Enhancement of the immune response to hepatitis B surface antigen. In vivo administration of antiidiotype induces anti-HBs that expresses a similar idiotype

Trichinella Spiralis-Ab3 (IgG, IgM, IgA), IL-6 and Tnf Levels in Murine Trichinellosis

The syngeneic anti-anti-idiotypic antibodies (Ab3) IgG, -IgM, and -IgA induced by polyclonal mouse anti-idiotypic antibodies (Ab2) against the rabbit F(ab) T. spiralis-Ab1, was studied. IL-6 level and cytotoxic activity (TNFα and LT) in the serum of mice infected with L1- T. spiralis or immunized with T. spiralis-Ab2 antibodies were also determined. The Ab1 antibody response was found to reflect the life cycle of the parasite. High IgA-, IgM-, and IgG-Ab1 levels, as well as corresponding levels of cytotoxic activity (62.3, 88.8 and 107.8 5/ml) and IL-6 (216, 447 and 789 U/ml) on days 10, 20 and 28 after the infection, respectivelly, were detected. The Ab3 antibody response against the polyclonal T. spiralis-Ab2, followed the classical pattern of antibody level after initial infection with an immunogen. IgM was first detected 10 days p.i., while IgA and IgG were detected 20 days p.i. Cytotoxic activity of 93.2, 245.9, and 326.7 U/ml, and IL-6 levels of 237, 304, and 487 U/ml, were detected on 10, 20, and 28 days p.i., respectivelly. Although Ab3 bound to T. spiralis-Ab2 antibodies or to L1 -T-spiralis antigen and cytotoxic activity in mice immunized with T. spiralis-Ab2 antibodies was increased, there was no protection against the parasitic infection.

Anti-idiotypic antibodies reduce efficacy of the attenuated vaccine against highly pathogenic PRRSV challenge

Background

The inability of current vaccines to provide effective protection against porcine reproductive and respiratory syndrome virus (PRRSV) infection is not fully understood. One of the reasons might be the presence of anti-idiotypic antibodies (Ab2s) to the envelope glycoprotein GP5 induced by PRRSV infection since our previous studies demonstrated the presence of auto-Ab2s (aAb2s) in pigs infected with PRRSV. To test this hypothesis, PRRSV negative piglets were injected with a monoclonal Ab2 (Mab2-5G2) and aAb2s that are specific for anti-GP5 antibody, vaccinated with the attenuated PRRSV vaccine CH-1R and then challenged with the highly pathogenic PRRSV HuN4 strain. The animals were evaluated for clinical signs, pathological changes of the thymus and lungs, viremia, levels of serum antibodies and cytokines.

Results

The piglets injected with Mab2-5G2 or aAb2, and who received the attenuated PRRSV vaccine CH-1R before challenge, produced high levels of anti-N antibodies, IL-2 and IL-4, but low levels of neutralizing antibodies. After PRRSV HuN4 challenge, the animals showed obvious clinical signs, including lung lesions, severe thymus atrophy and decreased production of IL-4 and higher level of viremia.

Conclusion

When anti-GP5 Ab2s are present, the use of attenuated PRRSV vaccine CH-1R against HP-PRRSV infection is not recommended. It can result in poor health status with pneumonia and thymus atrophy.

Immunoglobulin variable regions as idiotype vaccines

This article focuses on the use of immunoglobulin variable regions, including Id, anti-Id, anticlonotypes, and Id engineering as putative vaccines and vaccine strategies for infectious diseases; and specific discussion of Id systems involving antigenic determinants associated with potentially pathogenic organisms.

Biological mimicry of the bluetongue virus core protein VP7 by rabbit anti-idiotype

A subpopulation of rabbit polyclonal anti-idiotypic antibody (anti-Id) was previously produced to a murine monoclonal antibody (mAb) (M1875) specific for the bluetongue virus core protein VP7. In this report, mimicry of VP7 by this anti-Id (designated RAb2-A) was functionally analyzed through immunization of Balb/c mice with RAb2-A or purified VP7. Animals immunized with RAb2-A were able to produce an M1875-like Ab3 antibody response with idiotype and epitope specificity resembling that of M1875 without subsequent exposure to the nominal antigen. This conclusion was supported by experiments showing that the RAb2-A-induced Ab3 antibodies (i) reacted specifically with the immunizing anti-Id; (ii) were capable of binding VP7; (iii) inhibited M1875 from binding to VP7; and (iv) inhibited M1875 from binding to RAb2-A. Similarly, mice immunized with purified VP7 also produced antibodies that exhibited characteristics such as idiotype and epitope specificity in common with M1875. No antibody response to VP7 was detected in control groups of mice immunized with either normal rabbit IgG or BHK-21 cell components. Therefore, it can be concluded that rabbit anti-Id RAb-2-A mimics an M1875-defined VP7 epitope sufficiently to function as a surrogate antigen for inducing an anti-bluetongue virus response.

