Capillaria hepatica: Granuloma formation to eggs: III. Anti-immunoglobulin augmentation and reagin activity in mice

Sera from mice with primary and secondary Capillaria hepatica egg granulomas were examined for 48-hr homologous PCA activity and for the presence of IgM, IgG₁, and IgG₂ using a microtiter anti-globulin augmentation assay following indirect hemagglutination testing. All three antibody types assayed were present. Secondary granuloma formation produced an antibody response characterized by the initial production of IgM followed by IgG₁ and IgG₂ during the latter phase of the test period, however primary granulomatous sera demonstrated a more varied antibody response with the presence of all three during the entire test period. Forty-eight-hour PCA tests demonstrated the presence of reagin activity in sera from granulomatous and infected mice. Reagin activity occurred more frequently in primary than secondary granulomatous mice. These studies thus confirm the presence of antibody during granuloma formation to C. hepatica eggs and conclusively demonstrate the presence of at least two classes of antibody.     

Relationships between cell-mediated immunity and the IgE antibody response: II. Delayed hypersensitivity and antibody production to DNP-Ascaris conjugates

Rats of the W/F strain were immunized with DNP-Ascaris conjugates using complete Freund's adjuvant (CFA), Al(OH)₃ gel (alum), or B. pertussis vaccine as adjuvants. Cell-mediated immunity was assessed by lymphotoxin in vitro and by delayed hypersensitivity in vivo. IgE and IgG antibody determinations were made on serum pools obtained at various times during the primary and secondary responses. Although delayed hypersensitivity appeared earlier than lymphotoxin, these two parameters correlated during the primary but not during the secondary response. The discrepancies suggested that different cells may be responsible for these two phenomena. Antibody production was influenced by the adjuvant used. CFA led to IgG antibody responses to both hapten and carrier but not to IgE antibody production. The use of B. pertussis resulted in both IgE and IgG antibody production. In the case of alum, anti-hapten antibodies appeared during the primary response while anti-carrier antibodies of both IgE and IgG classes were detected after booster. The results indicated that cell-mediated immunity, IgE, and IgG antibodies appeared independently in an ordered, temporal sequence, and that these responses were not mutually exclusive but were under strong modulatory influences of the various adjuvants used.     

Generation and evaluation of anti-mouse IgG IgY as secondary antibody

Abstract

In order to evaluate the possibility of using IgY as the secondary antibody in immunoassay, specific IgY (1: 128,000) was generated by immunizing hens with mouse serum IgG purified by protein A column. IgY was extracted from egg yolk by polyethylene glycol 6000 (PEG-6000), and further purified using protein M affinity chromatography column. The purified IgY was conjugated with horseradish peroxidase (HRP) and fluorescein?isothiocyanate (FITC), in that order. The reactivity of conjugated antibodies was evaluated by ELISA, Western blot and Immunofluorescence, demonstrating that the obtained IgY was able to conjugate with enzymes, react with mouse primary IgG antibody, and subsequently amplify the antigen-antibody signals in different immune reaction conditions, in a comparable secondary effect to conventional goat anti-mouse IgG antibody. The obtained conjugated antibodies showed high stability in broad pH ranges (4–10; >70%) and high thermostability at 37?°C for 84?h (>85%). Despite the need to further consider and evaluate the industrial standardization and production process, our data provided the primary evidence that conjugated IgY antibodies can be used as a secondary antibody for broad immunological analysis.     

Epidermal ridge formation in the human fetus: a correlation to the appearance of basal cell heterogeneity and the expression of epidermal growth factor receptor and cytokeratin polypeptides in the epidermis.

This paper aims to clarify an expression of epidermal growth factor receptor (EGFR) and cytokeratin 10 and/or 11 in relation to primary and secondary epidermal ridge formation of the human fetus. Firstly, scanning electron microscopy revealed heterogeneity in basal cell morphology during epidermal ridge formation. Basal cells had a uniform, smooth, and polygonal dermal surface until formation of the primary epidermal ridges. Thereafter, the dermal surface became ruffled and elliptic except at the primary epidermal ridges. Secondly, EGFR was detected by monoclonal antibody and autoradiography using 125I-EGF. The antibody reacted with primary epidermal ridge, stratum basale, stratum intermedium, and outer layer of sweat duct. The reactivity became stronger at the primary epidermal ridge than at the secondary one. The binding of 125I-EGF was concentrated in the primary epidermal ridge and sweat duct. Thirdly, cytokeratin 10 and/or 11, a maturation marker of keratinocytes, was detected by monoclonal antibody. The antibody reacted only with the stratum intermedium before secondary epidermal ridge formation. Afterward, it also reacted with the stratum basale of the secondary epidermal ridge but never reacted with that of primary epidermal ridge. The results indicate that basal cells of the secondary epidermal ridge enter the maturation process and suggest a localization of epidermal stem cells on the primary epidermal ridges. Concerning epidermal ridge formation, we suppose that the formation of the primary epidermal ridge causes the segregation of the epidermal stem cells, and that the increased density of the basal cells between the two primary epidermal ridges brings about the change in their dermal surface shape and the formation of the secondary epidermal ridge.     

