Immunoglobulin-secreting cells of maternal origin can be detected in B cell-deficient mice

It is well known that the transfer of immunoglobulins (Igs) from mother to young via milk contributes to the offspring's immune defense. The present study suggests that not only is IgG transmitted to progeny, but that functional maternal Ig-secreting cells (or B cells) can also be transferred to the neonate. We have used B cell-deficient (micro(-/-)) mice and found that a high proportion of them obtain long-lasting, partial reconstitution of their serum Ig levels if born to micro(+/-) mothers. In some of these serum IgG-positive micro(-/-) mice, Ig-secreting cells were detected in spleen and bone marrow. To ensure that cells of maternal origin were present in the progeny, micro(-/-) offspring born to micro(+/-) dams transgenic for green fluorescent protein (GFP) were used. In spleens and bone marrow from some of these micro(-/-)GFP(-/-) offspring, GFP-positive cells were detected, which demonstrated that cells of maternal origin could infiltrate the progeny. In addition, splenic Ig-secreting cells were detected in micro(-/-) mice that were born to micro(-/-) dams and transferred to a lactating micro(+/+) foster dam at birth. This indicates that maternal Ig-secreting cells can be transferred postnatally via milk.     

Lymphocyte development and function in the absence of retinoic acid-related orphan receptor alpha

The orphan nuclear receptor, retinoid acid-related orphan receptor (ROR)alpha, is essential for the development of cerebellar Purkinje cells and bone tissue. RORalpha may also play a critical role in lymphocyte development and function because staggerer mice, a natural mutant strain with a disrupted expression of RORalpha, have reduced thymic and splenic cellularity. In this report, we analyzed the role of RORalpha in lymphocyte development by examining lymphoid compartments in RORalpha(-/-) mice and Rag-2(-/-) mice reconstituted with RORalpha(-/-) bone marrow. We found that T and B cell development was severely defective in RORalpha(-/-) mice, but not in Rag-2(-/-)/RORalpha(-/-) chimeric mice. We also analyzed cellular and humoral immune responses in Rag-2(-/-)/RORalpha(-/-) chimeric mice. Our results show that serum IgG levels were elevated in Rag-2(-/-)/RORalpha(-/-) chimeric mice after immunization with a T-dependent Ag compared with control chimeras. IFN-gamma production by RORalpha(-/-) CD8(+) T cells after TCR stimulation was also increased. Furthermore, RORalpha(-/-) mast cells and macrophages produced an increased amount of TNF-alpha and IL-6 upon activation. These results indicate that RORalpha indirectly regulates lymphocyte development by providing an appropriate microenvironment and controls immune responses by negatively regulating cytokine production in innate immune cells and lymphocytes.     

Cell-mediated immune responses to Chlamydia trachomatis in mothers and infants

Cell-mediated immunity to Chlamydia trachomatis was studied in pregnant women with chlamydial infection of the cervix, in infants born vaginally to these women, and in infants presenting with chlamydial conjunctivitis. Uninfected pregnant women and their infants were studied as controls. McCoy cell cultures were used to isolate C. trachomatis from clinical specimens. Cell-mediated immunity was measured by lymphocyte proliferative responses in vitro to stimulation by chlamydial antigens. Chlamydial IgG antibody in serum specimens was detected by a microenzyme-linked immunosorbent assay technique. The mean lymphocyte proliferative responses to chlamydial antigens were greater in infected women than in uninfected women both during pregnancy and in the postpartum period. Lymphocyte responsiveness in infected pregnant women, however, was less than in postpartum women. Despite failure to detect chlamydial infection in exposed infants, lymphocyte proliferative responses were greater in umbilical cord blood and later in peripheral blood samples from neonates born to infected mothers than in infants born to uninfected mothers. These responses were also greater in infants with chlamydial conjunctivitis than in infants of uninfected mothers. These data suggest that cellular immune responses to chlamydial antigens are increased in infected mothers and infants and that infants may acquire chlamydial cell-mediated immunity transplacentally.     