Evidence that two distinct populations of rabbit anti-idiotypic antibodies are induced by three monoclonal antibodies specific for bluetongue virus core protein VP7

Three groups of anti-idiotypic antibodies (anti-Id or Ab2), designated RAb2-A, RAb2-B1, and RAb2-B2, were isolated from rabbit antiserum raised against three monoclonal antibodies (mAbs) (M1875, M1877, and M1886) specific for the bluetongue virus core protein, VP7. RAb2-A was specific for the idiotype of M1875. RAb2-B1 and RAb2-B2, isolated through the M1877 and M1886 affinity columns, respectively, were directed against the common idiotype that is shared by M1877 and M1886 and therefore classified in the same population (RAb2-B). Further characterization revealed that the two anti-Id populations, RAb2-A and RAb2-B, were significantly different. RAb2-A was an Ab2 beta type of anti-Id since (i) its reaction with M1875 was inhibited by the antigen; (ii) it inhibited the M1875-VP7 interaction; and (iii) it elicited anti-VP7 antibody response in Balb/c mice. In contrast, RAb2-B may represent an Ab2 alpha type of anti-Id since its reactions with M1877 or M1886 were not inhibited by the antigen, even though it inhibited mAbs from binding to the antigen. These results indicated that RAb2-A and RAb2-B represent two distinct populations of anti-Ids to anti-VP7 mAbs with similar epitope specificity.

Induction of antibodies to the bluetongue virus core polypeptide VP7 in sheep by internal image rabbit antiidiotypic antibodies

We previously generated rabbit polyclonal antiidiotypic antibody (anti-Id) to a murine monoclonal antibody (M1875) specific for the bluetongue virus core protein VP7, and demonstrated that this anti-Id (designated RAb2-A) had the characteristics of an internal image anti-Id (Ab2 beta). In this communication, RAb2-A was used to induce immune responses in sheep and the responses were compared to immunization with VP7. The immune sera were tested for the presence of anti-VP7 antibodies and the expression of the Id of M1875. Animals immunized with RAb2-A were able to produce M1875-like antibody responses, i.e., they recognized the same or a similar epitope as M1875 and possessed the M1875 Id, without subsequent exposure to the original antigen. This was demonstrated by showing that antibodies induced by RAb2-A (i) reacted specifically with the immunizing anti-Id, (ii) were capable of binding VP7, (iii) inhibited M1875 from binding to VP7, and (iv) inhibited M1875 from binding to RAb2-A. Animals immunized with purified VP7 produced antibodies that possessed the epitope and idiotope specificity of M1875. No antibody responses to VP7 were detected in control animals immunized with either rabbit anti-Id to the pseudorabies virus glycoprotein gII or BHK-21 cell proteins. We conclude that rabbit anti-Id RAb2-A serologically mimics an M1875-defined VP7 epitope sufficiently to function as a surrogate antigen for inducing anti-bluetongue virus VP7 responses.

Moloney leukemia virus-induced cell surface antigen mimicry by monoclonal antibodies

We have investigated antigen-independent modulation of immune responses by monoclonal antibodies directed against both viral and nonviral antigens. BALB/c mice were immunized with monoclonal IgM (i.e. Ab1) specific for either Moloney murine leukemia virus-induced cell surface antigen (MCSA) or the hapten 2,4-dinitrophenyl (DNP). Injection with either Ab1 activated a functional idiotypic (Id) network as evidenced by production of both anti-Id (Ab2) antibodies and anti-anti-Id (Ab3) antibodies. A subset of induced Ab3 (designated Ab1'), exhibited specificity for antigen (virus or DNP). In mice immunized with anti-Id antibodies (Ab2), production of Ab3 and Ab1' was also observed. In the MCSA system, antibody-induced Ab1' responses were effective in protecting mice from tumor development upon subsequent challenge with live virus. Furthermore, antigen-independent modulation of immunity to both viral and nonviral antigens was found to be thymus-dependent. Similar findings in other viral systems suggest that antibody-induced activation of Id networks may prove a viable alternative vaccine strategy that can elicit antigen-specific responses, and in some cases protection, in the apparent absence of exposure to antigen.

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.

Production of monoclonal anti-idiotype antibodies which mimic an M-like protein of Streptococcus equi

Rat monoclonal anti-idiotype antibodies (mAb2) were raised against two mouse monoclonal antibodies (mAb1), 1D10 and 2A6, with specificity for the M-like protein of Streptococcus equi. The capacity of the mAb2 to inhibit the binding between the corresponding mouse mAb1 against which the mAb2 were raised and the M-like protein was investigated in an inhibition EIA. One of the ten mAb2 examined, namely 5D1 (anti-mAb1 1D10), was able to inhibit this binding. The mAb2 5D1 bound to the mAb1 1D10 in such a way as to completely inhibit the subsequent binding of the M-like protein antigen to the paratope of the mAb1 1D10. The mAb2 5D1 is likely to represent a true image of the M-like protein antigen and may thus be described as an Ab2 beta anti-idiotype antibody.

