Renaissance of the blocking antibody concept in type I allergy

Allergen-specific polyclonal antibodies reduce allergic disease in a mouse model of allergic asthma

BACKGROUND

Recombinant allergen-specific immunoglobulin G (IgG) antibody therapy can reduce allergic asthma symptoms by inhibiting the immunoglobulin E (IgE)-mediated allergic response. This study investigated the effect of intranasally administered allergen-specific monoclonal (mAb) and polyclonal (pAb) antibody on airway inflammation and hyperresponsiveness (AHR) in a mouse model of human asthma.

METHODS

Ovalbumin (OVA)-specific IgG2b antibodies were generated by phage display using spleens from OVA-immunized mice, and screening against OVA and finally expressed in CHO cells. Sensitized mice were treated intranasally with either a recombinant anti-OVA mAb (gc32) or a polyclonal preparation comprising seven selected antibodies (including gc32). Control mice received diluent only, OVA only, a control polymeric IgG or dexamethasone. Following challenge with nebulized OVA, investigators assessed airway inflammation by histology and cellular composition of the bronchoalveolar fluid, and methacholine-induced airway hyperresponsiveness (AHR). Serum levels of total and OVA-specific IgE were measured by ELISA.

RESULTS

Sensitized mice developed airway inflammation and AHR in response to OVA challenge. Intranasally administered OVA-specific murine polyclonal or monoclonal IgG2b antibodies both reduced OVA-induced lung inflammation. Polyclonal, but not anti-OVA mAb, also reduced AHR and eosinophil influx into the airway lumen. Both anti-OVA antibody preparations reduced levels of specific IgE with no effect on total IgE levels.

CONCLUSIONS

Intranasal treatment with allergen-specific pAb reduces pulmonary inflammation and AHR in a mouse model of allergic asthma, but allergen-specific mAb reduces inflammation only. Allergen-specific recombinant pAb offers a potentially valuable therapeutic approach to the management of allergic asthma.

IgE-Facilitated Antigen Presentation: Role in Allergy and the Influence of Allergen Immunotherapy

IgE-facilitated allergen presentation (FAP) is an important pathogenic mechanism in allergic disease and represents a potential therapeutic target. Allergen immunotherapy is a highly effective therapy, particularly in patients with seasonal pollinosis who fail to respond to usual pharmacotherapy. Allergen immunotherapy induces "blocking" IgG antibodies that are detectable in serum and have been shown to inhibit IgE-FAP in vitro. This review summarizes the main components involved in IgE-FAP and the potential value of a validated functional assay of serum inhibitory antibodies for IgE-FAP for monitoring the clinical response to immunotherapy.

IgG-blocking antibodies inhibit IgE-mediated anaphylaxis in vivo through both antigen interception and Fc gamma RIIb cross-linking

Although it has long been hypothesized that allergen immunotherapy inhibits allergy, in part, by inducing production of IgG Abs that intercept allergens before they can cross-link mast cell Fc epsilonRI-associated IgE, this blocking Ab hypothesis has never been tested in vivo. In addition, evidence that IgG-allergen interactions can induce anaphylaxis by activating macrophages through Fc gammaRIII suggested that IgG Ab might not be able to inhibit IgE-mediated anaphylaxis without inducing anaphylaxis through this alternative pathway. We have studied active and passive immunization models in mice to approach these issues and to determine whether any inhibition of anaphylaxis observed was a direct effect of allergen neutralization by IgG Ab or an indirect effect of cross-linking of Fc epsilonRI to the inhibitory IgG receptor Fc gammaRIIb. We demonstrate that IgG Ab produced during the course of an immune response or administered passively can completely suppress IgE-mediated anaphylaxis; that these IgG blocking Abs inhibit IgE-mediated anaphylaxis without inducing Fc gammaRIII-mediated anaphylaxis only when IgG Ab concentration is high and challenge allergen dose is low; that allergen epitope density correlates inversely with the allergen dose required to induce both IgE- and Fc gammaRIII-mediated anaphylaxis; and that both allergen interception and Fc gammaRIIb-dependent inhibition contribute to in vivo blocking Ab activity.

