Idiotypic networks and their possible exploitation for manipulation of the immune response

Clinical significance of measuring levels of tumor necrosis factor-alpha and soluble interleukin-2 receptor in nasopharyngeal carcinoma

CONCLUSION

Changes in tumor necrosis factor-alpha (TNF-alpha) and soluble interleukin-2 (sIL-2R) levels appear to be closely related to tumor progression and prognosis in nasopharyngeal carcinoma (NPC). Further investigation is suggested.

OBJECTIVES

The study examined whether changes in TNF-alpha and sIL-2R in NPC can be used to predict tumor progression and prognosis.

PATIENTS AND METHODS

The study was carried out in 58 patients with NPC newly diagnosed from December 2003 to December 2006 at a single institution and 60 control subjects of comparable age. Blood levels of TNF-alpha and sIL-2R were monitored before, during, and 3 months and 1 year after treatment.

RESULTS

Differences in TNF-alpha level between patients with NPC in all four stages and healthy controls and in sIL-2R level between patients with advanced stage NPC and healthy controls were significant (p <0.05). Furthermore, 1 year after completing radiotherapy, levels of TNF-alpha and sIL-2R in patients with recurrent tumors were significantly different from those in patients without recurrence and healthy control subjects.

The evolution of mathematical immunology

The types of mathematical models used in immunology and their scope have changed drastically in the past 10 years. Classical models were based on ordinary differential equations (ODEs), difference equations, and cellular automata. These models focused on the 'simple' dynamics obtained between a small number of reagent types (e.g. one type of receptor and one type of antigen or two T-cell populations). With the advent of high-throughput methods, genomic data, and unlimited computing power, immunological modeling shifted toward the informatics side. Many current applications of mathematical models in immunology are now focused around the concepts of high-throughput measurements and system immunology (immunomics), as well as the bioinformatics analysis of molecular immunology. The types of models have shifted from mainly ODEs of simple systems to the extensive use of Monte Carlo simulations. The transition to a more molecular and more computer-based attitude is similar to the one occurring over all the fields of complex systems analysis. An interesting additional aspect in theoretical immunology is the transition from an extreme focus on the adaptive immune system (that was considered more interesting from a theoretical point of view) to a more balanced focus taking into account the innate immune system also. We here review the origin and evolution of mathematical modeling in immunology and the contribution of such models to many important immunological concepts.

Dissection of an antibody paratope into peptides discloses the idiotope recognized by the cognate anti-idiotypic antibody

Using methods of parallel synthesis, the complete amino acid sequence of an Ab 1 antibody (Tg 10, an anti-human thyroglobulin monoclonal antibody) was made in the form of a set of 100 synthetic overlapping peptides. This set of immobilized peptides was allowed to react with the cognate Ab2 (AI 10, a highly purified rabbit anti-idiotypic polyclonal antibody to Tg 10). A dominant peptide idiotope, INTFSGVPTYA, was thus mapped, which corresponds mainly to the CDR2 region from the V(H) domain of the Tg 10 mAb. A synthetic peptide replica of this idiotope was found to bind to AI 10 with an affinity (K(D) in the 10(-8) M range, as measured using BIACORE technology) which represents a significant part of the affinity of the complete Tg 10 antibody (K(D) in the 10(-9) M range). The synthetic peptide also elicited anti-idiotypic antibodies in rabbits that recognized specifically the Ab1 antibody in an Ab1- and antigen-inhibitable manner. The peptide idiotope was further characterized chemically by the identification of residues important for binding to the Ab2 and by modelization of its structure. Our approach makes it readily possible to map and characterize functional, continuous-type idiotopes that could be further used to manipulate the immune response by peptide technologies.

Epitope-specific focusing of the immune response to a minimized human chorionic gonadotropin analog

Minimized proteins have long been used to elicit an immune response to particular regions of a protein antigen. Most efforts to derive minimized proteins have employed synthetic peptide fragments. This approach works well for linear epitopes but poorly for conformational epitopes. Here we describe a homodimeric human chorionic gonadotropin (hCG) analog that retains the conformation of related parts of hCG and elicits high affinity specific antibodies. This novel immunogen displays the tertiary structure of selected loops of the protein but lacks structures that could elicit potentially undesirable antibodies.

Colorectal cancer vaccines

BACKGROUND

Advances in molecular pathology have enabled a number of colorectal cancer antigens to be identified and characterized. The commonest investigated include 17-1A, 791Tgp72 and carcinoembryonic antigen. Vaccines have been developed that stimulate the immune system to target these antigens. This paper reviews current areas of research in this field.

METHODS AND RESULTS

Relevant articles were obtained on vaccines for colorectal cancer from Medline and the Bath Information Data System. A number of approaches are currently being evaluated in Phase I, II and III trials. These include anti-idiotypic antibody immunization, DNA vaccines, mucin and heat shock protein-based vaccines, oncogenes and viral vectors.

CONCLUSION

Evidence is accumulating to suggest that immune responses may be generated against colorectal cancer using these approaches. While the concept of vaccination against this malignancy is essentially experimental, surgeons should be aware of current advances.