Granulomatous hypersensitivity and antibody production in response to antigens of Capillaria hepatica eggs

Soluble egg antigens of Capillaria hepatica were fractionated by gel filtration chromatography into two major protein peaks of 300,000 and 14,000 mol.wt. The unfractionated antigen and both peaks were capable of sensitizing mice to produce quantitatively larger liver granulomas upon experimental innoculation of eggs; the increase in granuloma size was related to the amount of antigen used to sensitize. The antibody response in C. hepatica infected mice was primarily directed toward the high molecular weight components. Comparison of these findings with those reported for the Schistosoma mansoni egg granuloma suggests a diversity in the mechanisms of granuloma formation among helminth parasites.     

Correlation between protective antibody response and patent infection with Hymenolepis nana in mice

Correlation between protective antibody response and patent infection with Hymenolepis nana in mice. International Journal for Parasitology16: 197–203. Mice inoculated with mouse-derived cysticercoids of Hymenolepis nana, as well as with eggs, produced IgG and IgE antibodies that were detected by double diffusion (DD) and passive cutaneous anaphylaxis (PCA), respectively. When mice inoculated with eggs (day 0) were challenged with eggs (day 66), all were resistant to the challenge (assessed by the failure of cysticercoid recovery in the intestinal tissue) and produced protective antibodies evidenced by passive transfer, as well as IgG and IgE isotypes. When mice inoculated with eggs (day 0) were treated with a highly efficacious cestocide, praziquantel on day 6 at the beginning of the lumen phase, all were also resistant to the egg challenge on day 66, however, IgE, IgG, and protective antibodies were not detected. When mice treated with praziquantel before patent infection were repeatedly challenged with high doses of eggs, some of them produced IgG and IgE antibodies. From these results, it is suggested that (1) the production of protective antibody is a secondary response after patency (which may be ascribed to eggs released from mature worms), and (2) mice initially given eggs are highly resistant to egg challenge showing that an effector mechanism of acquired resistance to egg challenge may be expressed without high titres of protective antibody, at least in the serum.     

Heterologous antigenic stimulation in induction of delayed hypersensitivity.

An influence of a delayed hypersensitive reaction to a primary antigen on the induction of delayed hypersensitivity to a second unrelated antigen was observed in guinea pigs immunized with azobenzenearsonate-N-acetyl-L-tyrosine (ABAT), and injected intradermally 3 weeks later with a mixture of ABAT and secondary antigen. Animals so treated developed delayed hypersensitivity to sheep red blood cells (SRBC) or Type II pneumococcal polysaccharide as secondary antigens, as measured by skin test reactivity and inhibition of macrophage migration, whereas ABAT unsensitized control groups did not. However, attempts to induce delayed reactivity to proteins as secondary antigens were unsuccessful. The injection of secondary antigen into a mineral oil-induced inflammatory lesion did not induce delayed hypersensitivity, suggesting that specific reactivity to ABAT is a prerequisite for heterologous induction. Possible mechanisms for the observed phenomenon, including a role for macrophages, are discussed.     

Genetic and other effects on antibody and cell mediated immune response in swine leucocyte antigen (SLA)-defined miniature pigs