Mouse monoclonal anti-idiotypic antibodies to HIV p24: immunochemical properties and internal imagery

Two mouse monoclonal antibodies (VIC5 and VIC6; referred to as Ab1) reacting with the p24 core antigen of HIV-1 were used to produce mouse monoclonal anti-idiotypic antibodies (Ab2). Six anti-idiotypic antibodies were characterized. The five anti-idiotypic antibodies directed against VIC6 partly competed which each other and thus defined a set of overlapping idiotypes on Ab1. All 6 Ab2s inhibited the binding of the corresponding anti-p24 antibody to antigen, although four (W1, Y16, Y6, X14) were markedly more inhibitory than the remaining two (G6, Y11). All six Ab2s were antigen-inhibitable; however the interaction of G6 and Y11 with Ab1 was blocked with considerably less soluble p24 antigen than the remaining four. Correspondingly, G6 and Y11 had lower affinities for Ab1 than did W1, Y6 and X14; the affinity index of Y16 was equivalent to that of Y11. None of the Ab2s reacted with H or L chains of Ab1 after reduction on SDS-gels. Similarly, both Ab1s failed to react with the H or L chains of Ab2. These criteria appeared to define at least four of these Ab2s as internal image antibodies whose image is composed of both H and L chains. The anti-idiotypic antibodies were injected either individually or as a combined preparation of all 6 into syngeneic mice and Porton rats. Despite the presence of anti-anti-idiotypic antibodies (Ab3) in these animals, when used individually no antigen-specific antibodies were found. A small response to p24 antigen was induced in 3 of 6 mice using preparations containing all 6 anti-idiotypes.

Collagen-induced arthritis suppressed with monoclonal anti-idiotypic antibody

In foregoing work, we identified at least 5 distinct epitopes on human type II collagen (CII), using 8 murine monoclonal antibodies (mAb) against human CII, and suggested that a species-nonspecific epitope on CII recognized by anti-CII mAb termed 1-5 is an arthritogenic epitope. We also found that antibody response against a selected epitope of human CII could be induced by immunization with rabbit anti-idiotypic (Id) antibody against anti-CII mAb. The author developed and characterized monoclonal anti-Id antibodies against 1-5 mAb recognizing a putative arthritogenic epitope. The author also investigated whether the anti-Id mAb could regulate antibody response directed against a selected epitope recognized by 1-5 mAb, and the induction of collagen-induced arthritis in DBA/1J mice. DBA/1J mice intravenously preinjected with anti-Id mAb to 1-5, did not produce anti-CII antibody expressing 1-5 Id upon immunization with human CII. Furthermore, as the development of collagen-induced arthritis (CIA) in DBA/1J mice pretreated with anti-Id mAb to 1-5 was significantly suppressed, anti-Id mAb will be a useful tool for studying the regulation of antibody response to a selected epitope. This study lends support to our hypothesis that the 1-5 epitope is an arthritogenic epitope.

Monoclonal anti-idiotype induces antibodies against bovine Q17 rotavirus

This study describes, for the first time, the production and use of an "internal-image" anti-idiotypic monoclonal antibody (MAb) to elicit a rotavirus-specific antibody response. An immunoglobulin G2a MAb, designated RQ31 (MAb1), specific for the outer capsid protein VP4 of bovine Q17 rotavirus and capable of neutralizing viral infection in vitro was used to generate an anti-idiotypic MAb (MAb2). This MAb2, designated RQA2, was selected by enzyme-linked immunosorbent assay (ELISA) using F(ab')2 fragments of RQ31. RQA2 (MAb2) inhibited the binding of RQ31 (MAb1) to the virus but had no effect on the binding of other rotavirus-specific MAbs. The MAb2 also inhibited virus neutralization mediated by MAb1 in a dose-dependent fashion. Naive guinea pigs immunized with the MAb2 produced anti-anti-idiotypic antibodies (Ab3) that reacted with bovine Q17 rotavirus in an ELISA and neutralized rotavirus infection in vitro. The Ab3 response was characterized as MAb1-like because the Ab3 recognizes only the Q17 and neonatal calf diarrhea virus rotavirus strains in ELISA, as did RQ31 (MAb1). The Ab3 response also possessed two other characteristics of RQ31: the abilities to bind the 1.36 (double-capsid) but not the 1.38 (single-capsid) purified rotavirus fraction in ELISA and to immunoprecipitate the VP4 rotavirus protein.

Evidence that autologous idiotypic regulation of anti-arginine-glycine-aspartic acid autoantibodies may influence development and progression of syphilitic lesions in infected rabbits

