Allergi förekommer hos cirka 20 % av befolkningen i Sverige. Av de 20 % bedöms 40 % vara allergiska mot pollen. Allergi uppstår då en individ upprepade gånger exponeras för ett allergiframkallande ämne sk allergen. IgE-antikroppar bildas och binder till basofila granulocyter och mastceller. Den allergiska reaktionen eller överkänslighetsreaktionen av typ I uppkommer när ett allergen exempelvis pollen, kommer i direkt kontakt med IgE-antikroppar på mastceller eller basofila granulocyter. Allergiska individer har högre koncentration av IgE-antikroppar i blodet än icke allergiska. Normal koncentration av IgE i serum hos icke allergiker är <0.35 kU/L. Syftet med studien var att genom analys av serumprover från 50 patienter jämföra två immunokemiska metoder på analysinstrumenten, Siemens immulite® 2000 XPi och Thermo Fisher Phadia® 250, för detektion av IgE-antikroppar riktade mot en inhalationspanel respektive björkpollen. Immulite® 2000 XPi användes som referensmetod. Jämförelsen gjordes för att bedöma om metoderna gav överensstämmande resultat och om Phadia® 250 skulle kunna användas som ett alternativ till rutinmetoden. Studiematerialet bestod av 50 patienter i åldrarna 18–80 år, 17  män (34 %) och 33 kvinnor (66 %). Resultatet visade att metoderna överlag gav överrensstämmande resultat med avseende på positiva och negativa IgE-värden, men att de uppmätta värdena för metoderna saknade överrensstämmelse. Analysresultaten från de båda metoderna gav överlag god korrelation vid analys av specifikt IgE mot björk (R=0,977) men en svagare korrelation vid analys av inhalationspanel (R=0,609). Med hjälp av Man-Whitney u-test sågs en signifikant skillnad vid IgE-analys mot björk (p= 0,0006) däremot sågs inte en signifikant skillnad mellan metodernas IgE-värden mot inhalationspanelerna (p=0,2398). För att kunna utvärdera om Phadia® 250 skulle kunna användas som ett alternativ till rutinmetoden, krävs en större population av prover samt fler analystillfällen. / Allergy is nowadays a public health problem that’s affecting 20 % of the Swedish population. A very common allergen that is related to 40% of all the allergic cases is pollen. Allergic reactions occur when an  individual is repeatedly exposed to an allergenic substance called allergene. IgE antibodies then form and bind to basophilic granulocytes and mast cells. The allergic reaction or type I hypersensitivity reaction, occurs when an allergen such as pollen comes into direct contact with IgE antibodies on mast cells or basophilic granulocytes. IgE is produced by plasma cells under the influence of CD4+ T lymphocytes. The IgE antibodies synthesized then sensitize the mast cells and basophilic granulocytes which are the most active cell types involved in allergic reactions. Allergic individuals have a higher concentration of IgE antibodies in the blood than non-allergic. Normal serum IgE concentration in non-allergic patients is <0.35 kU / L. The aim of the study was to compare two immunochemical instruments, Siemens Immulite® 2000 XPi and Thermo Fisher Phadia® 250, by analyzing 50 serum samples to detect possible presence of IgE antibodies directed against an inhalation panel and a single allergen (IgE against birch). The study material consisted of 50 patients between the ages of 18-80, 17 men (34%) and 33 women (66%). The results showed that overall the two methods yielded consistent results due to positive and negative IgE values, but the measured values of the methods lacked concordance. The analysis results from the two methods generally yielded good correlation in the analysis of specific IgE against birch (R = 0.977) but a weaker correlation in the inhalation panel analysis (R = 0.609). Man-Whitney u-test showed a significant difference in IgE analysis against birch (p = 0.0006). However, a significant difference between the IgE values of the methods against the inhalation panels (p = 0.22398) was not observed. To be able to evaluate whether Phadia® 250 could be used as an alternative to the routine method, a larger population of samples and more analytical occasions is required.