Characterization of anti-anti-idiotypic antibodies that bind antigen and an anti-idiotype

Two mouse monoclonal anti-anti-idiotopic antibodies (anti-anti-Id, Ab3), AF14 and AF52, were prepared by immunizing BALB/c mice with rabbit polyclonal anti-idiotypic antibodies (anti-Id, Ab2) raised against antibody D1.3 (Ab1) specific for the antigen hen egg lysozyme. AF14 and AF52 react with an "internal image" monoclonal mouse anti-Id antibody E5.2 (Ab2), previously raised against D1.3, with affinity constants (1.0 x 10(9) M-1 and 2.4 x 10(7) M-1, respectively) usually observed in secondary responses against protein antigens. They also react with the antigen but with lower affinity (1.8 x 10(6) M-1 and 3.8 x 10(6) M-1). This pattern of affinities for the anti-Id and for the antigen also was displayed by the sera of the immunized mice. The amino acid sequences of AF14 and AF52 are very close to that of D1.3. In particular, the amino acid side chains that contribute to contacts with both antigen and anti-Id are largely conserved in AF14 and AF52 compared with D1.3. Therapeutic immunizations against different pathogenic antigens using anti-Id antibodies have been proposed. Our experiments show that a response to an anti-Id immunogen elicits anti-anti-Id antibodies that are optimized for binding the anti-Id antibodies rather than the antigen.

Anti-idiotypic antibodies as surrogate antigens for vaccinating against the cattle tick, Boophilus microplus

QU13, a monoclonal antibody (mAb) raised against midgut (GM) antigens from Boophilus microplus and shown to recognise antigens which protect cattle from tick challenge was used to immunise cattle and rabbits to produce anti-idiotypic antibodies (AIA). Polyclonal antisera against mAb QU13 were produced in rabbits and cattle. AIA were purified from these antisera by affinity chromatography procedures. These purified AIA were found to block mAb QU13 binding to GM in enzyme-linked immunosorbent assay (ELISA). AIA purified from bovine antiserum elicited an immune response in cattle to antigens extracted by detergent from the midgut of B. microplus (TXGM) after the fourth vaccination (P = 0.06) compared with the bovine immunoglobulin (Ig) control. The mean antibody level in the group of experimental cattle vaccinated with AIA purified from rabbit antisera was significantly higher (P < 0.03) than that of bovine Ig control cattle after the fourth vaccination and an anamnestic response (P < 0.11) occurred in the rabbit AIA vaccinated group of cattle when a single booster dose of 300 micrograms of TXGM was given after the first tick challenge. The positive control group of cattle vaccinated with TXGM were significantly protected (P < 0.05) against tick infestation after the booster dose of 300 micrograms of TXGM. The AIA vaccinated groups of cattle were not protected against challenge with 20,000 larval ticks either before or after the booster injection of 300 micrograms of TXGM.

An anti-idiotype antibody which mimics the inner-core region of lipopolysaccharide protects mice against a lethal challenge with endotoxin

Recently, we described the generation and characterization of an Armenian hamster Ab2 beta anti-idiotype monoclonal antibody (MAb4G2) specific for the binding site of a mouse monoclonal antibody, MAbY1-4A6, directed against the conserved 2-keto-3-deoxyoctulosonate (Kdo)-containing inner-core region of lipopolysaccharide (LPS) (S. K. Field, M. Pollack, and D. C. Morrison, Microb. Pathog. 15:103-120, 1993). In that study, mice and hamster immunized with MAb4G2 generated serum immunoglobulin G and M (IgG and IgM) antibodies which cross-react with Salmonella minnesota R595-chemotype rough mutant LPS (Re-LPS). In this report, we demonstrate that in C3Heb/FeJ mice, MAb4G2 elicits an immune response which is characterized by specific binding of antibody to Re-LPS, as assessed by enzyme-linked immunosorbent assay. The practical use of MAb4G2 as a potentially effective therapeutic agent against gram-negative bacterial sepsis is suggested by the demonstration that immunization of these mice with MAb4G2 results in significant protection of D-galactosamine-sensitized animals against an otherwise lethal dose of Re-LPS. Assessment of the temporal changes in Re-LPS-specific serum antibody titers from mice immunized with MAb4G2 or Re-LPS over a 40-day period indicates that immunization with Re-LPS elicits significantly higher titers of serum IgM antibodies compared with those in animals immunized with MAb4G2. Conversely, two immunizations with MAb4G2 result in an up to 10-fold increase in anti-Re-LPS-specific IgG serum antibody titers relative to those obtained in mice immunized with Re-LPS. Nineteen days after the secondary boost with MAb4G2, anti-Re-LPS-specific IgG serum antibody titers were significantly higher (three- to fourfold) compared with those in Re-LPS-treated animals. Initial immunization with the anti-idiotype antibody primes animals for enhanced secondary responses to Re-LPS, as assessed by the titers of anti-Re-LPS-specific IgG profiles. These data suggest the potential utility of MAb4G2 as a candidate vaccine against the lethal properties of gram-negative bacterial LPS.