Immune mechanisms of allergen-specific sublingual immunotherapy

Sublingual immunotherapy has been shown in some clinical studies to modulate allergen-specific antibody responses [with a decrease in the immunoglobulin E/immunoglobulin G4 (IgE/IgG4) ratio] and to reduce the recruitment and activation of proinflammatory cells in target mucosa. Whereas a central paradigm for successful immunotherapy has been to reorient the pattern of allergen-specific T-cell responses in atopic patients from a T helper (Th)2 to Th1 profile, there is currently a growing interest in eliciting regulatory T cells, capable of downregulating both Th1 and Th2 responses through the production of interleukin (IL)-10 and/or transforming growth factor (TGF)-beta. We discuss herein immune mechanisms involved during allergen-specific sublingual immunotherapy (SLIT), in comparison with subcutaneous immunotherapy. During SLIT, the allergen is captured within the oral mucosa by Langerhans-like dendritic cells expressing high-affinity IgE receptors, producing IL-10 and TGF-beta, and upregulating indoleamine dioxygenase (IDO), suggesting that such cells are prone to induce tolerance. The oral mucosa contains limited number of proinflammatory cells, such as mast cells, thereby explaining the well-established safety profile of SLIT. In this context, second-generation vaccines based on recombinant allergens in a native conformation formulated with adjuvants are designed to target Langerhans-like cells in the sublingual mucosa, with the aim to induce allergen-specific regulatory T cells. Importantly, such recombinant vaccines should facilitate the identification of biological markers of SLIT efficacy in humans.

Molecular design of allergy vaccines

Recombinant-allergen-based diagnostic tests enable the dissection and monitoring of the molecular reactivity profiles of allergic patients, resulting in more specific diagnosis, disease monitoring, prevention and therapy. In vitro experiments, animal studies and clinical trials in patients demonstrate that allergenic molecules can be engineered to induce different immune responses ranging from tolerance to vigorous immunity. The available data thus suggest that molecular engineering of the disease-related antigens is a technology that may be applicable not only for the design of allergy vaccines but also for the design of vaccines against infectious diseases, autoimmunity and cancer.

Failure to protect goats following vaccination with soluble proteins of Sarcoptes scabiei: Evidence for a role for IgE antibody in protection

Developing an anti-scabies vaccine is thought to be a feasible alternative to chemical control, since animals which have recovered from sarcoptic mange become resistant against mite reinfestation. The purpose of this study was to evaluate the protective value of immune responses developed in animals after immunisation with soluble mite proteins. Soluble proteins from Sarcoptes scabiei were extracted then subjected to ion exchange chromatography, and proteins from the column were eluted step-wise with 0%, 10%, 25% and 50% of 1 M solution of NaCl in a Tris buffer. Each protein fraction was concentrated and dialysed against PBS. To evaluate the immunogenicity of the fractions, 36 goats were allocated into six groups, group1 goats were unvaccinated, group 2 were vaccinated with intact soluble mite proteins, and groups 3-6 were vaccinated respectively with the fractionated proteins. Vaccinations were conducted four times with 1 mg protein/dose and 4-week intervals between vaccinations. One week after the last vaccination, all goats were challenged with approximately 2000 live mites on the auricles and infestations were allowed to progress for 6 weeks. The severity of lesions caused by the infestation was assessed throughout the study. The challenge caused mange or encrustation dermatitis in all animals and no differences in severity of lesions were observed between vaccinated and unvaccinated control goats. Vaccination with each fraction of the mite proteins invoked high levels of scabies-specific IgG in the serum of all animals but failed to induce specific IgE as determined by Elisa. In contrast, goats challenged experimentally with a primary or repeated mite challenge developed strong serum IgE and IgG antibody responses to Sarcoptes antigens. The latter animals were shown in a previous study to be resistant to reinfestation. The lack of immune protection in the vaccinated animals may be attributed to the absence of protective levels of IgE antibody, and the present findings indicate that allergens and IgE antibody is important in immunity to S. scabiei infection.

Development of an in vitro system for the study of allergens and allergen-specific immunoglobulin E and immunoglobulin G: Fce receptor I supercross-linking is a possible new mechanism of immunoglobulin G-dependent enhancement of type I allergic reactions

BACKGROUND

IgE-dependent activation of mast cells (MCs) is a key pathomechanism of type I allergies. In contrast, allergen-specific IgG Abs are thought to attenuate immediate allergic reactions by blocking IgE binding and by cross-linking the inhibitory Fcgamma receptor IIB on MCs.