Tesis por compendio / [EN] About 10 % of all adverse drug reactions are due to allergies, with ß-lactam antibiotics causing the majority of the episodes. Although the actual incidence remains unknown, individuals suspected of being allergic to a drug end up being prescribed with other medications that are less effective, more expensive or harmful. Consequently, a correct diagnosis is key to reduce the derived economic costs and proceed to an adequate 'delabeling' of the population. At present, clinical approaches to diagnose allergies to ß-lactam antibiotics are based on in vivo and in vitro tests. These tests present limited clinical performances since they are invasive, dangerous, and provide false positives and/or negatives. Moreover, the diagnostic sensitivity is far from what is expected, possibly because the epitopes that cause the allergic episodes are still not well detected. In this respect, the preparation of antigens has commonly been determined by the direct attachment of antibiotics to carrier molecules through the formation of an amide bond between amino lysine groups of the carrier molecule and the carboxylate group of the antibiotic. Even so, specific IgE are barely detected with such antigens. This dissertation addresses the synthesis of haptens and the generation of antigens to ß-lactam antibiotics, which develop a more reliable in vitro diagnosis of allergies to these drugs. The evaluation of the antigens has been carried out by means of multiplex in vitro tests based on compact disc technology. This research begins by focusing on the synthesis and preparation of penicillin antigens. To this end, first, the effect of the incorporation of aliphatic spacer arms in the chemical structure of penicillin has been approached, considering the possibility that a better molecular recognition is obtained by moving the hapten away from the carrier protein. Thirteen haptens derived from benzylpenicillin and amoxicillin were synthesized in order to prepare antigens with human serum albumin. The evaluation of the antigens revealed that even though they were immunogenic and were detected by the raised IgG antibodies, they were not detected by specific IgE from allergic patients. Additionally, the next approach considered the cationization of the carrier proteins, human serum albumin and histone. The modification of carboxylate groups of the protein to amino groups allow for an increase of the molar hapten/protein ratio. This strategy led to the generation of five antigens, four of which (only those histone-based antigens), did increase the sensitivity of the assay. Concretely, specific IgE has been determined in sera from allergic patients at low concentrations (LOD = 0.07 IU/mL) with a diagnostic specificity of 100 % and a sensitivity of 60 and 31 % for benzylpenicillin and amoxicillin, respectively. That means a 60 % improvement in the diagnostic sensitivity when compared to the in vitro reference test. Subsequently, the idea of preparing minor antigens based on penicillin metabolites was approached. Penicilloic, penilloic, penicillic, and 6-aminopenicillanic acids, together with penicillamine, were therefore conjugated to the carrier proteins human serum albumin and histone. Except penilloic acid, the rest of antigens were selectively detected when testing a set of serum samples from allergic patients. The diagnostic specificity obtained was 100 %, 94 % in the case of penicillic acid, and the sensitivity was between 67 and 100 %. Another approach was focused on the production of antigens for other families of ß-lactam antibiotics. The generation of antigens for cephalosporins, carbapenems, monobactams or ß-lactam inhibitors is essential, since in vitro tests for the detection of allergies to these antibiotics are not commercially available. Therefore, the results obtained after the preparation of major and minor antigens for the antibiotics cefuroxime, cefotaxime, ceftriaxone, meropenem, and aztreonam were evaluated. / [ES] Alrededor del 10 % de las reacciones adversas a medicamentos son debidas a alergias, siendo los antibióticos ß-lactámicos los que más episodios alérgicos ocasionan. Aunque la incidencia real sigue siendo desconocida, los individuos sospechosos de presentar alergia a algún medicamento acaban siendo prescritos con otros medicamentos, menos efectivos, más caros o perjudiciales. Así pues, un correcto diagnóstico resulta clave para disminuir los costes económicos derivados y proceder a un adecuado 'desetiquetado' de la población. En la actualidad, las pruebas de diagnóstico de alergias a antibióticos ß-lactámicos se basan en ensayos in vivo e in vitro. Estos ensayos muestran bajas prestaciones, ya que son invasivos y peligrosos y proporcionan falsos