Antibody synthesis induced by endogenous internal images

In this study, immunization with a vaccine consisting of multiple F(ab')2 fragments of affinity-purified antitetanus toxoid antibodies covalently bound to a carrier protein successfully induced antitetanus toxoid antibodies. Further studies showed that this vaccine preparation contained no biologically detectable tetanus antigen. The induced antitetanus antibody (Ab1') titer was higher than the titer of antibodies binding control antigens. The immunizing F(ab')2 preparation did not elicit a secondary antitetanus response from mice primed with tetanus toxoid and, hence, appeared free of tetanus epitopes. The specificity of Ab1' was established by absorption and inhibition with antigen. Immunization with antitetanus F(ab')2 (Ab1') fragments appears to have elicited naturally occurring autologous antitetanus toxoid antibody (Ab1') through an idiotypic pathway. As predicted by network theory, anti-idiotype (Ab2) and antitetanus (Ab1') cycled reciprocally. Clonotypic characterization of Ab1' using isoelectric focusing and affinity immunoblotting showed increases in Ab1' titer to be the result of increased synthesis by limited subsets of antitetanus toxoid B-cell clones and not increased synthesis by multiple clones, as is characteristic of antigen-driven Ab1 responses. Many Ab1 and Ab1' clonotypes had identical pIs, suggesting that they either share V region genes or are the product of the same B-cell clones. These findings indicate that immunization with polyclonal multivalent Ab1 preparations can trigger active synthesis of antibodies with the same specificity. The results provide further evidence for naturally occurring idiotypic cascades that could be exploited for studies of catalytic antibodies.

New approaches for the development and application of monoclonal antibodies for the diagnosis and therapy of human cancer

Monoclonal antibodies (MAbs) represent potentially important reagents for both the diagnosis and therapy of human cancer. Innovative approaches are resulting in the improved production of MAbs and an enhanced ability to use these molecules therapeutically. Application of genetic engineering to MAb development is also resulting in the production of MAbs displaying enhanced target specificity. Of particular value for cancer therapy will be catalytic, bispecific, anti-idiotypic and human MAbs. By using agents that can augment the expression of tumor-associated antigens on cancer cells, a further increase in the utility of MAbs in cancer therapy will be forthcoming.

Biological response modifiers and infectious diseases: actual and potential therapeutic agents

Biological response modifiers (BRMs) are agents which can modify the immune response to cancer or invasion of the organism by infectious agents. An explosive appearance of new BRMs has resulted from the development of recombinant gene technology and the availability of monoclonal antibodies. Colony-stimulating factors first became available for the prevention of neutropenia but may also have a role in the treatment of infections. Interleukin-1 is being tested as a modular of hematopoiesis and may be useful as a helper factor for T- and B-cell function. Immunoglobulins are being used against viral and bacterial infections while interferons can prevent viral upper respiratory infections and suppress or irradicate some viral hepatitides. Other BRMs which show promise include chemical agents and traditional herbal medicines.

Effectiveness of high-dose intravenous immunoglobulin in a case of acquired von Willebrand syndrome with chronic melena not responsive to desmopressin and factor VIII concentrate

A patient with benign monoclonal IgG lambda paraproteinemia, acquired von Willebrand syndrome (AVWS), and chronic melena successfully responding to high-dose intravenous immunoglobulin (lvlg) is reported. Coagulation parameters at admission were APTT (ratio) 1.68; VIII:C 11 IU/dL; vWF:Ag 7 IU/dL:Ricof less than 3 IU/dl. RIPA was greater than 1.8 mg/ml, and bleeding time (BT) was prolonged (18 min). No evidence for an in vitro inhibitor against the VIII/vWF complex was observed. VIII/vWF measurements showed a short-lived increase after both DDAVP and Hemate P, and BT was transiently normalized. After intravenous Ig (1 g/kg for 2 days), VIII/vWF measurements, hemostatic parameters and multimeric pattern were completely corrected (VIII/C 106 IU/dl, vWF:Ag 168 IU/dl, RiCof 147 IU/dl, APTT ratio 0.89, BT 5'), with a return to pre-infusion values after 15 days. Hemoccult test became negative and packed red cell transfusions, of which 130 units were administered during the last year, were no longer required. After 18 months the patient is on maintenance treatment with repeated courses of Ig, at 3 to 4-week intervals based on VIII/vWF and BT monitoring.

Immunization strategies for the production of rat monoclonal anti-idiotope antibodies

Anti-idiotypic antibodies are powerful reagents for the study of immunoregulation, and have potential interest as vaccines against tumors and infectious diseases. Three immunization strategies for the production of rat monoclonal anti-idiotope antibodies have been compared in this paper. Male Wistar rats were immunized i.p. and at multiple subcutaneous sites with 750 micrograms of purified monoclonal antibody against Plasmodium falciparum for three times and subsequently boosted by (1) intraperitoneal injection with 750 micrograms of the immunogen, (2) intravenous inoculation with 400 micrograms of the IgG, and (3) intrasplenic immunization with 200 micrograms of the idiotype. With the intraperitoneal boost method, the frequency of hybrids with anti-idiotope activity was 0.3-0.9% with 62.8-85.2% of the seeded wells containing hybrids. In the intravenous boost group, the percentage of hybrids demonstrating anti-idiotope activity increased to 11.0-13.3% with 80.2-97.9% of the hybrid efficiency. When immunized by the intrasplenic boost route, the frequency of anti-idiotope hybrids generated rose to 12.9-16.4% with 82.3-96.6% of the hybrid efficiency. There was no obvious effect of the boost immunizing methods on the generation of rat monoclonal anti-mouse IgG antibodies. These results indicated that the multiple-site immunization followed by intravenous or intrasplenic boost injection was an appropriate immunizing method for the production of monoclonal anti-idiotope antibodies.