Summary. Miniature pigs of eight swine leucocyte antigens (SLA) haplotypes were immunized with sheep erythrocytes (SRBC), hen egg white lysozyme (HEWL) and the synthetic peptide (T, G)-A–L to induce antibody. Bacillus Calmette Geurin (BCG) and dinitrochlorobenzene (DNCB) were used to induce cell mediated immune response (CMI). Analysis of variance by least squares was used to assess the effects of SLA haplotype, sire, dam, litter and sex of pig on the magnitude of the primary and secondary antibody response and on dermal delayed type hypersensitivity induced by purified protein derivative of tuberculin (PPD) and DNCB-induced contact hypersensitivity.
The statistical model accounted for 43.50–77.30% of the observed variability in antibody and CMI at various times after immunization or challenge. While SLA had a significant effect on both antibody and CMI to some antigens at some, but not all times, sire, dam and litter were more frequently significant and to a greater degree.
Haplotypes dd, dg and gg produced more antibody to SRBC and (T, G)-A–L while dg and gg had higher primary, but not secondary antibody response to HEWL. Delayed hypersensitivity to PPD was most marked in pigs of dd, dg and gg haplotypes while contact hypersensitivity to DNCB was expressed least in the dg and gg haplotype pigs.
Heritability estimates were high for response to (T, G)-A–L and HEWL indicating feasibility of selective breeding for these traits.     

Genetic and other effects on antibody and cell mediated immune response in swine leucocyte antigen (SLA)-defined miniature pigs

Miniature pigs of eight swine leucocyte antigens (SLA) haplotypes were immunized with sheep erythrocytes (SRBC), hen egg white lysozyme (HEWL) and the synthetic peptide (T, G)-A--L to induce antibody. Bacillus Calmette Geurin (BCG) and dinitrochlorobenzene (DNCB) were used to induce cell mediated immune response (CMI). Analysis of variance by least squares was used to assess the effects of SLA haplotype, sire, dam, litter and sex of pig on the magnitude of the primary and secondary antibody response and on dermal delayed type hypersensitivity induced by purified protein derivative of tuberculin (PPD) and DNCB-induced contact hypersensitivity. The statistical model accounted for 43.50-77.30% of the observed variability in antibody and CMI at various times after immunization or challenge. While SLA had a significant effect on both antibody and CMI to some antigens at some, but not all times, sire, dam and litter were more frequently significant and to a greater degree. Haplotypes dd, dg and gg produced more antibody to SRBC and (T, G)-A--L while dg and gg had higher primary, but not secondary antibody response to HEWL. Delayed hypersensitivity to PPD was most marked in pigs of dd, dg and gg haplotypes while contact hypersensitivity to DNCB was expressed least in the dg and gg haplotype pigs. Heritability estimates were high for response to (T, G)-A--L and HEWL indicating feasibility of selective breeding for these traits.     

Fibroblast stimulation in schistosomiasis. IV. Isolated egg granulomas elaborate a fibroblast chemoattractant in vitro

Hepatic fibrosis complicates the chronic granulomatous inflammatory reaction to Schistosoma mansoni eggs, and is the major cause of morbidity and mortality in human schistosomiasis. We previously presented evidence that schistosomal egg granulomas secreted factors that can stimulate fibroblast proliferation and collagen synthesis in vitro. We now report that serum-free supernatants from cultures of hepatic egg granulomas isolated from S. mansoni-infected mice contained activity that stimulated the directional migration of human and guinea pig dermal fibroblasts in modified Boyden chambers. This fibroblast chemotactic activity was also detected in culture supernatants of granuloma adherent cells highly enriched for macrophages (95% latex-ingesting) but not in culture supernatants from resident peritoneal macrophages of uninfected or infected mice. This suggests that granuloma macrophages are a source of the chemotactic activity. The chemoattractant had the properties of large molecular weight (greater than 200,000 daltons; Sephadex G-200 gel filtration), pl approximately 4.5 (preparative flatbed isoelectrofocusing in granular matrix), heat stability (56 degrees C; 45 min), and trypsin sensitivity. Since preincubation of the partially purified granuloma and adherent-cell derived chemoattractants with rabbit anti-human fibronectin antibody abolished their chemotactic activity, it appears that the factor is antigenically similar to fibronectin. We propose that egg granuloma macrophages are activated in vivo to secrete a fibronectin-like molecule with activity that stimulates the directional migration of fibroblasts. This factor may therefore play a role in the local recruitment of fibroblasts and, in concert with other granuloma-derived factors, may play an important role in the pathogenesis of hepatic fibrosis in schistosomiasis.     

