Induction of anti-viral immune response by immunization with monoclonal anti-idiotype antibodies directed to private idiotopes

Fetal and Neonatal Illnesses Caused or Influenced by Maternal Transplacental IgG and/or Therapeutic Antibodies Applied During Pregnancy

The human fetus is protected by the mother’s antibodies. At the end of the pregnancy, the concentration of maternal antibodies is higher in the cord blood, than in the maternal circulation. Simultaneously, the immune system of the fetus begins to work and from the second trimester, fetal IgM is produced by the fetal immune system specific to microorganisms and antigens passing the maternal-fetal barrier. The same time the fetal immune system has to cope and develop tolerance and T_REG cells to the maternal microchimeric cells, latent virus-carrier maternal cells and microorganisms transported through the maternal-fetal barrier.

The maternal phenotypic inheritance may hide risks for the newborn, too. Antibody mediated enhancement results in dengue shock syndrome in the first 8 month of age of the baby.

A series of pathologic maternal antibodies may elicit neonatal illnesses upon birth usually recovering during the first months of the life of the offspring. Certain antibodies, however, may impair the fetal or neonatal tissues or organs resulting prolonged recovery or initiating prolonged pathological processes of the children.

The importance of maternal anti-idiotypic antibodies are believed to prime the fetal immune system with epitopes of etiologic agents infected the mother during her whole life before pregnancy and delivery.

The chemotherapeutical and biological substances used for the therapy of the mother will be transcytosed into the fetal body during the last two trimesters of pregnancy. The long series of the therapeutic monoclonal antibodies and conjugates has not been tested systematically yet. The available data are summarised in this chapter.

The innate immunity plays an important role in fetal defence. The concentration of interferon is relative high in the placenta. This is probably one reason, why the therapeutic interferon treatment of the mother does not impair the fetal development.

Allergen IgE-isotype-specific suppression by maternally derived monoclonal anti-IgG-idiotype

BACKGROUND

The dramatic increase of IgE-mediated allergic diseases in western countries demonstrates the urgent need for new therapeutic or prophylactic approaches. In mice, a prophylactic long-lasting allergen-specific suppression of IgE responsiveness is induced by maternal IgG antibodies to allergens like ovalbumin, phospholipase A(2) (bvPLA(2)) or ovomucoid. As neonatal application or maternally derived pathogen-reactive antibodies (idiotypes) as well as corresponding anti-idiotypes can induce anti-microbial protection, we probed the transgenerational IgE-suppressive mechanism with a syngeneic monoclonal anti-idiotypic antibody.

METHODS

The monoclonal bee-venom-phospholipase A(2) (bvPLA(2))-reactive IgG antibody MS613 (idiotype) or the corresponding syngeneic anti-idiotype II/2-19 were injected during the first 2 days postpartum to the dams. Immunization of offspring with minute doses of IgE-inducing bvPLA(2) was started at an adult age of 3(1/2) months.

RESULTS

The postnatal transfer of the anti-bvPLA(2) idiotype MS613 or the corresponding anti-idiotype II/2-19 induced long-lasting allergen-specific IgE suppression in a dose-dependent manner, while the IgG response to the allergen developed normally. Quantitatively, the anti-idiotype was more effective than idiotype. Molecular modeling of the idiotype-anti-idiotype complex and its comparison with the bvPLA(2) structure revealed that the anti-idiotype does not mimic bvPLA(2) epitopes and thus can not be regarded as an internal image antibody and, consequently, does not function as a surrogate antigen.

CONCLUSIONS

Idiotypic network reactivity is at least one major factor for induction of transgenerational IgE suppression by maternal IgG antibodies. If applicable to humans, these data suggest the possibility of a prophylactic and possibly therapeutic treatment of IgE-mediated allergic diseases with anti-idiotypic antibodies.