The servant idiotype network

Network Antigens are idiotopic markers which are expressed on antibodies of a given specificity. These Network Antigen Idiotopes are part of specific immune responses and are selected through the process of antigen-driven maturation. Their natural role in immunity is the regulation of the response via idiotypic network interaction. The biological power of Network Antigens can be harnessed by generating monoclonal Ab2s against polyclonal disease-derived and specific Ab1. Because network antigens play an important biological role in immunity, it becomes difficult to call the Idiotype Network selfish. We believe that the organization and selection of a small antibody repertoire, which is needed to maintain a disease free existence, is accomplished by the idiotypic network. Furthermore, if we better understand the blueprint of this network we can begin to take advantage of the primed state of clones in the network to intervene, either to stimulate beneficial responses, or to suppress harmful immunities using antibodies which recognize the key organizer and controllers in the network.

Three-dimensional structure of an idiotope-anti-idiotope complex

Serologically detected antigenic determinants unique to an antibody or group of antibodies are called idiotopes. The sum of idiotopes of an antibody constitute its idiotype. Idiotypes have been intensively studied following a hypothesis for the self-regulation of the immune system through a network of idiotype-anti-idiotype interactions. Furthermore, as antigen and anti-idiotypes can competitively bind to idiotype-positive, antigen-specific antibodies, anti-idiotypes may carry an 'internal image' of the external antigen. Here we describe the structure of the complex between the monoclonal anti-lysozyme FabD1.3 and the anti-idiotopic FabE225 at 2.5 A resolution. This complex defines a private idiotope consisting of 13 amino-acid residues, mainly from the complementarity-determining regions of D1.3. Seven of these residues make contacts with the antigen, indicating a significant overlap between idiotope and antigen-combining site. Idiotopic mimicry of the external antigen is not achieved at the molecular level in this example.

The thymus-dependent nature of the murine antibody response to a monoclonal anti-idiotypic antibody to the Neisseria meningitidis serogroup C capsular polysaccharide

Idiotype vaccines are proteins which may offer an alternative strategy for the conversion of a thymus-independent antigen into a thymus-dependent immunogen. To examine this question, we have studied the nature of the immune response to a monoclonal anti-idiotypic antibody, designated 6F9, which acts as a surrogate of Neisseria meningitidis serogroup C capsular polysaccharide, and compared this response to the nominal antigen, the meningococcal C-polysaccharide (MCP). BALB/c mice immunized with an optimal dose (100 micrograms) of 6F9 generate a specific anti-MCP IgG response which is maximal after 4 weeks. Secondary immunization with 6F9 results in a three- to five-fold increase in the specific IgG response. Mice given an optimal immunizing dose of MCP (5 micrograms) failed to generate an anti-MCP IgG response. No secondary response is detectable in mice immunized with MCP. Animals immunized with 6F9 and subsequently challenged with live meningococci group C show a significant anti-MCP IgG response. BALB/c nu/nu mice fail to generate an anti-MCP IgG antibody response to 6F9, while the nu/+ controls generate an anti-MCP IgG antibody titer 100 times that of the MCP-immunized mice. Neonatal mice that failed to respond to MCP developed early IgM and a subsequent IgG anti-MCP response after immunization with 6F9. These data demonstrate that the anti-idiotype 6F9, the combining site of which contains a surrogate image of the meningococcal group C capsular polysaccharide, evokes the responses expected of a T-dependent antigen.

Genetic engineering of plants for virus resistance

Historically, control of plant virus disease has involved numerous strategies which have often been combined to provide effective durable resistance in the field. In recent years, the dramatic advances obtained in plant molecular virology have enhanced our understanding of viral genome organizations and gene functions. Moreover, genetic engineering of plants for virus resistance has recently provided promising additional strategies for control of virus disease. At present, the most promising of these has been the expression of coat-protein coding sequences in plants transformed with a coat protein gene. Other potential methods include the expression of anti-sense viral transcripts in transgenic plants, the application of artificial anti-sense mediated gene regulation to viral systems, and the expression of viral satellite RNAs, RNAs with endoribonuclease activity, antiviral antibody genes, or human interferon genes in plants.

Regulation of retinal autoimmunity via the idiotypic network

The immune response to self antigens is regulated through an interplay of idiotypes and anti-idiotypes expressed on antibodies and lymphoid cells. The equilibrium of the different components of the immune system has been modulated in various autoimmune diseases by manipulation of the idiotypic network. Experimental autoimmune uveoretinitis (EAU) was induced in rats with one foot pad injection of S-antigen (S-Ag) in complete Freund's adjuvant (CFA). 1. Injection of rats with the mouse anti-S-Ag monoclonal antibody (mAb) S2D2 either simultaneously with or before S-Ag challenge, led to an anti-idiotypic (anti-Id) response and to inhibition of EAU. 2. Suppression of the disease could be passively transferred using lymph node and/or spleen cells from donors immunized with S2D2 to naive recipients, prior to immunization with bovine S-Ag in CFA. In contrast, one injection of IgG from S2D2-immunized rats did not prevent EAU. 3. Preimmunization against a purified rat polyclonal anti-Id-S2D2 antibody (internal image of the epitope recognized by mAb S2D2) before S-Ag challenge also allowed to inhibit EAU. As S2D2 was the best of several anti-S-Ag mAbs tested for disease inhibition, the epitope recognized by S2D2 should be of particular interest in the regulation of the immune response. This epitope has been localized to the N-terminal region of S-Ag, in the amino acid sequence 40-50. The S2D2 epitope is distant from all presently known uveitogenic sites. Manipulation of the idiotypic network for selected epitopes of the autoantigen may provide a valuable approach to therapy of autoimmune disease.