Immune response to chemically modified flagellin. IV. Further studies on the relationship between humoral and cell-mediated immunity

Acetoacetylation converts flagellin from an antigen which preferentially induces humoral antibodies to an antigen which exclusively provokes cell-mediated immunity and, under certain circumstances, induces antibody tolerance. Studies reported in this paper revealed that the acetoacetylated flagellins expressed similar immunological properties in flagellin primed rats as in normal rats. Thus, on the one hand, acetoacetylation destroyed the capacity of flagellin to trigger a secondary antibody response, but on the other hand, the acetoacetyl-flagellins very effectively induced delayed-type hypersensitivity reactions in flagellin primed animals. It was concluded from these results that humoral and cell-mediated immunity may be opposing immunological processes in both unprimed and primed animals.Acetoacetylated flagellin induced antibody tolerance in both strain W (low responder) and J (high responder) Wistar rats. Maximum tolerance was induced 12 hr after injection of antigen, but in strain J animals the tolerance had disappeared by 48 hr, whereas in strain W rats tolerance persisted for >28 days. The potential to recover from tolerance in strain J rats appeared to coincide with the level of delayed hypersensitivity at the time of challenge. However, this delayed hypersensitivity disappeared when breaking of tolerance occurred. These results suggest that the T cells which participate in delayed hypersensitivity reactions may also act as “helper” cells in antibody responses. On the other hand, it was found that priming for a secondary antibody response by flagellin appeared to coincide with development of primary antibodies rather than with induction of delayed-type hypersensitivity. The relative importance of specific T and B cells in these phenomena is discussed.     

Immunity acquired by sheep from an experimental infection with haemonchus contortus

Adams D.B. and Beh K.J. 1981. Immunity acquired by sheep from an experimental infection with Haemonchus contortus. International Journal for Parasitology11: 381–386. A primary infection of sheep with a single dose of Haemonchus contortus larvae was traced by faecal egg counts until it had substantially declined after 55 weeks. These primed sheep were then given a sequence of two reinfections with the parasite. Comparison of faecal egg counts in primed sheep and in two separate groups of previously worm-free sheep showed that primary infection conferred significant immunity. This, however, was not sufficiently protective to prevent the development of further anaemia and faecal egg counts indicative of clinical haemonchosis. It is suggested that an adaptation in the host-parasite relationship which promotes the longevity of primary infection with H. contortus may also moderate the induction of acquired immunity.The titre of haemagglutinating antibody specific for H. contortus rose in serum during the course of primary infection, but the two reinfections did not stimulate a rise in titre. Titres of haemagglutinating antibody before reinfection did not correlate with subsequent faecal egg counts.     

A hapten-specific Ir gene.

When mice of different strains were immunized with a conjugate of 2-phenyloxazolone (phOx) and chicken serum albumin (CSA), the antibody response was controlled by an Ir gene (Ir-phOx). H-2 alleles d and f were associated with a high response, k and a with an intermediate response, and allele b with a low response. The effect of the Ir gene was clear-cut in anti-carrier antibodies of the primary and the secondary response when the concentrations of anti-carrier antibodies varied between 1 and 350 microgram/ml. Anti-hapten antibodies reached a ceiling of ca. 1000 microgram/ml that was unaffected by the Ir gene. Before the ceiling was reached, antihapten antibodies were also subject to the control of the Ir-phOx gene. When the same carrier CSA was coupled with other haptens, BOC-ABA-Tyr or NO2phOx, antibody responses were not under the control of the Ir-phOx gene. This gene is probably responsible for the differences that have been observed earlier in delayed hypersensitivity and antibody responses to skin painting by phOx.     

Immunological studies on a yeast peptido-galactomannan. Nature of antigenic determinants reacting with rabbit antisera and those involved delayed hypersensitivity in guinea pigs.

The antigenicity of the peptido-phosphogalactomannan (PPGM) of Cladosporium werneckii and the carbohydrate and peptide moieties isolated from it were studied in rabbits and guinea pigs. In rabbits, the antisera produced against whole C. werneckii cells reacted only with the carbohydrate portions of the antigen. The major portion of the antibody was directed towards the long phosphogalactomannan carbohydrate chains. O-Acetyl substituents were shown to play important roles in the determinants on these chains since selective removal of these groups eliminated their reactivity with antibody. A relatively small amount of the antibody response was directed towards the more numerous, short, mannose-containing chains. Concanavalin A, on the other hand, precipitated the polymer by virture of its reactivity with these units and not with the phosphogalactomannan chains.Delayed type (cell-mediated) immunity to C. werneckii was studied in guinea pigs. PPGM was able to elicit strong delayed skin-tests as was a peptide-rich fraction derived from PPGM by mild acid hydrolysis. Pure carbohydrate chains of PPGM were completely inactive. In contrast, two of the modified peptides derived from PPGM were able to elicit a response although they were less active than PPGM. It was concluded that the determinants responsible for delayed hypersensitivity reside in the peptide portion of the antigen but that the technique used to isolate the peptides (alkaline β-elimination) partially destroyed the determinants.     