positivos y/o negativos. Además, la sensibilidad diagnóstica está lejos de ser la esperada, posiblemente porque aún no se ha conseguido reconocer todos los epítopos causantes de los episodios alérgicos. En este sentido, la preparación de antígenos se ha basado hasta el momento, en mayor medida, en la unión directa de los antibióticos a las moléculas portadoras mediante la formación de un enlace amida entre los grupos amino de las lisinas de la molécula portadora y el grupo carboxilato del antibiótico. Aun así, las IgE específicas son vagamente detectadas con estos antígenos. En esta tesis se ha abordado la síntesis de haptenos y la generación de determinantes antigénicos a antibióticos ß-lactámicos con los que poder realizar un diagnóstico in vitro más fiable de alergias a estos fármacos. La evaluación de los mismos se ha llevado a cabo mediante ensayos in vitro multiplex basados en tecnología de disco compacto. Esta investigación comienza centrándose en la síntesis y preparación de antígenos de penicilina. Para ello, en una primera fase se ha estudiado el efecto de la incorporación de brazos espaciadores alifáticos en la generación de antígenos, considerando la posibilidad de que se obtenga un mejor reconocimiento molecular al alejar el hapteno de la proteína portadora. Se sintetizaron trece haptenos derivados de bencilpenicilina y amoxicilina con los que se prepararon antígenos con la proteína albumina de suero humano. La evaluación de los antígenos reveló que a pesar de ser suficientemente inmunogénicos y ser reconocidos por anticuerpos IgG de conejo, éstos no fueron reconocidos por IgE específicas de muestras de pacientes alérgicos. Así bien, por otro lado, la estrategia de cationización de las proteínas albumina de suero humano e histona fue abordada teniendo en cuenta que la modificación de grupos carboxilatos de la proteína a grupos amino aumenta la relación molar hapteno/proteína. Esta estrategia permitió la generación de 5 antígenos, 4 de los cuales (los antígenos de histona), esta vez sí, incrementaron la especificidad de la respuesta inmunológica obtenida, reconociendo IgE específicas. Concretamente, se han determinado IgE específicas en suero de pacientes alérgicos a bajas concentraciones (LOD = 0.07 IU/mL) con una especificidad diagnóstica del 100 % y una sensibilidad del 60 y 31 % para bencilpenicilina y amoxicilina, respectivamente, mejorando la sensibilidad un 60 % en comparación con el ensayo in vitro de referencia. A pesar de las mejoras obtenidas con las estrategias llevadas a cabo, se estudiaron otras vías no clásicas para la síntesis de nuevos haptenos con mayor diversidad química. Este enfoque se basa en la generación de antígenos en librerías químicas de compuestos con diversidad estructural para encontrar nuevos haptenos biológicamente activos. Dichas estrategias, hasta el momento, no han sido empleadas para la generación de antígenos y el análisis de muestras de suero de pacientes alérgicos. Con el fin de incorporar diversidad estructural, se sintetizaron, mediante la técnica combinatoria diversity-oriented synthesis, 22 compuestos de los precursores de las penicilinas y cefalosporinas, ácido 6-aminopenicilánico y ácido 7-amino-desacetoxicefalosporánico, respectivamente, y de los antibióticos amoxicilina y ampicilina. Su evaluación con el inmunoensayo in vitro basado en disco compacto ha demostrado que la incorporación de diversidad permite el reconocimiento de epítopos causantes de episodios alérgicos. Concretamente, se observó que estos antígenos eran capaces de detectar anticuerpos tipo IgG e IgE específicos procedentes de suero de conejos inmunizados y de suero humano de pacientes alérgicos, siendo especialmente selectivos los determinantes de amoxicilina y ampicilina. Concretamente, se obtuvo una sensibilidad diagnóstica del 79 % y una especificidad diagnóstica del 100 % / [CA] Al voltant del 10% de les reaccions adverses a medicaments són degudes a al·lèrgies, sent els antibiòtics ß-lactàmics aquells que més episodis al·lèrgics ocasionen. Encara que la incidència real continua sent desconeguda, els individus sospitosos de presentar al·lèrgia a algun medicament acaben sent prescrits amb altres medicaments, menys efectius, més cars o perjudicials. Així doncs, un correcte diagnòstic resulta clau per a disminuir els costos econòmics derivats i procedir a un adequat 'desetiquetatge' de la població. En l'actualitat, les proves de diagnòstic d'al·lèrgies a antibiòtics ß-lactàmics es basen en assaigs in vivo i in vitro. Aquests assaigs mostren baixes prestacions, ja que són invasius i perillosos i proporcionen falsos positius i/o negatius. A més a més, la sensibilitat diagnòstica està lluny de ser l'esperada, possiblement perquè encara no s'ha aconseguit