Experimental autoimmune uveoretinitis: idiotypic regulation and disease suppression

Experimental autoimmune uveoretinitis (EAU), a mostly T-cell dependent disease, was induced in laboratory animals by a single immunization with retinal extract or purified S-antigen in complete Freund's adjuvant. It can be prevented or suppressed by injections of either the autoantigen or monoclonal antibodies against the autoantigen. The suppression of EAU by these antibodies was associated with an anti-idiotypic antibody response. The inhibition of the pathogenic immune response by the antigen or the antibodies could be explained, according to Jerne's hypothesis of immunoregulation, by a disturbance of the network of idiotype and anti-idiotype interactions.

Revised immune network concepts

The idiotype network concept needs to be revised in order to be in agreement with current data on protein/protein interactions, with the phenomenon of T and B cell recognition of idiotopes, and with the failure of certain anti-idiotypes to stimulate a given immune response. It is proposed that the distinction among Ab2 alpha, beta, and gamma is abandoned, as well as the concept of an internal image idiotope which mimics the three-dimensional shape of nominal antigen. In place of these definitions, the concept of "network antigen" is introduced. Network antigens are potentially the entire repertoire of anti-idiotypes. However, their biological effectiveness is controlled and established by two factors: (i) the affinity to the idiotype Ig receptor; and (ii) the preexisting regulatory network segment that controls the outcome of immune stimulation or suppression. Screening for effective idiotype therapeutic agents has to be done with panels of anti-idiotype and idiotype antibodies in order to establish correlations between idiotope expression and disease progression. Recognizing the importance of network segments will be the first step in the direction toward a rational design of idiotype-based therapies.

Induction of antibodies to pseudorabies virus by immunization with antiidiotypic antibodies

We have induced the expression of high titres of antibodies to pseudorabies virus (PRV) by immunization of A/J mice with polyclonal antiidiotypic antibodies directed against each of 2 BALB/c monoclonal, neutralizing anti-PRV antibodies. The anti-PRV antibodies induced by one of the antiidiotypic antibody preparations had an affinity for PRV comparable to that of the original monoclonal antibody. Mice immunized with antiidiotypic antibodies were protected to a significant degree against viral infection but the degree of protection was lower than that conferred by passive transfer of monoclonal neutralizing antibody or by immunization with attenuated virus.

Anti-idiotypic antibody with potential use as an Eimeria tenella sporozoite antigen surrogate for vaccination of chickens against coccidiosis

Anti-idiotypic antibodies were raised in rabbits against four monoclonal antibodies with specificity for the surface antigenic determinants of Eimeria tenella sporozoites, the infective stage of the coccidial parasite. Two of the monoclonal antibodies (1073 and 15-1) transferred passive protection in chickens against E. tenella infection. The polyclonal anti-idiotype antibody preparations against protective monoclonal antibodies contained specificities for the paratope-associated idiotypes of these monoclonal antibodies, as assessed by the competitive inhibition of binding of the homologous idiotype-anti-idiotype by the sporozoite antigen. Competitive inhibition of binding of homologous idiotype-anti-idiotype by the parasite antigen was not observed when the anti-idiotype antibody preparations against monoclonal antibodies 1546 and 1096 were tested. The anti-idiotype 1073 and 15-1 antibodies functioned as surrogate antigens in vivo when used for vaccination of young chickens, as evidenced by the induction of partial protective immunity against subsequent challenge infection with virulent parasites and induction of antisporozoite antibodies. These data clearly support the view that anti-idiotypic antibodies raised against the paratope-associated idiotypes can mimic pathogen antigens and therefore can provide a possible alternative approach for the vaccination of chickens against coccidiosis.

Development and characterization of an anti-idiotype antibody to the capsular polysaccharide of Neisseria meningitidis serogroup C

A monoclonal anti-idiotypic antibody (Ab2) whose antibody combining site contained a surrogate image of the meningococcal group C capsular polysaccharide was developed. To accomplish this, a monoclonal antibody against the group C capsular polysaccharide was developed by the fusion of splenocytes from mice immunized with Neisseria meningitidis group C strain MP13 with Sp2/0-Ag14 plasmacytoma cells. Monoclonal antibody 1E4, an immunoglobulin M isotype, demonstrated binding to the serogroup C polysaccharide in enzyme-linked immunosorbent assay (ELISA). Monoclonal antibody 1E4 reacted with 30 of 30 group C strains and 1 of 36 group B strains in immunodot assay, slide agglutination, inhibition ELISA, and bactericidal assay. This monoclonal antibody was selected as idiotype (Ab1) for the development of hybridomas producing an anti-idiotype antibody. One of the hybridomas developed, designated 6F9, was capable of over 70% inhibition of 1E4 in binding in the meningococcal C polysaccharide-specific ELISA. Studies with convalescent human serum demonstrated 100% inhibition of a serogroup C-specific ELISA with 200 micrograms of 6F9 per ml and 50% inhibition of this ELISA was achieved with 50 micrograms of 6F9 per ml. Monoclonal anti-idiotype antibodies (Ab3) with specificities similar to Ab1, 1E4 were generated from BALB/c mice immunized with the Ab2 (6F9). Immunization of rabbits with 6F9 resulted in an immunoglobulin G response which was significantly greater than that of control to a titer of 1:160. These studies indicate that monoclonal 6F9 contained a surrogate image on the combining antibody site which mimicked meningococcal C polysaccharide. This surrogate image is capable of evoking antibodies to the meningococcal C polysaccharide in syngenic and xenogenic species.