OBJECTIVES

To establish a defined in vitro system using human MCs to study the biological activity of allergens and to investigate the role of allergen-specific IgE and IgG.

METHODS

Purified human intestinal MCs sensitized with different forms of specific IgE Abs were triggered by monomeric and oligomeric forms of recombinant Bet v 1, the major birch pollen allergen, in the presence or absence of allergen-specific IgG Abs. Results MCs sensitized with an anti-Bet v 1 IgE mAb or sera obtained from birch pollen allergic patients released histamine and sulphidoleukotrienes after exposure to oligomeric Bet v 1. Monomeric Bet v 1 provoked mediator release only in MCs sensitized with patients sera but not in MCs sensitized with anti-Bet v 1 IgE mAb. Interestingly, MC activation could be induced by supercross-linking of monomeric Bet v 1 bound to monovalent IgE on MCs with a secondary allergen-specific IgG pAb. By using IgG F(ab')2 fragments we provide evidence that this effect is not a result of IgG binding to Fcgamma receptors.

CONCLUSION

This assay represents a new tool for the in vitro study of MC activation in response to natural and genetically modified allergens. Fcepsilon receptor I supercross-linking by allergen-specific IgG Abs provides a possible new mechanism of IgG-dependent enhancement of type I allergic reactions.

Allergen-specific IgE and IgG4 are markers of resistance and susceptibility in a human intestinal nematode infection

IgG4 has been proposed to act as a 'blocking antibody' due to its ability to compete for the same epitopes as IgE thus preventing IgE-dependent allergic responses. IgG4 and IgE are both elevated in helminth infections and strong anti-parasite IgE responses are associated with resistance to infection. We wished to determine the relationship between anti-parasite IgG4 and IgE and Ascaris lumbricoides infection status. We examined anti-parasite responses, including antibody levels to recombinant Ascaris allergen-1A (rABA-1A), a target of serum IgE in endemic populations. Worm burden was indirectly estimated by measuring parasite egg output in a cross-sectional human population (N = 105). Levels of anti-parasite IgG4 and IgE in patients' plasma were quantified by immunoassay. Global anti-parasite antibody responses did not bear any significant relationships with intensity of Ascaris infection. Individuals who had detectable levels of IgE but not IgG4 to rABA-1A (11%) had lower average levels of infection compared with individuals who produced anti-rABA-1A IgG4 (40%) and sero-negative individuals (49%) (P = 0.008). The ratio of IgG4/IgE in rABA-1A responders positively correlated with intensity of infection (P < 0.025). IgG4 levels positively correlated with infection level in younger children (age 4-11) where average levels of infection were increasing (P = 0.038), whereas allergen specific IgE emerged as a correlate of immunity in older children and adults (age 12-36) where infection levels were decreasing (P = 0.048). Therefore, in a gastrointestinal helminth infection, differential regulation of anti-allergen antibody isotypes relate to infection level. Our results are consistent with the concept that IgG4 antibody can block IgE-mediated immunity and therefore allergic processes in humans.

Allergic diseases and asthma in relation to serum immunoglobulins and salivary immunoglobulin A in pre-school children: a follow-up community-based study

BACKGROUND

We have previously reported an association between low IgA and allergic manifestations in early childhood (0-2 years) and have now followed our cohort for an additional 2 years.

OBJECTIVE

To evaluate in a longitudinal community-based cohort study the association between maturation of Ig production and allergic manifestations in the first 4 years of life.

METHODS

A cohort of 161 randomly selected children was followed from birth to the age of 42-48 months and evaluated at 18-23 months (EV1; n = 179) and again at the age of 42-48 months (EV2; n = 161). Diagnoses were made with the help of a clinical questionnaire, physical examination and skin prick tests (SPTs) to 10 common allergens. Serum immunoglobulins were measured at EV1 and EV2, and salivary IgA (sal-IgA) at EV2.

RESULTS

Serum IgA, IgE, IgG1, IgG2 and IgG4 increased from 2 to 4 years of age (P < 0.001) and their levels showed close correlations (P < or = 0.01 for most comparisons). Children with one or more positive SPTs had lower serum IgA (P = 0.004) and IgG4 (P = 0.05) at EV2 than those who did not respond, and children who developed allergic rhinitis between EV1 and EV2 had low sal-IgA (P = 0.006) and IgG3 (P < 0.05) at EV2. Atopic eczema was associated with low sal-IgA at EV2, and children who developed eczema between EV1 and EV2 had significantly lower sal-IgA than those who recovered after EV1 (P = 0.02).

