodies was shown to be a reflection of the heterogeneity of antibodies of slightly different specificities. Reduction and alkylation of the active fragment produced by digestion of antibodies with papain yielded starch gel electrophoretic bands corresponding in mobility to L chains. The results are consistent with the notion that L chains are involved in the acquisition of immunologic specificity.