Immunolocalization of 8-5′ and 8-8′ linked structures of lignin in cell walls of Chamaecyparis obtusa using monoclonal antibodies

Mouse monoclonal antibodies were generated against dehydrodiconiferyl alcohol- or pinoresinol-p-aminohippuric acid (pAHA)-bovine serum albumin (BSA) conjugate as probes that specifically react with 8-5′ or 8-8′ linked structure of lignin in plant cell walls. Hybridoma clones were selected that produced antibodies that positively reacted with dehydrodiconiferyl alcohol- or pinoresinol-pAHA–BSA and negatively reacted with pAHA–BSA and guaiacylglycerol-beta-guaiacyl ether-pAHA–BSA conjugates containing 8-O-4′ linkage. Eight clones were established for each antigen and one of each clone that positively reacted with wood sections was selected. The specificity of these antibodies was examined by competitive ELISA tests using various lignin dimers with different linkages. The anti-dehydrodiconiferyl alcohol antibody reacted specifically with dehydrodiconiferyl alcohol and did not react with other model compounds containing 8-O-4′, 8-8′, or 5-5′ linkages. The anti-pinoresinol antibody reacted specifically with pinoresinol and syringaresinol and did not react with the other model compounds containing 8-O-4′, 8-5′, or 5-5′ linkages. The antibodies also did not react with dehydrodiconiferyl alcohol acetate or pinoresinol acetate, indicating that the presence of free phenolic or aliphatic hydroxyl group was an important factor in their reactivity. In sections of Japanese cypress (Chamaecyparis obtusa), labeling by the anti-dehydrodiconiferyl alcohol antibody was found in the secondary walls of phloem fibers and in the compound middle lamellae, and secondary walls of tracheids. Weak labeling by the anti-pinoresinol antibody was found in secondary walls of phloem fibers and secondary walls and compound middle lamellae of developed tracheids. These labelings show the localization of 8-5′ and 8-8′ linked structure of lignin in the cell walls.     

Transfer of Maternal Antibodies against Avian Influenza Virus in Mallards (Anas platyrhynchos)

Maternal antibodies protect chicks from infection with pathogens early in life and may impact pathogen dynamics due to the alteration of the proportion of susceptible individuals in a population. We investigated the transfer of maternal antibodies against avian influenza virus (AIV) in a key AIV host species, the mallard (Anas platyrhynchos). Combining observations in both the field and in mallards kept in captivity, we connected maternal AIV antibody concentrations in eggs to (i) female body condition, (ii) female AIV antibody concentration, (iii) egg laying order, (iv) egg size and (v) embryo sex. We applied maternity analysis to the eggs collected in the field to account for intraspecific nest parasitism, which is reportedly high in Anseriformes, detecting parasitic eggs in one out of eight clutches. AIV antibody prevalence in free-living and captive females was respectively 48% and 56%, with 43% and 24% of the eggs receiving these antibodies maternally. In both field and captive study, maternal AIV antibody concentrations in egg yolk correlated positively with circulating AIV antibody concentrations in females. In the captive study, yolk AIV antibody concentrations correlated positively with egg laying order. Female body mass and egg size from the field and captive study, and embryos sex from the field study were not associated with maternal AIV antibody concentrations in eggs. Our study indicates that maternal AIV antibody transfer may potentially play an important role in shaping AIV infection dynamics in mallards.     

Adoptive suppression of granuloma formation by T lymphocytes and by lymphoid cells sensitive to cyclophosphamide.

Egg-induced granulomas formed in mice with chronic Schistosoma mansoni infection are smaller than those which develop during early (8-week) infection. Adoptive transfer of spleen cells from chronically infected mice (15–25 week), which displayed modulated granulomas, to 6-week-infected recipients effectively suppressed active granuloma formation in the recipients by 8 weeks after infection. Pretreatment of these suppressive spleen cells with anti-Thy 1.2 serum and complement eliminated their suppressive capacity. Administration of cyclophosphamide (CY) (20 mg/kg, 3 times/week for 3 weeks) to 12- to 15-week-infected mice reversed modulation of granuloma formation resulting in larger granulomas at 15 weeks. This abrogation of suppression was reflected in the spleens of the CY-treated mice, as seen by the inability of their spleen cells to adoptively transfer suppression to 6-week-infected mice. This regimen of CY treatment did not significantly alter anti-schistosome egg antigen hemagglutinating antibody titers. It is reasoned that the modulation of granuloma formation observed during chronic schistosomiasis mansoni is in part dependent upon a T lymphocyte and a CY-sensitive spleen cell.     