reconéixer tots els epítopes causants dels episodis al·lèrgics. En aquest sentit, la preparació d'antígens s'ha basat fins al moment, en major mesura, en la unió directa dels antibiòtics a les molècules portadores mitjançant la formació d'un enllaç amida entre els grups amino de les lisines de la molècula portadora i el grup carboxilat de l'antibiòtic. Així i tot, les IgE específiques són vagament detectades amb aquests antígens. En aquesta tesi s'ha abordat la síntesi d'haptens i la generació de determinants antigènics a antibiòtics ß-lactàmics amb els quals poder realitzar un diagnòstic in vitro més fiable d'al·lèrgies a aquests fàrmacs. La seua avaluació s'ha dut a terme mitjançant assaigs in vitro multiplex basats en tecnologia de disc compacte. Aquesta investigació comença centrant-se en la síntesi i preparació d'antígens de penicil·lina. Per a això, en una primera fase s'ha estudiat l'efecte de la incorporació de braços espaiadors alifàtics en la generació d'antígens, considerant la possibilitat que s'obtinga un millor reconeixement molecular en allunyar l'haptè de la proteïna portadora. Es van sintetitzar tretze haptens derivats de bencilpenicil·lina i amoxicil·lina amb els quals es van preparar antígens amb la proteïna albúmina de sèrum humà. L'avaluació dels antígens va revelar que malgrat ser prou immunogènics i ser reconeguts per anticossos IgG de conill, aquests no van ser reconeguts per IgE específiques de mostres de pacients al·lèrgics. Així bé, d'altra banda, l'estratègia de cationització de les proteïnes albúmina de sèrum humà i histona va ser abordada tenint en compte que la modificació dels grups carboxilats de la proteïna a grups amino augmenta la relació molar hapten/proteïna. Aquesta estratègia va permetre la generació de 5 antígens, 4 dels quals (els antígens d'histona), aquesta vegada sí, van incrementar l'especificitat de la resposta immunològica obtinguda, reconeixent IgE específiques. Concretament, s'han determinat IgE específiques en sèrum de pacients al·lèrgics a baixes concentracions (LOD = 0.07 IU/mL) amb una especificitat diagnòstica del 100 % i una sensibilitat del 60 i 31 % per a bencilpenicil·lina i amoxicil·lina, respectivament, millorant la sensibilitat un 60 % en comparació amb l'assaig in vitro de referència. Malgrat les millores obtingudes amb les estratègies dutes a terme, es van estudiar altres vies no clàssiques per a la síntesi de nous haptens amb major diversitat química. Aquest enfocament es basa en la generació d'antígens en llibreries químiques de compostos amb diversitat estructural per a trobar nous haptens biològicament actius. Aquestes estratègies, fins al moment, no han sigut emprades per a la generació d'antígens i l'anàlisi de mostres de sèrum de pacients al·lèrgics. Amb la finalitat d'incorporar diversitat estructural, es van sintetitzar, mitjançant la tècnica combinatòria diversity- oriented synthesis, 22 compostos dels precursors de les penicil·lines i cefalosporines, àcid 6-aminopenicilànic i àcid 7-amino-desacetoxicefalosporànic, respectivament, i dels antibiòtics amoxicil·ina i ampicil·lina. La seua avaluació amb l'immunoassaig in vitro basat en disc compacte ha demostrat que la incorporació de diversitat permet el reconeixement d’epítops causants d'episodis al·lèrgics. Concretament, es va observar que aquests antígens eren capaços de detectar anticossos tipus IgG i IgE específics procedents de sèrum de conills immunitzats i de sèrum humà de pacients al·lèrgics, sent especialment selectius els determinants d’amoxicil·lina i ampicil·lina. Concretament, es va obtindre una sensibilitat diagnòstica del 79 % i una especificitat diagnòstica del 100 %. / This work was supported by the H2020 program (project COBIOPHAD, grant agreement No. 688448 awarded to A.M.), being an initiative of the Photonics Public Private Partnership; Agencia Estatal de Investigación Agencia Estatal de Investigación (CTQ2016-75749-R, FEDER) (PID2019-110713RB-I00, FEDER) awarded to S.M.; Generalitat Valenciana (PROMETEO/2020/094 awarded to A.M. & S.M.); program UPV-La FE 2019 (P105 VALBIOAL awarded to S.M & E. I-E.); and the National Institute of General Medical Sciences (GM-1R35GM127045 awarded to S.L.S.). E.P.M. was supported by a FPU fellowship from the Ministerio de Educación, Cultura y Deporte (FPU15/01738 and EST18/00360). B.K.H. was supported by a fellowship from the National Science Foundation (DGE1144152 and DGE1745303). The authors acknowledge the Instituto de Investigación Sanitaria La Fe, Valencia, Spain, which provided the samples from both allergic patients and controls. / Peña Mendizabal, E. (2022). Synthesis and Evaluation of Antigenic Determinants for ß-lactam Allergy Diagnosis [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/182979 / TESIS / Compendio