The 83-kDa receptor protein of Treponema pallidum (TpN83) recognizes and binds fibronectin (Fn) at the amino acid sequence RGD site. By using experimentally infected animals, we have demonstrated that immunoglobulin G antibodies to this antigen and autoantibodies to the RGD site of Fn are putative components of immune complexes. This, and other findings, led us to initially hypothesize that anti-idiotypes (anti-Id) of an anti-TpN83 response are autoantibodies to RGD. Alternatively, we reasoned that if anti-Fn autoantibodies played a role in the pathogenesis of syphilis, then down-regulation of such a response by the Id network might directly affect progression of the disease. To test the hypothesis, rabbits were immunized with either affinity-purified TpN83 antigen or the synthetic Fn-7 peptide, KYGRGDS, and subsequently challenged with T. pallidum. Compared with results obtained with unimmunized, control rabbits, accelerated lesion development was noted in the rabbits immunized with TpN83. Pronounced, though unexpected, differences with respect to lesion development and progression were noted in the animals immunized with Fn-7 and then challenged intravenously; a minimal number of lesions appeared with a delayed onset. These lesions, like the localized chancres seen following intradermal challenge, were smaller and minimally ulcerated, and they healed rapidly. The Fn-7-immunized rabbits all differed from the controls in that anti-Id to anti-RGD F(ab')2 were demonstrable within 4 weeks following infection; decreases in anti-Fn autoantibody levels were associated with concomitant increases in anti-Id levels. Immunoglobulin Gs (anti-Id) from these animals following elution from anti-RGD F(ab')2 immunoaffinity columns also reacted with affinity-purified TpN83 antigen in immunoassays. These results suggest that down-regulation of autoreactive clones by manipulation of the idiotypic network in experimental syphilis warrants further investigation.

Anti-idiotype-based vaccines against biological toxins

Biological toxins produced by living organisms represent one of the major sources of contamination of stored grain and agricultural products, and other food sources. The majority of these biological toxins are highly lethal, nonproteinaceous low-molecular-weight chemical compounds which exert their potent toxicity through a variety of mechanisms. Because of their small size, they generally do not induce a significantly high affinity protective antibody response upon toxin exposure, even when conjugated to large protein carriers which enhance their immunogenicity. Moreover, the very toxic nature of biological toxins precludes their use as immunogens in the induction of protective immunity. To circumvent this difficulty, an attempt was made to develop antibody (anti-idiotype)-based vaccines against a protein synthesis inhibitor, the trichothecene mycotoxin T-2, and the sodium channel blockers tetrodotoxin and saxitoxin. Protective monoclonal antitoxin antibodies were first generated and then used to induce specific monoclonal anti-idiotype antibodies. Specific anti-idiotype antibodies were assessed for their ability to induce in vivo protective immunity against toxicity.

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.

Current approaches to vaccine preparation

Numerous conventional vaccines for animal use are currently available, and many of these vaccines have been instrumental in the control of infectious diseases of major economic importance. A vaccine has even been instrumental in global eradication of smallpox, an important human disease. However, many of the current vaccines are deficient in efficiency, potency, or safety. It has been recognized that the conventional methodologies are a limitation to further vaccine development. Introduction of monoclonal antibodies, recombinant DNA, and protein engineering techniques has facilitated a rather rapid increase in the knowledge of pathogenetic mechanisms, as well as of protective antigens at the molecular level. This knowledge provides the basis for development of a new generation of vaccines. As a rule, these vaccines contain purified immunogens, or even isolated epitopes, identified and prepared by molecular biological techniques. The efforts to find better delivery systems and better adjuvants accompany the research on vaccines.

Administration of noninternal image monoclonal anti-idiotypic antibodies induces idiotype-restricted responses specific for human immunodeficiency virus envelope glycoprotein epitopes

A mouse monoclonal anti-idiotypic antibody (anti-Id), designated MC1, was generated against chimpanzee antibodies specific for a synthetic peptide corresponding to a native epitope associated with gp41 of human immunodeficiency virus (HIV). This anti-Id recognized a shared idiotope/idiotype (Id) on a second chimpanzee anti-gp41 peptide preparation but failed to detect this Id on rabbit and mouse anti-gp41 peptide antibodies induced by immunization with the gp41 synthetic peptide. The chimpanzee Id-MC1 reaction was not inhibited by either synthetic peptide or recombinant gp160 suggesting that MC1 exhibits noninternal image, Ab-2 alpha-like characteristics. Immunization of syngeneic Balb/c mice with MC1 induced an antigen-positive (Ag+) response capable of binding the synthetic peptide, recombinant gp160, and gp41, whereas MC1-immunized rabbits did not produce any detectable anti-peptide and/or anti-HIV envelope glycoprotein antibody response. The MC1-induced anti-Id response (Ab-3) in both mice and rabbits expressed a similar Id with the Ab-1, which is not normally expressed in the anti-gp41 peptide antibody response induced by the nominal antigen in Balb/c mice and in rabbits. Together, these studies indicate that a mouse monoclonal anti-Id of the Ab-2 alpha class can induce an anti-HIV response specific for a gp41 epitope defined by a synthetic peptide, which does not cross species barriers.

Idiotypic cascades associated with the CD4-HIV gp120 interaction: principles for idiotype-based vaccines

Idiotypes (Id) are antigenic determinants expressed on the variable (V) region of the immunoglobulin molecule. Id-bearing antibodies, or Ab-1, are produced upon stimulation with a given antigen. Ab-1 may elicit the production of anti-idiotypic antibodies (anti-Id) or Ab-2. The anti-Id also expresses Id determinants and may in turn elicit the production of anti-anti-Id or Ab-3. The production of Ab-1, Ab-2, and Ab-3 responses resulting from stimulation with the antigen is representative of components within an Id cascade. The existence of this Id cascade is the basis for the development of Id based strategies for controlling the immune response to infectious agents and tumors. In this review we will focus on several aspects regarding the Id cascades that may be operational during the immune response to the human immunodeficiency virus (HIV). In light of several studies which suggest the existence of Id-anti-Id interactions operating during the course of HIV infection, we will discuss the potential applications of Id based strategies in manipulating the immune response to HIV.