Protective effect of colostrum in Mycoplasma pneumoniae infection induced in infant mice

The immunological responses and mechanism of maternal immunity in Mycoplasma pneumoniae infection of mice were investigated. ICR female mice, 4 weeks old, and infant mice, 2 to 4 days old, were infected with M. pneumoniae. Anti-M. pneumoniae antibodies in serum and colostrum were determined by enzyme-linked immunosorbent assay. The specific IgG antibody production persisted for 9 months or longer in both the young and infant mice. These infected mice were protected from rechallenge with M. pneumoniae. In addition, the infected dams conferred passive immunity on their offspring. The infant mice born to uninfected normal dams were protected from the challenge with M. pneumoniae when fed by infected foster dams. Conversely, the infant mice born to infected dams were not protected from the challenge with M. pneumoniae when the infants were fed by uninfected dams. The specific IgG antibody appeared in serum of infant mice inoculated orally with M. pneumoniae-infected mouse serum and the infants were protected from challenge with M. pneumoniae, while the infants given protein A-absorbed serum were not protected from the challenge. These results suggest that one of the factors involved in the resistance of infant mice to M. pneumoniae infection is the specific IgG antibody present in the colostrum rather than the result of transplacental transfer.     

Maternal immunization with pneumococcal surface protein A protects against pneumococcal infections among derived offspring

Pathogen-specific antibody plays an important role in protection against pneumococcal carriage and infections. However, neonates and infants exhibit impaired innate and adaptive immune responses, which result in their high susceptibility to pneumococci. To protect neonates and infants against pneumococcal infection it is important to elicit specific protective immune responses at very young ages. In this study, we investigated the protective immunity against pneumococcal carriage, pneumonia, and sepsis induced by maternal immunization with pneumococcal surface protein A (PspA). Mother mice were intranasally immunized with recombinant PspA (rPspA) and cholera toxin B subunit (CTB) prior to being mated. Anti-PspA specific IgG, predominantly IgG1, was present at a high level in the serum and milk of immunized mothers and in the sera of their pups. The pneumococcal densities in washed nasal tissues and in lung homogenate were significantly reduced in pups delivered from and/or breast-fed by PspA-immunized mothers. Survival after fatal systemic infections with various types of pneumococci was significantly extended in the pups, which had received anti-PspA antibody via the placenta or through their milk. The current findings strongly suggest that maternal immunization with PspA is an attractive strategy against pneumococcal infections during early childhood.     

Elicitation of antigen-induced primary and secondary murine IgE antibody responses in vitro

Described herein are methods for eliciting and quantitating primary and secondary murine IgE antibody responses in vitro, and the important role of antigen concentration in determining the level of IgE produced during an immune response. The methods for quantitating IgE antibody levels in culture supernatant fluids and in serum by ELISA are presented in detail. The specificity of such methods was confirmed in that (1) no other isotype of antibody registered in the IgE-ELISA, and (2) parallel determinations of IgE antibody concentrations could be obtained by independent analysis using Fc epsilon RI-dependent basophil degranulation. We examined various parameters of cell donor immunization and lymphoid cell culture which allow for optimal in vitro primary and secondary IgE responses. High relative antigen doses result in diminished IgE antibody responses in experimental animals, a finding confirmed herein. High antigen concentrations in vitro also result in relative suppression of IgE antibody synthesis. This was also true for in vitro production of IgG1 and IgA antibodies. Conversely, IgM and IgG2a responses were elicited at both low and high antigen concentrations; IgG2b and IgG3 were not produced under the conditions of priming and culture used herein. Finally, production of IgE in vitro depended on the presence of carrier-primed CD4+ T cells and hapten-specific B cells. Generation of maximal IgE antibody secretion, and hence elicitation of an allergic reaction, is thus dependent on the amount of antigen acting as stimulant for the immune response.     