Background: Allergic sensitization is the most important risk factor for asthma and rhinitis among children, adolescents and young adults. Less is known about the incidence and remission of allergic sensitization, particularly in older adults. Furthermore, it is not clear if the earlier documented increase in prevalence of allergic sensitization continues. This thesis is focused on prevalence, incidence and remission of allergic sensitization to airborne allergens among adolescents and adults as well as on time trends in prevalence among adults. Furthermore, associated risk factors and the relation of allergic sensitization to asthma and rhinitis were assessed. Methods: In the study of children and adolescents, incidence, remission and prevalence of allergic sensitization were assessed in a cohort study of schoolchildren, aged 7-8 years (y) at baseline. In the studies of adults, incidence and remission of allergic sensitization were assessed in a randomly selected adult population sample in 1994 (n=664) aged 20-69 y, which was followed up in 2004 (n=555). Trends in prevalence of allergic sensitization were assessed by comparing two cross-sectional studies; the cohort from 1994 and another randomly selsected population sample examined in 2009 (n=737). The relation of allergic sensitization to asthma and rhinitis was determined in the adult cohort in 2009. Allergic sensitization was assessed by skin prick test (SPT) with ten common airborne allergens at ages 7-8, 11-12 and 19 y in the cohort of children and in the participants ≤ 60 y in the adult cohorts. Specific IgE to nine airborne allergens was analyzed in the adult cohorts in 2004 and 2009. Risk factors for allergic sensitization and variables defining respiratory disease and symptoms were assessed by questionnaires in the cohort of children and by structured interviews in the adult cohorts. Results: The 10-year cumulative incidence of allergic sensitization among the adults from 1994 to 2004 was 5%, while remission was 32%. In both adult cohorts, the prevalence of allergic sensitization was highest among young adults, aged 20-29 y, 55% and 61% and decreased significantly with increasing age. Among children and adolescents, both incidence and persistence of allergic sensitization were high, and the prevalence of allergic sensitization increased by age from 21% at age 7-8 y to 42% at age 19 y. Multisensitization at age 19 y was strongly associated with early onset of sensitization. The prevalence of sensitization to the major specific allergens birch, timothy, cat and dog as well as multisensitization (from 40% in 1994 to 56% in 2009, p=0.002) increased significantly from 1994 to 2009 among the adults. Sensitization to any allergen increased from 35% to 39%, however not significantly (p=0.13). A family history of allergic rhinitis was strongly and consistently associated with allergic sensitization in all ages. Male sex and urban living were significantly positively and birth order and furry animals at home in childhood were negatively associated with onset of sensitization before the age of 7-8 y, but not with onset of sensitization from 11-12y to 19 y. Young adult age and urban living were significant factors associated with allergic sensitization in adult age. Sensitization to any animal was significantly positively associated with current asthma (OR4.80 (95% CI 2.68-8.60)), whereas both sensitization to any pollen (OR 4.25 (2.55-7.06)) and any animal (OR 3.90 (95% CI 2.31-6.58)) were associated with current allergic rhinitis. The association between allergic sensitization and allergic rhinitis was strongest in young adult age and decreased with increasing age, while asthma was similarly associated with sensitization to any animal across all adult ages. Among asthmatics, the prevalence of allergic sensitization decreased with increasing age of asthma onset. Conclusion: Both incidence and persistence of allergic sensitization were high among children and adolescents explaining the increase in prevalence by increasing age. An inverse pattern with low incidence and high remission of allergic sensitization was seen among adults. The decrease in prevalence of allergic sensitization by increasing adult age might at least partly be explained by normal ageing and not only by an effect of year of birth (cohort effect). The significant increase in prevalence of sensitization to the specific allergens explained the significant increase in multisensitization over 15 years. A family history of allergy was the strongest and the only consistent risk factor for allergic sensitization in all ages. The prevalence of allergic sensitization decreased with increasing age of asthma onset among adult asthmatics.