Selective induction of T-cell subsets by antibodies to the T-cell antigen receptor and to the subset-specific differentiation antigens CD8 and CD4

This report shows that small, resting T lymphocytes from mouse and man can be activated to proliferation and function by submitogenic concentrations of antibodies to T-cell antigen receptor in combination with antibodies to either CD8 or CD4. The combined antibodies can be applied either in solid phase condition or as soluble dimeric heteroconjugates. Activation is more efficient than by high concentrations of anti-T-cell-receptor antibody alone. Most importantly, activation is subset-specific such that the antibody to CD8/CD4 determines which T-cell subset will be induced.

Criteria to define anti-idiotypic antibodies carrying the internal image of an antigen

Anti-idiotypic antibodies which carry the internal image of a foreign antigen, i.e. so-called Ab2 beta antibodies, have been successfully used as vaccines to pathogens, as tools to isolate cellular receptors or as reagents in cancer therapy. An attempt is made to establish structural, immunochemical and and functional criteria to define anti-idiotypic antibodies of the Ab2 beta type.

Neutralisation of HIV isolates by anti-idiotypic antibodies which mimic the T4 (CD4) epitope: a potential AIDS vaccine

Polyclonal anti-idiotypic antibodies were raised in mice against anti-Leu3a, a mouse monoclonal anti-human T4 (CD4) antibody that blocks the in-vitro binding of human immunodeficiency virus (HIV) to the CD4 molecule. The anti-idiotypes recognized anti-Leu3a but not OKT4, an anti-human T4 antibody that does not inhibit HIV binding to CD4. The anti-idiotypes specifically reacted with the HIV envelope glycoprotein in solid-phase immunoassays. More importantly, the anti-idiotypes neutralised three distinct isolates of HIV-1 and one isolate of HIV-2 in a syncytial inhibition assay. These results have implications for a potential AIDS vaccine of anti-CD4 preparations to induce an anti-idiotypic response with the capacity to bind HIV at its receptor site.

A surrogate hepatitis B virus antigenic epitope represented by a synthetic peptide and an internal image antiidiotype antibody

The use of molecules that represent single, defined epitopes able to substitute for antigen (i.e. surrogate antigens) offers considerable advantages over the use of native antigen for the precise manipulation of the immune response. We have investigated the immunochemical characteristics of two types of surrogate hepatitis B surface antigen (HBsAg) epitopes: (a) linear and cyclical synthetic peptides representing amino acid residues 139-147, a hydrophilic region corresponding to part of the a determinant of the HBsAg, and (b) four monoclonal antiidiotypes raised against anti-HBs mAb, two of which behave as an internal image of an a determinant. Polyclonal anti-HBs antisera bound the monoclonal antiidiotypes with affinities of the order of 10(8)/M, and to the peptides with greater than 10-fold lower affinities. However, the levels of antibody in the polyclonal antisera for the peptides was greater than for the antiidiotypes. In inhibition RIA, the surrogate antigens show concordance in that the internal image antiidiotypes inhibit the binding of both monoclonal and polyclonal anti-HBs to the linear and cyclical 139-147 peptides. These results imply that surrogate antigens could indeed be useful as potential hepatitis vaccines, but while the antiidiotypes may stimulate B cells of higher affinity, they would react with a more restricted range of B cell reactivities than would the peptides. A future HBV vaccine may thus comprise a synthetic peptide such as cyclical 139-147 or a cluster of monoclonal internal image antiidiotypes.

Anti-idiotypic immunity in autoimmunity

It has been hypothesized that autoimmune disease may result from a derangement of the idiotype-anti-idiotype network. However, the evidence in favor of a role of anti-idiotypic immunity in autoimmunity is still scarce. For this reason, we have investigated animal models of autoimmune thyroiditis and glomerulonephritis, addressing the following questions: Are autoimmune responses idiotypically heterogeneous? Are auto-anti-idiotypic antibodies detectable in autoimmunity? Is it possible to demonstrate quantitative or qualitative changes in idiotypic and anti-idiotypic lymphocytes during the course of autoimmune disease? To date, results obtained in our laboratory may be summarized as follows: Cross-reacting idiotypes were present on human and animal autoantibodies; Circulating auto-anti-idiotypic antibodies were not detected in any of the models studied; Changes in idiotypic and anti-idiotypic lymphocytes were observed in animals with autoimmune disease.

The human anti-myelin-associated glycoprotein IgM system

Two mouse monoclonal antiidiotypic antibodies that react with human monoclonal IgM antibodies with specificity for myelin-associated glycoprotein (MAG) have been used to study the immunological specificity of the reported cross-reactions involving the anti-MAG IgM. Both of the antiidiotypic antibodies are shown to react with the combining site of their respective idiotypic IgM and to inhibit the reaction between IgM and MAG. Using these antiidiotypic antibodies as "surrogate" antigen, we have demonstrated immune cross-reactivity between MAG, a human peripheral nerve glycolipid, and a low-molecular-weight protein of human peripheral nerve myelin. In addition, we have used the two antiidiotypic antibodies to conduct a search for evidence of shared idiotypy among 34 different neuropathy-associated paraproteins. Our results provide no evidence for a neuropathy-associated idiotype, suggesting a degree of polymorphism in the human anti-MAG IgM system.