Generalization of single immunological experiences by idiotypically mediated clonal connections

Clonal interactions of B cells by idiotope-specific mutual recognition of their antigen receptors with the participation of T cells were assumed to form a web of unknown density, referred to as the idiotypic network. Although these clonal connections were proposed to fulfill important internal regulatory functions, their biological significance, especially in relation to antigen-induced immune responses, remained a mystery. In view of this, we postulate that the basic function of the idiotypic internal connection between B and T cell antigen receptors is to transform antigen-induced cellular activations, by idiotypic crossreactivity, into the regulation of cell clones with different antigen specificities. This process leads not only to the suppression of major clones but also to the activation of minor ones. The latter activating property may allow the generalization of single antigenic experiences, so that the immune system in its entirety benefits in its battle against environmental microbes. Such idiotypic clonal interactions are particularly effective in early ontogeny. During a short neonatal imprinting period, maternal immunological knowledge in the form of somatically mutated, high-affinity IgG antibodies, acquired through a continuous encounter with external antigens, guides the initial ontogenetic development of the immune system and so exerts long-lasting transgenerational advantageous effects in the offspring.

Immunoglobulin-like domain of HIV-1 envelope glycoprotein gp120 encodes putative internal image of some common human proteins

By examining sequence similarity between the V3-loop of gp120 from various HIV-1 isolates and human proteins, we found that the V3 loop portion KKGIAIGPGR in strain New York 5 (HIV-1NY5) shares 70% identical residues with the collagen-like region (CLR) of human complement component C1q-A. C1q CLR was found to react with autoantibodies from several autoimmune disorders. Thus, we assumed that it would be of interest to find out the C1q reactivity with antibodies from AIDS sera. The results obtained show that the V3 loop-derived synthetic peptide KKGIAIGPGRTLY reacts both with AIDS patients sera and with antibodies purified on the V3 loop peptide-affinity column. The same affinity-purified antibodies bind also to C1q molecules. Since, according to our previous results, HIV-1 V3 loops and immunoglobulin heavy chain variable regions (Ig VH) share several common features, we suggest that the envelope of HIV-1NY5 bears a functional internal image of the C1q-A CLR epitope. Therefore, gp120 could manipulate the immune network and contribute to HIV-induced autoimmunity.

A highly selected panel of anti-CD4 antibodies fails to induce anti-idiotypic antisera mediating human immunodeficiency virus neutralization

Anti-CD4 antibodies directed to the N terminus of CD4 can inhibit human immunodeficiency virus (HIV) infection. Therefore, it has been proposed that some of these reagents may contain idiotypic determinants which conformationally model the binding site expressed on gp120. In this report, we have selected a panel of anti-CD4 monoclonal antibodies as idiotypic mimics of gp120 by employing cross-blocking techniques, and CD4 epitope mapping using site-directed mutagenesis. These studies suggest that only 4 out of the original panel of 12 would be expected to represent suitable candidates for modelling the gp120 binding site. Nevertheless, anti-idiotypic antisera raised against these antibodies failed to inhibit gp120 binding to CD4. This negative result may reflect the incomplete modelling of the virus binding site by anti-CD4, or the lack of internal image antibody in the anti-idiotypic preparations. Alternatively, the binding site on gp120 may not be accessible to antibody neutralization, excluding the possibility of an idiotypic vaccine to HIV based on anti-CD4 antibody as surrogate antigen.

Induction of immune response to bovine herpesvirus-1 with anti-idiotypic antibodies

Previously, we prepared rabbit anti-idiotypic (anti-Id) antibodies against murine monoclonal antibodies (MAbs) specific for the major bovine herpesvirus-1 (BHV-1) envelope glycoproteins. Glycoprotein III (gIII) contains neutralization epitopes and may be the virus attachment protein. Anti-Id antibodies to a neutralizing MAb that reacts with gIII were purified by sequential immunoaffinity chromatography. Immune responses to the purified anti-Id reagent and BHV-1 were compared in mice. Both groups of mice produced BHV-1-specific neutralizing antibodies. However, lymphocyte proliferative responses and interferon and interleukin-2 production were specific for the respective immunizing antigens. These results suggest that the anti-Id reagent may bear an internal image of a B-cell-stimulating epitope of glycoprotein gIII; however, this epitope does not stimulate a virus-specific cellular immune response in mice.