<p>Background: The reasons why some individuals become IgE-sensitised and allergic are largely unknown, though genetic- and early life environmental factors seem to be of importance.</p><p>Objective: The overall aim of this thesis was to investigate the relationship between IgE-sensitisation and allergic disease, viral infections, genetic markers and early life cytokines.</p><p>Results: IgE-sensitised children were found to have reduced numbers of IL-12 producing cord blood mononuclear cells (CBMC), whereas children diagnosed with eczema were found to have reduced numbers of IFN-γ producing CBMC. When dividing the children into early onset of IgE-sensitisation and late onset of IgE-sensitisation we found that the children with an early onset had low numbers of PHA-induced IL-4, IL-12 and IFN-γ secreting CBMC. At the age of two there was a general exacerbation of cytokine responses in the IgE-sensitised children, and the results were similar for the children with early onset IgE-sensitisation. Children with a late onset IgE-sensitisation were more similar to the non-sensitised children, but with a specific increase in the response to cat allergen (IL-4 and IFN-γ). The mothers of IgE-sensitised children, were just as their children, found to have an exaggerated cytokine response as compared to mothers of non-sensitised children. Maternal responses correlated well to the responses seen in the child, though the samples were taken two years after delivery.</p><p>Cytomegalovirus (CMV) infection in early life was associated to reduced numbers of IL-4, and increased numbers of IFN-γ producing cells at the age of two. No association between CMV seropositivity and IgE-sensitisation was seen. Epstein-Barr virus (EBV) infection, on the other hand, was inversely correlated with IgE –sensitisation, whereas no statistically significant association to cytokine production could be seen.</p><p>We also showed that the IL12B 1188 C-allele was associated to having a positive skin prick test at the age of two. The rare alleles of the three SNPs investigated (IL12B 1188C, IL12RB1132C and IRF1 1688A) were all associated to low IL-12 production at birth.</p><p>Conclusions: Our results indicate that allergic diseases are complex traits, and that both the genetic and the cytokine background differ between the different allergic diseases. We can also conclude that the time of onset seem to play a role when investigating IgE-sensitisation, and that perhaps early and late onset IgE-sensitisation have partly different causes. CMV and EBV infection early in life are associated to a protective cytokine profile and to protection from IgE-sensitisation, respectively, again indicating the heterogeneity and the complexity of allergic diseases.</p>

Mast cell progenitors originate from the bone marrow and migrate to the lungs via the blood. During maturation, these cells acquire granules that contain a potent array of bronchoconstrictive mediators. The number of pulmonary mast cells is augmented in asthmatic patients and in mice with allergic airway inflammation, possibly contributing to airway hyperreactivity. An increase in mast cells is likely due to an increased recruitment of committed mast cell progenitors from the blood. However, until now a committed mast cell progenitor population has not been found in adult peripheral blood. We isolated Lin- c-kithi ST2+ integrin β7hi CD16/32hi progenitors from murine blood and showed that these cells were committed to the mast cell lineage. Based on the expression of FcεRI, these cells were less mature in Th1-prone C57BL/6 mice than in Th2-prone BALB/c mice. Asthma is associated with elevated levels of IgE. Upon exposure to allergens, IgE immune complexes are formed. In a mouse model of allergic airway inflammation, we showed that intranasal administration of IgE immune complexes to antigen-sensitized mice resulted in an increased number of mast cell progenitors compared with antigen administration alone. The increase in mast cell progenitors was independent of the low-affinity IgE receptor CD23. Rather, signaling through the common FcRγ-chain was required to enhance the number of lung mast cell progenitors. Signaling through FcεRI was likely responsible for the increase. However a role for FcγRIV could not be excluded. CD11c+ cells, such as dendritic cells, are important for antigen sensitization. In a mouse model of allergic airway inflammation, these cells are also important for the development of airway hyperreactivity, eosinophilia and Th2 cytokine production in response to antigen challenge. We showed that CD11c+ cells are critical for the recruitment of lung mast cell progenitors and the subsequent increase in mast cells. These CD11c+ cells were needed for the upregulation of endothelial vascular cell adhesion molecule-1 (VCAM-1), which is a prerequisite for the antigen-induced recruitment of lung mast cell progenitors.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Fluvastatin, the HMG-CoA reductase inhibitor known for its role in the treatment of hypercholesterolemia and cardiovascular disease, has more recently been shown to play a role in the immune response. Given the critical role that mast cells play in allergy and inflammatory diseases such as asthma, which effects one third of America’s population, we assessed the effect of fluvastatin on mast cell and basophils function. We demonstrate that fluvastatin downregulated IgE-mediated cytokine production. Additionally, in vivo studies showed that fluvastatin suppressed IgE-mediated anaphylaxis. Interestingly, the effects of fluvastatin showed dependence on genetic background, as C57BL/6 mast cells were sensitive, while 129/Sv mast cells were resistant to fluvastatin. Characterizing the role of fluvastatin on mast cells may prove to be therapeutically important.