Thyroiditis

In this review, the major types of immune mediated thyroiditis are described and the etiology explained in the light of current theories of autoimmunity. Hashimoto's thyroiditis is a common autoimmune disease. The onset is gradual with patients presenting with symptoms of hypothyroidism, nonspecific symptoms of the autoimmune process itself, or symptoms relating to a goitre. The disease is usually relentless and, except in young patients, permanent replacement with thyroxine is eventually required. Silent thyroiditis is another autoimmune disease of more acute onset. The initial, thyrotoxic, phase lasting several weeks is due to release of thyroid hormone from damaged follicles, and radionuclidic scans show absent uptake. There often follows a hypothyroid phase with final recovery in most patients. Post partum thyroiditis is due to silent thyroiditis, or, less commonly, Hashimoto's thyroiditis, occurring three to six months after delivery. Subacute thyroiditis often follows a viral infection and is not thought to be an autoimmune disease. It presents with severe thyroid pain and tenderness with marked non-specific symptoms such as myalgia and fatigue. The initial, thyrotoxic, phase is also due to release of thyroid hormone, and radionuclidic scans show absent uptake. A hypothyroid phase often follows and recovery is complete. Hashimoto's thyroiditis appears to be due to a congenitally present, antigen specific, T suppressor lymphocyte defect. It is proposed that in silent thyroiditis there is a less severe Ts defect and a correspondingly greater decompensating factor. In post partum thyroiditis, this factor appears to be a general decline in T suppressor lymphocyte function after delivery. Subacute thyroiditis is not an autoimmune disease. The thyroid appears to be an "innocent bystander" in an immune mediated antiviral attack.

Immunofluorescent technique for the detection of monoclonal internal image anti-idiotypic antibodies of hepatitis B surface antigen

Monoclonal anti-idiotypic antibodies to HBsAg were screened by immunofluorescence for the presence of a subset behaving as the internal image of the original antigen. We describe the technique and the criteria fulfilled to establish that 2/6 monoclonals studied act as the internal images of the a determinant of hepatitis B surface antigen.

Correlation between G2m(n) immunoglobulin allotype and human antibody response and susceptibility to polysaccharide encapsulated bacteria

To determine whether genetic factors influence the human antibody response to polysaccharides, we correlated Ig allotypes with the concentrations of antibody to 14 bacterial capsular antigens in 130 actively immunized Caucasian adults. The 88 individuals possessing G2m(n), an allotype antigen of IgG2 subclass heavy chains, had significantly higher postimmunization antibody levels to Haemophilus influenzae type b (Hib) and 8 of 11 pneumococcal types (P less than 0.05) than the 42 lacking this antigen. For Hib, pneumococcus type 14, and meningococcus group C, an increased response was observed in IgG class but not in IgM or IgA classes of antibody. The G2m(n) positive individuals also had higher preimmunization antibody levels to most polysaccharide antigens. Total IgG2 concentrations were correlated with the mean postimmunization antibody concentrations to pneumococci (P = 0.005), but this correlation was independent of G2m(n) by multiple regression analysis. To determine if the lack of G2m(n) was associated with increased susceptibility to infection, we compared the frequencies of various Ig allotypes in 98 children infected with Hib and 98 matched controls. Caucasian children with Hib infections other than epiglottitis were significantly more likely to lack the G2m(n) allotype than controls (P less than 0.05). G2m(n) negative Caucasian children less than or equal to 18 mo old have a 5.1-fold higher risk of nonepiglottitic Hib infections than G2m(n) positive children (P less than 0.01). We conclude that allotypic variants of the gamma-2 heavy chain genes, or genes in linkage equilibrium with them, exert a regulatory influence on the caucasian antibody response to a variety of immunologically distinct bacterial polysaccharide antigens. Young Caucasian children of the low responder phenotype, i.e., those lacking the G2m(n) allotype, are genetically predisposed to Hib and perhaps other bacterial infections.

The pathogenesis of Graves' disease

The abnormally increased thyroid activity that is characteristic of Graves' disease is caused by immunoglobulins which specifically interact with the thyroid cell and stimulate it. Increases and decreases in thyroid activity in Graves' disease can be clearly related to rise and fall of these immunoglobulin-mediated activities. The level of immunoglobulin stimulatory activity can be used for prediction of the likelihood of neonatal Graves' disease and of recurrence of disease after cessation of treatment with antithyroid drugs. Investigation of patients with Graves' disease and their families has led to identification of particular human leukocyte antigens and genetically linked markers on immunoglobulins which both appear to incur increased susceptibility to certain autoimmune diseases. Differences in immune function, when compared with control populations, have been found in patients with these genetically linked markers. Protection against autoimmune disease is maintained by purposeful inhibition of any self-directed activity within each function of the immune system and by the controlling interaction of other immune functions. No single deficiency of immune function can be selected as giving the major risk of autoimmune disease, but rather a sum of relative defects resulting in an increased risk. In some patients with Graves' disease the self-protection mechanisms regain sufficient control of the immune functions to reduce the activity of the autoimmune disease, and the patient may achieve clinical remission. Often, however, there is evidence that abnormal immune activity directed against thyroid tissue has persisted with liability to recurrence of the Graves' disease.