Neonatal immunization with a Sindbis virus-DNA measles vaccine induces adult-like neutralizing antibodies and cell-mediated immunity in the presence of maternal antibodies

Infants younger than age 9 mo do not respond reliably to the live attenuated measles vaccine due the immaturity of their immune system and the presence of maternal Abs that interfere with successful immunization. We evaluated the immune responses elicited by Sindbis virus replicon-based DNA vaccines encoding measles virus (MV) hemagglutinin (H, pMSIN-H) or both hemagglutinin and fusion (F, pMSINH-FdU) glycoproteins in neonatal mice born to naive and measles-immune mothers. Despite the presence of high levels of maternal Abs, neonatal immunization with pMSIN-H induced long-lasting, high-avidity MV plaque reduction neutralization (PRN) Abs, mainly IgG2a, that also inhibited syncytium formation in CD150(+) B95-8 cells. IgG secreting plasma cells were detected in spleen and bone marrow. Newborns vaccinated with pMSINH-FdU elicited PRN titers that surpassed the protective level (200 mIU/ml) but were short-lived, had low syncytium inhibition capacity, and lacked avidity maturation. This vaccine failed to induce significant PRN titers in the presence of placentally transferred Abs. Both pMSIN-H and pMSINH-FdU elicited strong Th1 type cell-mediated immunity, measured by T cell proliferation and IFN-gamma production, that was unaffected by maternal Abs. Newborns responded to measles DNA vaccines with similar or even higher PRN titers and cell-mediated immunity than adult mice. This study is the first demonstration that a Sindbis virus-based measles DNA vaccine can elicit robust MV immunity in neonates bypassing maternal Abs. Such a vaccine could be followed by the current live attenuated MV vaccine in a heterologous prime-boost to protect against measles early in life.     

DNA vaccines for influenza virus: differential effects of maternal antibody on immune responses to hemagglutinin and nucleoprotein

Maternal antibody is the major form of protection from disease in early life when the neonatal immune system is still immature; however, the presence of maternal antibody also interferes with active immunization, placing infants at risk for severe bacterial and viral infection. We tested the ability of intramuscular and gene gun immunization with DNA expressing influenza virus hemagglutinin (HA) and nucleoprotein (NP) to raise protective humoral and cellular responses in the presence or absence of maternal antibody. Neonatal mice born to influenza virus-immune mothers raised full antibody responses to NP but failed to generate antibody responses to HA. In contrast, the presence of maternal antibody did not affect the generation of long-lived CD8(+) T-cell responses to both HA and NP. Thus, maternal antibody did not affect cell-mediated responses but did affect humoral responses, with the ability to limit the antibody response correlating with whether the DNA-expressed immunogen was localized in the plasma membrane or within the cell.     

Lymphocytes lacking I kappa B-alpha develop normally, but have selective defects in proliferation and function

NF-kappaB has been implicated in the development, activation, and function of B and T lymphocytes. We have evaluated the in vivo effects of deletion of IkappaB-alpha, a major inhibitor of NF-kappaB, on lymphocyte development, proliferation, and function. To elucidate the long term role of IkappaB-alpha in lymphocytes, fetal liver cells of 14.5-day-old IkappaB-alpha(-/-) or wild-type embryos were transplanted into irradiated recombinase-activating gene-2-deficient mice. Within 4 wk, the IkappaB-alpha(-/-) fetal liver cells reconstitute mature B and T cell populations in the recipients comparable to those produced by wild-type fetal liver cells. However, the proliferative responses of IkappaB-alpha(-/-) B cells are enhanced, whereas those of IkappaB-alpha(-/-) T cells are reduced. The levels of IgG1, IgG2a, IgA, and IgE produced by IkappaB-alpha(-/-) B cells are elevated relative to those produced by IkappaB-alpha(+/+) or IkappaB-alpha(+/-). Moreover, the specific immune responses to OVA and the generation of germinal centers are impaired in recipients of IkappaB-alpha(-/-) fetal liver cells. These results indicate that IkappaB-alpha plays a vital role in signal transduction pathways regulating lymphocyte proliferation and also in the production of specific Ig isotypes.     