Parasite exposure elicits a preferential T-cell response involved in protective immunity against Eimeria species in chickens primed by an internal-image anti-idiotypic antibody

Polyclonal anti-idiotype 1073 (anti-Id 1073), raised against a monoclonal antibody specific for the protective epitope(s) of Eimeria tenella sporozoites, induced cell-mediated immune (CMI) responses in bursectomized chickens. Whereas alhydrogel-adsorbed anti-Id 1073 was sufficient to engender the CMI response at 4 h after injection, induction of the CMI response at 24 h required both alhydrogel and muramyl dipeptide sterol. Exposure of immunized chickens to live parasites prompted a dichotomous effect on the CMI response engendered by anti-Id in that the 4-h CMI response was preferentially stimulated and the 24-h CMI response was down regulated. Both types of CMI response were transferable to naive chickens by T cells from anti-Id 1073 immune donors or by parasite-specific T cells from clones 21 and 27. These T-cell clones were generated from chickens immunized by repeated infections with E. tenella and showed in vitro proliferative responses to anti-Id 1073. The abilities of T cells from clone 21 to selectively transfer the 4-h CMI response and to generate gamma interferon to activate macrophages for their cytotoxic effects on Eimeria sporozoites correlate with the preferential stimulation by parasites of the 4-h CMI response in chickens immunized with anti-Id 1073. These data show that anti-Id 1073 mimics the protective epitope(s) of the parasite and primes chickens for protective CMI responses. Cytotoxic T cells, equivalent to the mammalian T-cell subset of the Lyt2+ phenotype, appear to be the primary effector T cells in the CMI response engendered by anti-Id 1073 against Eimeria parasites.

Anti-idiotype modulation of the in vitro immune response to hepatitis B surface antigen (HBsAg) following remote infection by hepatitis B virus in man

An antigen-inhibitable Ab-2 that exhibits internal image activity will selectively stimulate the in vitro production of anti-HBs in individuals with remotely established immunity to hepatitis B virus. This response is seen (1) in the absence of a polyconal increase in total IgG, (2) with the F(ab')2 component of the Ab-2, (3) in cultures depleted of T-cells, and (4) in the absence of stimulation by antigen. This observation demonstrates that the Ab-2-mediated stimulation of specific IgG production may be an important regulatory function in man.

Methods for generating reagents to examine idiotype networks within antiviral immune responses

The use of anti-idiotypic antibodies to examine and/or modulate the immune response to various viral antigens has the potential to be of use in many diverse systems. This paper details the method and immunologic parameters used in our laboratory to generate and characterize anti-idiotypic antibodies (anti-Id or Ab-2) with specificity for antibodies directed against viral antigens. These anti-Id reagents have been used in our laboratory for studies involving the immune responses to hepatitis B virus and simian virus 40, which we describe here, as well as herpes simplex virus, and the human immunodeficiency virus. We have utilized these anti-Id reagents to examine the fine specificity of the idiotypes on antiviral antibodies in these systems and have attempted to modulate or induce specific antiviral immune responses. It is anticipated that the methods described herein will be helpful in analyzing the immune response in other viral systems including studies involving viral-receptor interactions.

The specific pathogen-free human: a new frontier in oral infectious disease research

The indigenous flora acts as a deterrent to the establishment of some pathogenic species. We propose that advances in oral health research will lead to control of oral infections by altering the indigenous microflora to create a specific pathogen-free human. Investigations of important endogenous and exogenous factors which affect the oral flora and the interactions among these parameters, in health and disease, will have to be undertaken for this goal to be achieved. Several approaches to produce a specific pathogen-free human include: (1) introduction of individual or collective moieties which inhibit detrimental interactions on a genetic and molecular level; (2) genetic modification of salivary flow and protein composition by use of transgenic techniques; (3) therapeutic replacement with altered bacterial strains; (4) alteration of host immune responses to produce specific isotype immunity at the most appropriate time in the ontogeny of the oral environment; (5) production of isotype and/or antigen-specific regulatory molecules at the most appropriate time in development; (6) use of synthetic vaccines; (7) genetic alteration or replacement of cells with defective protective capabilities; and (8) use of anti-idiotype vaccines.