CONCLUSION

Allergic manifestations in predisposed children may be influenced by the rate of maturation of immunological components that counteract sensitization or inhibit effector mechanisms of allergy.

Multiple-mutation at a potential ligand-binding region decreased allergenicity of a mite allergen Der f 2 without disrupting global structure

We assessed the effect of multiple-mutations within one IgE-binding area on allergenicity of Der f 2. The triple-mutant of Der f 2, P34/95/99A, exhibited the most significant reduction of allergenicity and circular dichroism analysis showed that the global structure of Der f 2 was maintained in P34/95/99A. These results indicate that such a strategy is effective when designing allergen-vaccines, which achieve less allergenicity for a broad population of patients without disrupting the global structure. Structurally, Der f 2 is a member of the MD-2 related lipid-recognition proteins. The sites for the triple-mutation located on the characteristically charged entrance of a cavity and corresponded to the regions critical to ligand-binding in the Niemann-Pick type 2 disease protein and MD-2.

Recombinant allergens for immunotherapy. Where do we stand?

PURPOSE OF REVIEW

This review is an update regarding the development of recombinant allergens from the laboratory bench to clinical applications. Special attention will be given to the potential improvement of allergen-specific immunotherapy through the use of recombinant allergens.

RECENT FINDINGS

Currently used therapeutic allergen extracts suffer from several important disadvantages and therefore may be replaced by recombinant allergens in the near future. Recent studies indicate that recombinant allergen-based diagnostic tests can be used for selection of patients for immunotherapy and to analyse the mechanisms underlying immunotherapy. Furthermore, recombinant and peptide technologies have been used for the generation of allergy vaccines with reduced allergenic activity. Applying the new technologies, the vaccines can be formulated to target either B cells or T cells, or both cell types. Very recently, encouraging results were obtained in an immunotherapy trial performed with genetically engineered allergens.

SUMMARY

Recombinant allergen-based diagnostic tests will improve the selection of patients for immunotherapy. The first immunotherapy trial with recombinant allergens provides information about mechanisms underlying immunotherapy and holds promise that new types of allergy vaccines based on recombinant allergens will become available soon.

Hypoallergenic variants of the major latex allergen Hev b 6.01 retaining human T lymphocyte reactivity

Hev b 6.01 is a major allergen of natural rubber latex with sensitization of 70-86% of latex glove-allergic subjects. Recently, we mapped the immunodominant T cell sites of Hev b 6.01 to the highly IgE-reactive hevein (Hev b 6.02) domain. Hev b 6.01 contains 14 cysteine residues with multiple disulphide bridges stabilizing tertiary conformation. With the goal of a standardized specific immunotherapy we developed hypoallergenic Hev b 6.01 mutants by site-directed mutagenesis of selected cysteine residues (3, 12, 17, and 41) within the Hev b 6.02 domain. Peptides corresponding to the Hev b 6.02 domain of two of the mutants were also synthesized. These mutants and peptide variants showed markedly decreased or ablated latex-allergic patient serum IgE binding by immunoblotting and ELISA. Basophil activation testing confirmed markedly decreased activation with successive cysteine substitutions of the mutants and complete abrogation with the Hev b 6.02 (Cys 3, 12, 17, 41 Ala) peptide. Retention of T cell reactivity is crucial for effective specific immunotherapy and all mutants and peptide variants maintained their latex-specific T cell reactivity. The ablated allergenicity but retained T cell reactivity of the Hev b 6.02 (Cys 3, 12, 17, 41 Ala) peptide suggests this peptide is a suitable candidate for inclusion in a latex immunotherapy preparation.

Genetically modified allergens

For more than 90 years, allergen-specific immunotherapy, the only causative allergy treatment, has remained basically unchanged. The development of molecular biology techniques has led to the preparation of individual recombinant allergens from the most important allergen sources. Recombinant allergens can be used to determine the individual sensitization profile of allergic patients and have allowed the development of novel therapeutic tools. This article summarizes data on genetically modified recombinant allergen derivatives with reduced allergenic activity, which may be used to improve the safety and efficacy of specific immunotherapy.