Humoral immunity in malnutrition

Malnutrition affects the humoral immune system in diverse fashions. B lymphocyte subpopulations, serum IgG, and IgA levels, and immunoglobulin synthesis and metabolism are usually normal or increased. Hypogammaglobulinemia may occur in very young, severely malnourished infant. Although usually normal, deficient antibody responses to injected antigens are occasionally present, depending on the severity of the malnutrition. Serum IgE levels are usually high in malnutrition, probably due both to the increased incidence of intestinal parasites and to the lack of T cell control of IgE. Despite these high IgE levels, allergy is unusual. Secretory IgA levels in the respiratory and gastrointestinal (GI) fluids are generally decreased, as are secretory IgA antibody responses. This local antibody deficiency may increase GI permeability, stimulate immune complex formation, and result in the formation of IgG food antibodies. Breast milk secretory IgA levels are equivalent in malnourished mothers but because of lessened milk volume, the total amount of secretory IgA delivered to their offspring is diminished. Complement levels are somewhat diminished in the presence of malnutrition with a resultant opsonic deficiency. Although these B cell system aberrations undoubtedly contribute to the enhanced susceptibility to infection of malnourished patients, they are usually less severe than are concomitant T cell deficiencies.     

NF-kappa B is required within the innate immune system to inhibit microflora-induced colitis and expression of IL-12 p40

We have previously presented evidence demonstrating that mice deficient in NF-kappaB subunits are susceptible to colitis induced by the pathogenic enterohepatic Helicobacter species, H. hepaticus. However, it has not been determined whether NF-kappaB is required within inhibitory lymphocyte populations, within cells of the innate immune system, or both, to suppress inflammation. To examine these issues, we have performed a series of adoptive transfer experiments using recombination-activating gene (Rag)-2(-/-) or p50(-/-)p65(+/-)Rag-2(-/-) mice as hosts for wild-type (WT) and p50(-/-)p65(+/-) lymphocyte populations. We have shown that although the ability of H. hepaticus to induce colitis in Rag-2(-/-) mice is inhibited by the presence of either WT or p50(-/-)p65(+/-) splenocytes, these splenocyte populations are unable to suppress H. hepaticus-induced colitis in p50(-/-)p65(+/-)Rag-2(-/-) mice. Colitis in these animals is characterized by increased expression of inflammatory cytokines including IL-12 p40, and depletion of IL-12 p40 from p50(-/-)p65(+/-) mice ameliorates H. hepaticus-induced disease. Consistent with a primary defect in the regulation of IL-12 expression, H. hepaticus induced markedly higher levels of IL-12 p40 in p50(-/-)p65(+/-) macrophages than in WT macrophages. These results suggest that inhibition of H. hepaticus-induced IL-12 p40 expression by NF-kappaB subunits is critical to preventing colonic inflammation in response to inflammatory microflora.     

Successful induction of CD8 T cell-dependent protection against malaria by sequential immunization with DNA and recombinant poxvirus of neonatal mice born to immune mothers

In some parts of Africa, 50% of deaths attributed to malaria occur in infants less than 8 mo. Thus, immunization against malaria may have to begin in the neonatal period, when neonates have maternally acquired Abs against malaria parasite proteins. Many malaria vaccines in development rely upon CD8 cells as immune effectors. Some studies indicate that neonates do not mount optimal CD8 cell responses. We report that BALB/c mice first immunized as neonates (7 days) with a Plasmodium yoelii circumsporozoite protein (PyCSP) DNA vaccine mixed with a plasmid expressing murine GM-CSF (DG) and boosted at 28 days with poxvirus expressing PyCSP were protected (93%) as well as mice immunized entirely as adults (70%). Protection was dependent on CD8 cells, and mice had excellent anti-PyCSP IFN-gamma and cytotoxic T lymphocyte responses. Mice born of mothers previously exposed to P. yoelii parasites or immunized with the vaccine were protected and had excellent T cell responses. These data support assessment of this immunization strategy in neonates/young infants in areas in which malaria exacts its greatest toll.     