Expression and characterization of hepatitis B virus surface antigen polypeptides in insect cells with a baculovirus expression system

The baculovirus Autographa californica nuclear polyhedrosis virus was used as an expression vector to produce hepatitis B virus surface antigen with and without the pre-S domain. The S gene product was expressed as both fusion and nonfusion polypeptides. No difference was observed in the posttranslational modification of the fusion and nonfusion polypeptides. The S proteins were not secreted into the medium but were inserted into the endoplasmic reticulum, glycosylated, and partially extruded into the lumen of the endoplasmic reticulum as 22-nm lipoprotein particles. The oligosaccharide chains on the insect cell-derived S protein were of the N-linked high-mannose form, in contrast to the complex-type oligosaccharides detected on plasma-derived hepatitis B virus surface antigen. The pre-S-S polypeptides were inserted into the endoplasmic reticulum, glycosylated, and modified by fatty acid acylation with myristic acid. A procedure was developed to purify the S protein from cellular membranes by using detergent extraction and immunoaffinity chromatography. The purified S protein was in the form of protein-detergent micelles and was highly antigenic and immunogenic.

Antiidiotypic antibody vaccine in murine Schistosomiasis mansoni comprising the internal image of antigen

This study presents the characterization of an experimental immunotherapeutic approach for schistosomiasis utilizing antiidiotypic antibodies. Antiidiotype (31-3B6) was generated in rabbits using a protective murine monoclonal antibody 31-3B6 which recognizes a 68,000-D molecular mass glycoprotein present in extracts of Schistosomiasis mansoni adult worm homogenetics. Immunization of mice with antiidiotype (31-3B6) before S. mansoni cercariae infection resulted in protection levels ranging from 16 to 41% depending on the route of administration of antiidiotypic antibody and the use of adjuvant. Levels of protection as high as 25% could be obtained with a single injection of antiidiotype (31-3B6) without the use of adjuvant. Animals noted to be resistant to infection with S. mansoni cercariae were also noted to exhibit a humoral immune response that bound components of S. mansoni adult worm homogenetics. This induced antiantigen immune response was shown to bind to the surface of S. mansoni schistosoma by indirect immunofluorescence. Further characterization of the induced antiantigen response showed that a portion (3-32%) of the induced humoral immune response portrayed the binding specificities of the murine monoclonal antibody 31-3B6. The data indicate that antiidiotype antibodies generated utilizing defined monoclonal antibodies can act as surrogate antigens in the protection of infection in schistosomiasis.

Anti-idiotypic antibodies to rubella virus

Polyclonal and monoclonal anti-idiotypic (Ab2) and monoclonal anti-anti-idiotypic antibodies were generated against rubella virus-specific neutralizing and/or hemagglutination inhibiting monoclonal antibodies. None of the characterized Ab2's recognized the putative rubella virus receptor.

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

Syngeneic monoclonal anti-idiotypic antibodies were raised against idiotopes on neutralizing monoclonal antibodies with specificity for feline leukemia virus and canine parvovirus. The anti-idiotypic antibodies were shown to recognize paratope-related private idiotopes. Mice were injected with the monoclonal anti-idiotypic antibodies and the sera of these mice were screened for antiviral reactivities. Antibodies to both feline leukemia and canine parvovirus could be induced as determined by ELISA. These results suggest that anti-idiotypic antibodies which detect private idiotopes and thus do not represent internal images of viral antigens may be considered as candidates for the induction of antiviral immunity.

Towards an idiotype vaccine against mammary tumors. Induction of an immune response to breast cancer-associated antigens by anti-idiotypic antibodies

Previously we have reported on the production of two sets of human monoclonal antibodies reacting with mouse mammary tumor virus (MMTV) and human mammary tumor virus (HuMTV) cross-reacting antigens. B11 is a monoclonal IgG generated by the human-human hybridoma technique using axillary lymph node of breast cancer patients. 4.6/6 is a monoclonal IgG established by the mouse-human hybridoma procedure using peripheral blood lymphocytes of a healthy investigator working with the breast cancer cell line T47D which secretes HuMTV antigens. Two anti-idiotypic (Id) antibodies were produced by immunizing rabbits with B11 or 4.6/6. Following exhaustive adsorption on unrelated human-Ig, fetal calf serum and purification on B11 or 4.6/6 affinity columns, the anti-Id antibodies were shown to react specifically with their respective Id. The binding of these anti-Id antibodies to the respective Id was specifically inhibited by prior incubation of the Id with MMTV and/or HuMTV antigens. Rabbit anti-B11 and rabbit anti-4.6/6 anti-Id antibodies were employed to immunize female C3Heb mice. Following immunizations, humoral and cellular immune responses to MMTV-related antigens could be demonstrated. The sera of the mice contained anti-MMTV antibodies and delayed-type hypersensitivity was specifically expressed when irradiated cells of the Mm5MT line (which carry surface MMTV antigens) were injected. Our results support the notion that anti-Id antibodies harboring the internal image can immunize animals against tumor cells bearing on their surface viral-associated antigens.

Idiotypes, anti-idiotypes, and autoimmunity

Over the past two decades it has become clear that the ability of a host to generate antibodies against a wide variety of potential antigens is due to structural diversity in the antibody molecule within the variable region. This diversity results in sites within the molecule that are themselves immunogenic. These immunogenic sites are called idiotopes, and the collection of idiotopes on a single antibody molecule determines that antibody's idiotype. The idiotype of an antibody molecule is defined serologically by a second antibody termed an anti-idiotype. Anti-idiotypic antibodies can recognize antibody molecules bearing similar or identical structures within the variable regions, which are often on or near sites of antigen binding. Investigation into the nature of idiotype and anti-idiotype interactions has increased our knowledge of antibody structure, antigen-antibody interactions, the regulation of antibody production, and the nature of autoimmune disorders. This review will discuss the nature of idiotypes and anti-idiotypes and their potential role in the diagnosis, management, and treatment of autoimmune, infectious, and malignant diseases.