Non-anaphylactic surface-exposed peptides of the major birch pollen allergen, Bet v 1, for preventive vaccination

BACKGROUND

Almost 100 million allergic patients are sensitized to the major birch pollen allergen, Bet v 1, a 17 kDa protein containing most of the IgE epitopes present in pollens of trees belonging to the Fagales order and plant-derived food.

OBJECTIVE

Our aim was to develop an approach for the rational design of B cell epitope-derived, non-allergenic peptide allergy vaccines.

METHODS

According to the three-dimensional (3-D) structure of birch pollen allergen, Bet v 1, six peptides comprising 25-32 preferably solvent-exposed amino acids were synthesized.

RESULTS

Because of lack of secondary structure, the peptides showed no allergenic activity in allergic patients. In a mouse model of birch pollen allergy, peptide vaccination induced Bet v 1-specific IgG and prevented IgE-mediated allergic sensitization to Bet v 1. The protective role of peptide-induced blocking antibodies is demonstrated by inhibition of allergic patients IgE binding to the allergen and by blocking of allergen-induced basophil degranulation.

CONCLUSION

Our results indicate the mechanistic importance of blocking antibodies for allergy vaccination and present a B cell epitope-based approach for the rational design of safe peptide allergy vaccines whenever the structure of the disease-eliciting allergen is known.

Evaluation of recombinant and native timothy pollen (rPhl p 1, 2, 5, 6, 7, 11, 12 and nPhl p 4)- specific IgG4 antibodies induced by subcutaneous immunotherapy with timothy pollen extract in allergic patients

BACKGROUND

Allergen immunotherapy is a widely accepted treatment for IgE-mediated allergies. The evaluation of immunotherapy-induced IgG4 antibodies based on allergen extract is questionable because the amount of allergen-extract-specific IgG4 to individual disease-eliciting allergens cannot be determined using crude allergen extracts. In this study, we examined the specific IgE and IgG4 serum binding profiles to individual Phleum pratense allergens in grass-pollen-sensitive patients who had received grass-pollen-specific immunotherapy (SIT).

METHODS

The study included 33 patients from North-West Italy. All suffered from seasonal rhinoconjunctivitis and/or asthma. A modified "cluster" regimen of injections of a standardized aluminium-adsorbed P.pratense extract, with once-weekly visits and 10 injections for 5 weeks followed by 3 weeks of maintenance injections was instituted. Patients' sera were analyzed for specific IgE and IgG4 reactivity to individual P. pratense allergens (recombinant Phl p 1, Phl p 2, Phl p 5, Phl p 6, Phl p 7, Phl p 11, Phl p12 and native Phl p 4) and natural P. pratense extract using the Pharmacia CAP system.

RESULTS

IgE reactivities to new allergen components were not detected by CAP in treated patients after 15 weeks and a cumulative dose of approximately 65 microg of the major allergen Phl p 5. Patients lacking specific IgE reactivity towards individual allergens at the start of SIT did not produce significant levels of specific serum IgG4 to serum IgE-negative allergens. On the other hand, an increase in specific IgG4 only to allergens to which patients were previously sensitized was observed. Significant increases in specific IgG4 levels to rPhl p 1 (p < 0.05), 2 (p < (0.01), 5 (p < 0.0001), 6 (p < 0.0001), 7 (p < 0.05), 11 (p < 0.05) and nPhl p 4 (p < 0.01) were observed after P. pratense extract immunotherapy. No significant rPhl p 12-specific IgG4 antibody increase was documented after treatment.

CONCLUSION

These findings suggest that Phl p 12 was underrepresented in the extract used, as indicated by the low specific IgG4 response induced by this grass-pollen-specific vaccine. Thus, the simple detection of specific serum IgG4 antibodies a few weeks after the start of SIT could represent a valuable tool to estimate the presence of relevant allergens in a given immunotherapeutic allergen extract.