Brugia pahangi: effects of maternal filariasis on the responses of their progeny to homologous challenge infection.

Granulomatous lesion formation and immune responses to Brugia pahangi infections were compared in age-matched male progeny of homologously infected and uninfected female jirds. Infections initiated in 2-week-old offspring yielded mean +/- SD adult worm recoveries of 6.0 +/- 5.7 and 4.2 +/- 5.4 in offspring from infected or uninfected mothers, respectively. Infections initiated in 4-week-old offspring resulted in an mean +/- SD recovery of adult worms of 11.3 +/- 11.3 and 10.2 +/- 5.8 in offspring from infected and uninfected mothers, respectively. The ratio of intralymphatic thrombi per intralymphatic worm was similar between infected offspring from infected or uninfected mothers within experiments. Areas of granulomas around B. pahangi antigen-coated beads embolized in the lungs were not significantly affected by maternal origin in infected or uninfected progeny. Offspring infected at 2 or 4 weeks of age from infected mothers exhibited significantly reduced titers of serum IgG antibodies to Brugia antigens at 5-8 weeks postinfection compared to infected offspring of uninfected mothers. Infected offspring from infected mothers also had significantly fewer splenic IgG plaque-forming cells to B. pahangi antigens at 5 weeks postinfection than similarly infected offspring from uninfected mothers. Western immunoblot analysis indicated qualitative and quantitative reductions in serum antibody reactivity to adult B. pahangi antigens in infected progeny of infected females compared to age-matched infected controls. Reduced homologous serum antibody responses in progeny exposed to maternal B. pahangi infection suggest that maternal immunoregulation to filarial antigens may occur. Reduced antibody responsiveness to B. pahangi antigens observed in infected offspring from infected mothers, however, had no demonstrable effect on adult worm burdens, microfilaremias, lymphatic lesion formation, or antigen-specific granulomatous inflammatory responses compared to infected progeny of uninfected mothers.     

Maternal LAMP/p55gagHIV-1 DNA immunization induces in utero priming and a long-lasting immune response in vaccinated neonates

Infants born to HIV-infected mothers are at high risk of becoming infected during gestation or the breastfeeding period. A search is thus warranted for vaccine formulations that will prevent mother-to-child HIV transmission. The LAMP/gag DNA chimeric vaccine encodes the HIV-1 p55gag fused to the lysosome-associated membrane protein-1 (LAMP-1) and has been shown to enhance anti-Gag antibody (Ab) and cellular immune responses in adult and neonatal mice; such a vaccine represents a new concept in antigen presentation. In this study, we evaluated the effect of LAMP/gag DNA immunization on neonates either before conception or during pregnancy. LAMP/gag immunization of BALB/c mice before conception by the intradermal route led to the transfer of anti-Gag IgG1 Ab through the placenta and via breastfeeding. Furthermore, there were an increased percentage of CD4+CD25+Foxp3+T cells in the spleens of neonates. When offspring were immunized with LAMP/gag DNA, the anti-Gag Ab response and the Gag-specific IFN-γ-secreting cells were decreased. Inhibition of anti-Gag Ab production and cellular responses were not observed six months after immunization, indicating that maternal immunization did not interfere with the long-lasting memory response in offspring. Injection of purified IgG in conjunction with LAMP/gag DNA immunization decreased humoral and cytotoxic T-cell responses. LAMP/gag DNA immunization by intradermal injection prior to conception promoted the transfer of Ab, leading to a diminished response to Gag without interfering with the development of anti-Gag T- and B-cell memory. Finally, we assessed responses after one intravenous injection of LAMP/gag DNA during the last five days of pregnancy. The intravenous injection led to in utero immunization. In conclusion, DNA vaccine enconding LAMP-1 with Gag and other HIV-1 antigens should be considered in the development of a protective vaccine for the maternal/fetal and newborn periods.     