Anti-idiotypic antibodies as immunogens: idiotype-based vaccines

Numerous studies have documented that antibodies may regulate the immune system and form the basis of vaccines, namely anti-idiotype vaccines. Antibodies carry individual idiotype antigenic determinants against which antibodies can be formed. When the anti-idiotype recognizes the same site that recognizes the primary antigen, a mirror image or combining site antibody may be generated. Other anti-idiotypes which recognize non-combining antigenic determinants have also been used. The evidence is reviewed for the existence of a broad range of anti-idiotypes and details are given of how an anti-idiotype vaccine based on the hepatitis B surface antigen has protected against virus challenge in the most relevant animal model system, namely the chimpanzee. Furthermore, the definition of the CD4 molecule as the conserved binding site for all known human and similar immunodeficiency viruses, (in marked contradiction to their varied neutralizing properties) has led to the raising of anti-idiotypes in mice based on the CD4 receptor which have the capacity to neutralize a broad range of isolates.

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.

Selectivity in IgG subclass response to hepatitis B vaccine in infants born to HBsAg-positive mothers

IgG subclasses of antibodies to the hepatitis B surface antigen (HBsAg) in sera from 40 healthy infants immunized with the vaccine against hepatitis B virus (HBV) were detected using an enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies. The infants were born to asymptomatic HBsAg-positive mothers. Total serum IgG subclasses were also tested to exclude a deficiency of certain subclasses in these infants but their distribution was the one expected according to age. In contrast, IgG subclass antibodies to HBsAg were predominantly IgG1 and IgG4. The collected data indicate that infants produce significantly higher levels of IgG1 and IgG4 than IgG2 and IgG3 in response to the vaccine for HBV. The IgG4 response to anti-viral vaccinations is uncommon. The role of that IgG4 subclass is not yet clear: even if an anaphylactic role was suggested, no adverse reactions were observed in vaccinated children.

Recognition of several idiotopes on a monoclonal anti-hepatitis B virus surface antigen using monoclonal anti-idiotypic antibodies

A monoclonal murine antibody H3F5 directed to the a determinant of hepatitis B surface antigen (HBsAg) was used to raise several monoclonal anti-idiotypes. Cross-blocking experiments between the anti-idiotypes and the patterns of inhibition produced by a number of other monoclonal anti-HBsAg, generated in the same fusion as H3F5, identified three idiotopes on H3F5 which were shared to varying degrees with the other anti-HBsAg monoclonals. One behaved as a dominant cross-reacting idiotope (CRI) in that it appeared strongly in 5/7 monoclonal idiotypes. The CRI could represent an important target for regulation by anti-idiotope. Monoclonal antibodies have many advantages over polyclonal sera in the detailed analysis of idiotope structures.

A common anti-DNA idiotype and other autoantibodies in sera of offspring of mothers with systemic lupus erythematosus

Since the immune response in fetuses of mothers with systemic lupus erythematosus (SLE) is unknown, we investigated sera from six mothers and their paired offspring by enzyme-linked immunosorbent assay (ELISA) for the presence of a common anti-DNA idiotype (16/6 Id) and, as control, for the presence of an unrelated public idiotype of antibody to hepatitis B surface antigen (HBsAg). In addition, maternal as well as fetal sera were evaluated for the presence of antibodies to ssDNA, dsDNA, poly(I), poly (dT), RNA, cardiolipin, total histones and the presence of lupus anticoagulant. Clinically active SLE mothers showed in general increased IgG and, to a lesser extent, IgM autoantibody activity. Circulating lupus anticoagulant was detectable in clinically active mothers only. All offspring of clinically active SLE mothers showed increased IgG autoantibodies to a variety of antigens, while IgM antibodies were detected in only one fetus. In contrast, fetuses of clinically inactive mothers showed only minor IgG activity. Common anti-DNA-idiotype (16/6 Id) activity also correlated with disease activity in both maternal and fetal compartments. One clinically active mother was 16/6-negative; her offspring was, however, positive, indicating de novo production of the idiotype by the fetus. In contrast, a control anti-HBsAg idiotype was not detected in either maternal or fetal sera. It therefore appears that offspring of clinically active SLE mothers serologically reflect maternal disease activity. Furthermore, autoantibodies and common idiotype of autoantibodies can be found within the fetal compartment even in the absence of such antibodies in the maternal serum. Discrepancies between mothers and offspring in IgM-autoantibody levels and the presence of new idiotypes in fetuses are indicative of fetal de novo autoantibody production.