Molecular analysis of induced idiotypes associated with autoanti-thyroglobulin

Idiotype (Id) and autoanti-thyroglobulin were induced in different strains of mice by priming with anti-Id to monoclonal anti-thyroglobulins (D8 and G4) and challenged with a subimmunogenic dose of thyroglobulin (Tg). Both D8.Id and G4.Id were induced in CBA mice by priming with the appropriate anti-Id, but only priming with anti-D8.Id also induced an increase in anti-Tg. D8.Id was induced in other strains by the same schedule but it only appeared to be associated with anti-Tg in 129 and, to a lesser extent, BALB/c mice, both of which have the allotype Iga. The extent of the overlap between the D8 Id and the anti-Tg was estimated and shown to be greatest in the CBA strain from which the D8 clone was originally derived. Spectrotypic analysis of the induced Ids in CBA mice showed that some of the D8.Id, but none of the G4.Id, was identical to the original clonotype, implying that CBA mice normally have cells which can be induced to produce D8.Id-positive autoanti-Tg, which are normally weakly expressed or regulated. The observation that anti-D8.Id priming in some strains increased D8.Id-negative anti-Tg responses suggests that the D8.Id may also be associated with anti-Tg T-cells.

T lymphocyte sensitization to HBcAg and T cell-mediated unresponsiveness to HBsAg in hepatitis B virus-related chronic liver disease

Using a newly developed indirect T lymphocyte migration inhibition test, cell-mediated immunity to HBsAg and HBcAg was directly and simultaneously examined in a total of 21 patients with HBsAg-positive chronic liver disease (CLD), and in seven subjects whose sera contained anti-HBs (2 previous acute hepatitis B; 4 hepatitis B vaccine recipients and 1 chronic active hepatitis). T cell sensitization to HBcAg was invariably detected in the HBsAg-positive CLD patients tested (12/12), whereas T cell sensitization to HBsAg was not present in any of the patients (0/21). In contrast, T cell sensitization to HBsAg was present in all anti-HBs-positive subjects. These results support the hypothesis that the cellular immune response to HBcAg, rather than to HBsAg, is implicated in the pathogenesis of HBsAg-positive CLD. Moreover, the observation that the addition of T cells from patients with HBsAg-positive CLD to T cells from anti-HBs positive subjects in a ratio of 1 to 9 reversed their sensitization to HBsAg, suggests that a hyperactivity of HBsAg-specific suppressor T cell population may be responsible for persistent HBs antigenemia.

Anti-idiotypic suppression of autoantibodies to factor VIII (antihaemophilic factor) by high-dose intravenous gammaglobulin

In two patients with high-titre autoantibodies to antihaemophilic factor (VIIIc), treatment with high-dose intravenous immunoglobulin (IVIg) resulted in rapid and prolonged, although not total, suppression of antibody. IVIg also inhibited anti-VIIIc activity in patients' plasma in vitro; IVIg and F(ab')2 fragments from IVIg inhibited anti-VIIIc activity of the IgG fraction and of the Fab'2 fragments of the IgG fraction from patients' plasma, indicating that the in-vivo effect of IVIg was due to the presence in the therapeutic immunoglobulins of anti-idiotypic antibodies against idiotypes expressed by anti-VIIIc autoantibodies. In contrast, IVIg had little or no effect on antibody titre in two haemophilic patients with anti-VIIIc alloantibodies. These observations suggest that IVIg contains anti-idiotypes against autoantibodies and may be effective in the treatment of some autoimmune diseases through idiotypic/anti-idiotypic interactions.

Antigen specific suppressor cell function in autoimmune chronic active hepatitis

An indirect migration inhibition assay has been used to show that lymphocytes from 26 of 29 patients with autoimmune chronic active hepatitis (CAH) generated T lymphocyte migration inhibitory factors (T-LIF) in the presence of liver specific protein (LSP), compared with only 1 of 21 patients with HBsAg-positive chronic liver disease and none of 19 controls. Generation of T-LIF activity in response to LSP was not observed in any of 5 patients with autoimmune thyroid disease although their T lymphocytes did generate T-LIF activity in the presence of thyroid membrane antigens. T lymphocytes from 1 patient with autoimmune liver and thyroid disease generated T-LIF activity in the presence of both LSP and thyroid membrane antigens. The generation of T-LIF activity by T cells from autoimmune CAH patients was suppressed when these cells were co-cultured in a 9:1 ratio with T cells from normal subjects and patients with HBsAg-positive chronic liver disease, but was unaffected if co-cultured with T cells from other patients with autoimmune CAH. T cells from patients with autoimmune CAH did, however, suppress the generation of T-LIF activity by T lymphocytes from patients with autoimmune thyroid disease when these cells were cultured with thyroid membrane antigens. After pretreatment with cimetidine or mitomycin-C for 30 min, T cells from normal subjects lost their ability to inhibit the generation of T-LIF activity to T lymphocytes from autoimmune CAH patients. These results are consistent with the hypothesis that there exists a defect in the specific suppressor T cell population controlling the immune response to LSP in autoimmune CAH which is unaffected by disease activity and treatment and which may be of fundamental importance in the pathogenesis of the disease.