Adjuvant costimulation during secondary antigen challenge directs qualitative aspects of oral tolerance induction, particularly during the neonatal period

In this report we demonstrate that although passive feeding of specific Ag to mice as neonates or adults can induce oral tolerance in both the cellular and humoral arms of the immune response, quantitative and, in particular, qualitative aspects of the tolerance process are determined by the nature of the inflammatory costimuli provided at the time of secondary Ag challenge. Moreover, this dependency upon nonspecific costimulation is more profound in Ag-fed neonates than in their adult counterparts. Thus, administration of Ag in the Th1-selective adjuvant CFA to prefed animals resulted in significant inhibition of IgG2a, IL-2, and IFN-gamma responses, whereas IL-5 responses were increased. In contrast, rechallenge with Ag in the Th2-selective adjuvant aluminum hydroxide resulted in significant inhibition of IgG1, IgE, IL-2, and IL-5 responses, whereas IFN-gamma responses were increased. Additionally, although soluble Ag challenge of prefed adults revealed marginal tolerogenic effects, the same challenge protocol in animals prefed as neonates elicited enhanced Th2-dependent IgG1 production. These results suggest that inflammatory stimulation at the time of Ag challenge is obligatory to trigger oral tolerance mechanisms, particularly in animals fed as neonates and also that the type of adjuvant used at the time of challenge selects for the type of Th cell population to be inhibited.     

Maternal transmission of resistance to development of allergic airway disease

Parental phenotype is known to influence the inheritance of atopic diseases, such as allergic asthma, with a maternal history being a more significant risk factor for progeny than paternal history. We hypothesized that recall Th1- or Th2-type immune responses during pregnancy would result in transfer of maternal factors that would differentially impact development of immune responsiveness in offspring. Following weaning, susceptibility and severity of allergic airway disease (a murine model of human asthma) was evaluated in progeny, disease being elicited by immunization with OVA-Al(OH)(3) and challenge with aerosolized OVA. We found that progeny of mothers with Th1-biased immunity to OVA subjected to recall aerosol challenge during pregnancy had reduced levels of Ag-specific IgE and airway eosinophilia compared with progeny of mothers with Th2-biased immunity to OVA or naive mothers. Interestingly, progeny of mothers with Th1-type immunity to a heterologous albumin, BSA, were not protected from developing OVA-induced allergic airway disease. These findings demonstrated that maternal transfer of protection from development of allergic airway disease to offspring in this model of maternal Th1-type immunity was Ag specific.     

Family studies of association between HLA and specific immune responses to highly purified pollen allergens

In 76 members of 13 large families, we investigated whether association exists between specific familialHLA haplotypes and immune responsiveness to four different highly purified pollen antigens (ragweed antigens E, Ra3, and Ra5 and rye grass Group I). Specific immune response was studied quantitatively by measurement of IgE-mediated skin sensitivity, serum IgG antibody, and antigen-induced lymphocyte proliferationin vitro. We found no evidence for association between specificHLA haplotype and specific response measured by any one or more of our indices of immune function. In several families we found evidence of specific response in one generation but not in another. We found a number of instances of individuals exhibiting lymphocyte responsiveness to an antigen, but no detectable specific IgE or IgG antibody. Surprisingly, we also found a few cases of individuals with marked IgE and/or IgG responses to a given antigen who showed no measurable lymphocyte responsiveness to that antigen, despite lymphocyte responsiveness to other nonimmunologically crossreacting antigens. In several cases, we also observed lymphocyte stimulation and serum IgG antibody, but no detectable IgE response. Our results conflict with previous investigators' reports of linkage betweenHLA haplotype and specific IgE-mediated skin sensitivity in families.HLA- linked immune response (Ir) loci may exist in humans, but genetic complexity and the limits of current technology preclude our ability to demonstrate their existence.     