Molecular Characterization of Polygalacturonases as Grass Pollen-Specific Marker Allergens: Expulsion from Pollen via Submicronic Respirable Particles

Grass pollen belong to the most important allergen sources involved in the elicitation of allergic asthma. We have isolated cDNAs coding for Bermuda grass (Cynodon dactylon) and timothy grass (Phleum pratense) pollen allergens, belonging to a family of pectin-degrading enzymes (i.e., polygalacturonases). The corresponding allergens, termed Cyn d 13 and Phl p 13, represent glycoproteins of approximately 42 kDa and isoelectric points of 7.5. rPhl p 13 was expressed in Escherichia coli and purified to homogeneity. Immunogold electron microscopy using rabbit anti-rPhl p 13 Abs demonstrated that in dry pollen group 13, allergens represent primarily intracellular proteins, whereas exposure of pollen to rainwater caused a massive release of cytoplasmic material containing submicronic particles of respirable size, which were coated with group 13 allergens. The latter may explain respiratory sensitization to group 13 allergens and represents a possible pathomechanism in the induction of asthma attacks after heavy rainfalls. rPhl p 13 was recognized by 36% of grass pollen allergic patients, showed IgE binding capacity comparable to natural Phl p 13, and induced specific and dose-dependent basophil histamine release. Epitope mapping studies localized major IgE epitopes to the C terminus of the molecule outside the highly conserved functional polygalacturonase domains. The latter result explains why rPhl p 13 contains grass pollen-specific IgE epitopes and may be used to diagnose genuine sensitization to grass pollen. Our finding that rabbit anti-rPhl p 13 Abs blocked patients' IgE binding to the allergen suggests that rPhl p 13 may be used for immunotherapy of sensitized patients.

Component-resolved diagnosis of house-dust mite allergy with purified natural and recombinant mite allergens

BACKGROUND

Mites belong to the most frequent and potent allergen sources. Immunotherapy with mite allergen extracts is frequently performed if allergen avoidance is not possible or successful. However, highly controversial results have been reported for mite-specific immunotherapy.

OBJECTIVE

The aim of this study was to develop diagnostic concepts that may contribute to an improved selection of patients for immunotherapy with Der p allergen extracts and that may be used for immunological monitoring of patients undergoing this treatment.

METHODS

The IgE reactivity profiles to Der p extract were determined in a Middle European mite-allergic population by IgE immunoblotting and by using a panel of seven purified natural or recombinant Der p allergens (nDer p 1, nDer p 4, rDer p 2, rDer p 5, rDer p 7, rDer p 8, rDer p 10). Furthermore, we investigated the sensitization and cross-reactivity to house-dust- and storage-mite allergen extracts by CAP FEIA measurements and by IgE competition studies.

RESULTS

More than 95% of the patients could be diagnosed with a combination of nDer p 1 and rDer p 2. With the methods used, we could discriminate mite-allergic patients who were mainly sensitized to the major Der p allergens (Der p 1, Der p 2) from patients with a broad sensitization profile, including highly cross-reactive allergens (e.g. Der p 10: tropomyosin) as well as reactivity to storage mites.

CONCLUSIONS

Diagnostic tests containing the major mite allergens (i.e. Der p 1, Der p 2) and highly cross-reactive mite allergens (e.g. Der p 10) may improve the diagnostic selection of patients for immunotherapy with Der p extracts. These tests may also be used for the immunological monitoring of patients undergoing immunotherapy.

IgG binding of mugwort pollen allergens and allergoids exposed to simulated gastrointestinal conditions measured by a self-developed ELISAtest

This study considers the influence of exposure to simulated gastrointestinal conditions (saliva, gut, intestine and acidic conditions of the gut) on IgG binding of unmodified allergens and three types of LMW allergoids of Artemisia vulgaris pollen extract obtained by means of potassium cyanate succinic and maleic anhydride. It also concerns the optimization of a self-developed ELISA assay for comparison of the specific IgG binding of mugwort pollen extract and modified mugwort pollen derivatives. The ELISA was conducted with a mugwort pollen extract coupled to the plate, using the sera from 12 mugwort- pollen allergic patients. The exposure to saliva fluid for 2 min did not influence the IgG binding properties of allergens and allergoids. Exposure of mugwort pollen allergens and LMW allergoids to the acidic conditions of the gut did not dramatically change their IgG binding properties. By exposing mugwort pollen extract and LMW derivatives to the SGF conditions for 1 h, the percent of IgG binding epitopes was reduced to a half of its starting value in the extract and to about 30%in all the allergoid samples. After prolonged exposure only the carbamyl derivative showed reduced IgG binding. Changes of the IgG binding potential of all four samples after exposure in SIF followed a similar pattern.