Nonlabeled secondary antibodies augment/maintain the binding of primary, specific antibodies to cell membrane antigens.

BACKGROUND: In studies on surface membrane antigen expression using immunofluorescence techniques, it is commonly observed that direct staining gives weaker signals than the signals following indirect staining with fluorochrome-conjugated secondary antibodies. This is most marked when cells have also been permeabilized in order to stain intracellular protein. The commonly accepted explanation for this observation is that fluorochrome-conjugated secondary antibodies bind to a higher number of binding sites on the primary antibody, as compared to the binding of conjugated primary antibodies to the membrane antigens. Another hypothesis might be that the antibody/antibody complexes formed on the membranes when using the indirect technique may have an augmented ability to bind the membrane epitopes. The present study was performed in order to check this hypothesis. MATERIALS AND METHODS: Peripheral blood mononuclear cells were stained with fluorochrome-conjugated anti-CD antibodies directly without or with a second-step application of nonconjugated goat anti-mouse IgG antibodies, followed by different fixation and permeabilization methods. The cells were analyzed by flow cytometry. RESULTS: A second-step application of nonconjugated goat anti-mouse IgG antibodies following direct staining with fluorochrome-conjugated anti-CD antibodies gave a significant increase in membrane antigen expression on permeabilized cells as compared to direct staining alone. The secondary antibody must be bivalent, since whole IgG or F(ab')(2) fragments of the goat anti-mouse antibodies showed effects, while Fab fragments did not. CONCLUSIONS: Nonlabeled secondary antibodies are able to influence the binding of primary, specific antibodies to cell membrane antigens on cells treated with permeabilizing agents necessary for staining intracellular proteins. The improved membrane antigen expression seems to be due to the formation of a network of primary and secondary antibodies on the cell surface, with increased ability for maintaining binding to CD antigens.     

Patterns of Reactivity between a Panel of Monoclonal Antibodies and Forage Rhizobium Strains

A panel of 11 monoclonal antibodies raised against vegetative cells of Rhizobium leguminosarum biovar trifolii or Rhizobium meliloti was tested by enzyme-linked immunosorbent assay for reactivity with 47 strains of R. leguminosarum biovar trifolii and 60 strains of R. meliloti. The goal of the study was to define the degree of specificity associated with each antibody and to gain an understanding of the amount of antigenic diversity found among the strains and between the species. Each antibody was tested against each Rhizobium strain in four forms: washed steamed cells, washed unsteamed cells, cell-free culture broth, and nodule squash material. Each antibody showed a different pattern of reactivity among the 107 strains. One of each of the antibodies developed against R. meliloti and R. leguminosarum biovar trifolii reacted in a highly specific manner with cells or antigen from the immunogenic strain only. Nine of the antibodies recognized secreted as well as cellular antigen from many of the strains. Analysis of patterns of reactivity between the 107 strains and the 11 antibodies separated the strains into 28 groups of which 12 were represented by one strain only.     

Carrier-induced tolerance to nucleic acid antigens.

BALB/c and SJL mice were treated with nucleosides-IgG1 as a tolerogen, before either primary or secondary immunization with nucleosides-keyhole limpet hemocyanin. Nucleoside-specific responses were measured serologically by a modified Farr assay, with either 14C-labeled denatured DNA or nucleosides-131-I-labeled BSA as test antigen. Specificity of the response was tested by hapten inhition experiments. Multiple doses of nucleosides-IgG1 tolerogen given before the primary or secondary immunization effectively suppressed the secondary and tertiary anti-nucleoside responses. The tolerogen did not suppress the response to an unrelated hapten-KLH conjugate. The IgG alone did not suppress the anti-nucleoside response of BALB/c mice to nucleosides-KLH. Single doses of tolerogen before the primary or secondary immunization were less effective. Residual antibody in partially suppressed BALB/c mice showed changes in specificity as compared to controls. Suppression of the secondary response of SJL mice was measured much more readily by binding of nucleosides-131-I-BSA than by binding of denatured DNA. This reflected an altered specificity of the residual antibody; in control animals, antibodies were directed against all four nucleosides, whereas the antibodies of partially suppressed animals were directed only against guanosine. Suppression of anti-nucleic acid antibody responses may have therapeutic application in the management of systemic lupus erythematosus.