Orally administered microencapsulated reovirus can bypass suckled, neutralizing maternal antibody that inhibits active immunization of neonates.

Purified reovirus serotype 1, encapsulated in biodegradable aqueous microcapsules, was found to bypass maternal antibody passively transferred by suckling to neonates. Genetically identical, immunocompetent F1 scid/+ mice were generated by the reciprocal crosses of C.B17 scid/scid and normal congenic +/+ adult mice. The immunocompetent +/+ dams were either orally infected with reovirus prior to mating or not. Thus, these immunocompetent F1 pups developed either in the absence or in presence of passively transferred maternal immunity. The F1 mice were orally immunized on day 10 with either live virus, microencapsulated reovirus, or empty microcapsules plus live virus. The immune responses were assessed in the neonatal gut-associated lymphoid tissues (GALT). Examination of reovirus specific immunoglobulin A in the serum and GALT, taken on days 7, 14, and 21 postimmunization, clearly demonstrated that microencapsulated reovirus could bypass the normal effect of maternal antibodies, passively acquired by suckling, to inhibit active priming of neonates by oral route. These observations seem relevant to the development of efficacious oral vaccines that also allow passive, protective immunity via suckled maternal antibodies while permitting active oral immunization of neonates.     

IgE Production to α-Gal Is Accompanied by Elevated Levels of Specific IgG1 Antibodies and Low Amounts of IgE to Blood Group B

IgE antibodies to gal-α-1,3-gal-β-1,4-GlcNAc (α-gal) can mediate a novel form of delayed anaphylaxis to red meat. Although IgG antibodies to α-gal (anti-α-gal or anti-Gal) are widely expressed in humans, IgE anti-α-gal is not. We explored the relationship between the IgG and IgE responses to both α-gal and the related blood group B antigen. Contradicting previous reports, antibodies to α-gal were found to be significantly less abundant in individuals with blood group B or AB. Importantly, we established a connection between IgE and IgG responses to α-gal: elevated titers of IgG anti-α-gal were found in IgE-positive subjects. In particular, proportionally more IgG1 anti-α-gal was found in IgE-positive subjects against a background of IgG2 production specific for α-gal. Thus, two types of immune response to α-gal epitopes can be distinguished: a ‘typical’ IgG2 response, presumably in response to gut bacteria, and an ‘atypical’, Th2-like response leading to IgG1 and IgE in addition to IgG2. These results suggest that IgE to a carbohydrate antigen can be formed (probably as part of a glycoprotein or glycolipid) even against a background of bacterial immune stimulation with essentially the same antigen.     

Genetic attachment of undecane peptides to ovomucoid third domain can suppress the production of specific IgG and IgE antibodies

An undecane peptide (Gly-Ser-Pro-Gly-Ile-Pro-Gly-Ser-Thr-Gly-Met) was genetically attached to the N-terminus of ovomucoid third domain (DIII) to investigate structural characteristics of linear IgE and IgG (B cell) epitopes in DIII with respect to modulation of the immune response towards antigenicity and allergenicity. Balb/c mice were sensitized with native DIII, wild type recombinant DIII, and recombinant modified DIII containing the extra amino acid stretch. The immune responses to the antigens were compared using enzyme-linked immunosorbent assay. Interestingly, specific IgE and IgG levels were suppressed when the modified DIII was used as antigen. This was further confirmed by synthesizing immunodominant IgE and IgG epitopes of DIII on cellulose acetate membrane (SPOTs) and probing them with antibodies raised against DIII antigens. Anti-recombinant wild type DIII anti-serum showed strong binding activities to immunodominant IgE and IgG epitopes, while anti-modified DIII serum did not show any significant binding to the IgE and IgG epitopes. Thus, it is clearly demonstrated that the amino acid stretch in DIII is masking the immune reactive epitope. Genetical attachment of peptides into DIII was found to be effective in reducing the production of specific IgE and IgG antibodies in mice.