Interactions between hepatitis B virus and polymeric human serum albumin. II. Development of syngeneic monoclonal anti-anti-idiotypes which mimic hepatitis B surface antigen in the induction of immune responsiveness

We used monoclonal anti-idiotypes (anti-Id) 63.14, previously shown to mimic polymeric human serum albumin (polyHSA) and bind its receptor on hepatitis B surface antigen (HBsAg), to produce syngeneic monoclonal anti-anti-Id (Ab3) which could bear the internal image of HBsAg and mimic its immunogenicity in vivo. Nine hybridomas obtained from spleen cells of BALB/c mice immunized with 63.14 were isolated, which were able to inhibit the binding of alkaline phosphatase-conjugated 63.14 to HBsAg. Both direct and competition enzyme-linked immunosorbent assay (ELISA) showed that 4 of these clones were able to mimic HBsAg since they reacted with polyHSA and inhibited the binding of monoclonal and polyclonal anti-HBsAg to the viral antigen. To determine whether these Ab3 could induce an immune response against HBsAg in vivo, we injected a series of rabbits with Ab3 G11 or HBsAg and tested their sera after the second boost. ELISA, radioimmunoassay and Western blot experiments showed that G11 was as effective as HBsAg in inducing a specific anti-HBsAg immune response. These data indicate that our Ab3 can mimic HBsAg both in vitro and in vivo and might be useful as alternative vaccine for HBV infection.

An enzyme-linked immunosorbent assay (ELISA) for the detection of IgG and IgM anti-idiotypes directed against anti-HBs molecules

A simple and specific enzyme-linked immunosorbent assay (ELISA) has been developed to detect circulating IgG and IgM anti-idiotypic antibodies directed against anti-HBs molecules using 96-well polyvinyl microtitre plates as the solid phase and HRPO-labelled goat anti-HBs as conjugate. Anti-idiotype reactions were observed in the supernatant portion after precipitation of immune complexes from sera with polyethylene glycol 6000 (PEG). Both IgG and IgM with anti-idiotype activity were detected concurrently in HBsAg-positive sera from HBV-infected patients and asymptomatic HBV carriers. Anti-idiotype activity was absent in HBsAg-negative sera from healthy persons, and in patients with non-A, non-B hepatitis and viral hepatitis A. However, such antibodies could be demonstrated in the sera of two out of eight HBsAg vaccine recipients negative for anti-HBs but in none of 11 recipients positive for anti-HBs after receiving a booster immunising dose of HBsAg vaccine. Those sera showing positive anti-idiotype reactions were free from rheumatoid factor and HBsAg/IgM or HBsAg/IgG complex activity. An analysis of anti-idiotype positive sera for anti-HBs, HBeAg and HBV-specific DNA-polymerase activity demonstrated these markers in 20%, 30% and 60% of cases, respectively. The presence of anti-idiotypic antibodies was presumed to permit a more active multiplication of hepatitis B virus.

Effect of syngeneic anti-idiotypic antibody on influenza virus neuraminidase antibody response

Influenza viruses possess two major surface glycoproteins - hemagglutinin (HA) and neuraminidase (NA). Py203, a monoclonal antibody (Ab) specific for the neuraminidase of the PR8 (H1N1) influenza virus, was used to prepare syngeneic monoclonal anti-idiotypic (anti-Id) Abs. From a BALB/c mouse immunized with Py203 (anti-N1), we obtained RM1, a monoclonal anti-Id Ab. The Py203-Id was detected in a significant fraction of immunoglobulins (Igs) in the primary and secondary responses elicited by PR8 (H1N1) and X31 (H3N2) viruses. In animals injected with minute amounts of RM1 and subsequently boosted with an identical dose of RM1, no detectable anti-NA activity was noted, but a significant increase in Py203-Id-bearing Igs was observed. In the sera of animals injected with minute amounts of RM1 and subsequently boosted with PR8 (H1N1) or X31 (H3N2) viruses, an increase in anti-NA activity and in the level of Py203-Id was noted. Animals injected with large amounts of RM1 and boosted with PR8 and X31 showed a marked suppression of the Py203-Id but no alteration in the anti-NA response. The anti-Id recognizes an idiotope (the Py203 idiotope) shared by antibodies specific for the N1 and N2 neuraminidase variants.

Monoclonal antibodies specific for Sendai virus. II. Production of monoclonal anti-idiotypic antibodies

The monoclonal antibodies A and B specific for the HN molecule of Sendai virus were used to induce polyclonal and monoclonal anti-idiotypic antibodies. No response was observed in allogeneic Lewis rats, low responses in syngeneic LOU rats, and high responses in allogeneic BN rats and xenogeneic Balb/c mice. The monoclonals A and B share a similar or identical idiotype, since polyclonal anti-idiotypic antisera to antibody A cross-reacted completely with antibody B and vice versa. The same was found with the three monoclonal anti-idiotypes 1, 2, and 3 elicited in a BN rat or in Balb/c mice. None of the polyclonal or monoclonal anti-idiotypes reacted with other monoclonal antibodies specific for Sendai virus, even when these recognized the same epitope as antibodies A and B. The monoclonal anti-idiotypic antibodies could be used to induce anti-Sendai antibodies in BN rats.