Through underexpression and overexpression studies, CD23 has been shown to negatively regulate IgE production. To investigate CD23 destabilization and its effects on CD23 shedding and IgE synthesis in vivo, we utilized an anti-CD23 stalk monoclonal (19G5) which has previously been shown to enhance proteolysis of CD23 in vitro. Compared to isotype control-treated mice, mice injected with 19G5 displayed enhanced serum soluble CD23 and IgE. Because 19G5 injection substantially enhanced CD23 shedding, it was useful in investigating the identity of the CD23 sheddase. 19G5 enhanced CD23 shedding in ADAM8-/-, ADAM9-/-ADAM15-/-, and ADAM9-/-ADAM12-/-ADAM15-/- mice, ruling out these ADAMs as candidate CD23 sheddases. Through the use of an ADAM10 inhibitor, we blocked CD23 shedding from murine B cells while increasing CD23 surface levels, and thus we identified ADAM10 as the CD23 sheddase. During the course of the ADAM investigation, we discovered that the 129/SvJ inbred mouse strain carried five amino acid substitutions within its CD23 gene. The mutations resulted in reduced CD23 surface expression and hyper IgE levels in vivo. The hyper IgE phenotype was consistent with a more rapid clearance of Nippostrongylus brasiliensis from the gut of 129/SvJ mice. B cells from 129/SvJ spleens proliferated more rapidly than those from BALB/c after stimulation with IL-4 and CD40 ligand trimer in vitro. However, in vitro IgE levels in supernatants from 129/SvJ B cells were significantly reduced, suggesting that the B cells were no longer responsive to IL-4 in vitro. Although the affinity of the IgE-129/SvJ CD23 interaction was similar to that of the BALB/c, 129/SvJ B cells exhibited a reduced number of IgE binding sites, demonstrating that high levels of CD23 are essential for controlling IgE synthesis. This finding was further confirmed in another disease model, namely the mouse asthma model. Mice overexpressing CD23 displayed suppressed allergic lung inflammation and reduced levels of IgE and Th2 cytokines and chemokines. Overall, the data provide a direct demonstration for CD23's role in regulating IgE production in vivo and suggest that therapies aimed at stabilizing cell surface CD23 would inhibit proteolysis and increase surface expression, and thus would be beneficial in controlling allergic disease.

ADAM10 is a zinc-dependent metalloprotease. ADAM10 has emerged as a key regulator of cellular processes by cleaving and shedding extracellular domains of multiple transmembrane receptors and ligands. In this study, we examined the role of ADAM10 in the immune system. Here, we show that knocking out ADAM10 on the mature B2 cell causes a defect in the development of secondary lymphoid architecture that becomes more severe post-immunization. We also show that overexpression of ADAM10 leads to a defect in hematopoiesis, which eliminates B2 lymphocyte development. This defect additionally induces accumulation of myeloid derived suppressor cells, MDSCs. ADAM10Tg MDSCs function synonymous to tumor MDSCs. Of the two subpopulations of MDSCs, granulocytic MDSCs increase parasitic clearance in a model of N. brasiliensis. Monocytic MDSCs are more immunosuppressive in regards to tumor. Both subpopulations are dependent on the presence of mast cells for activity. It is thought that this relationship is mediated through histamine and IL-13. During N. brasiliensis infection, ADAM10Tg mice, lacking B2 B cells but having intact B1 B cells, makes increased IgE over WT mice. This production of IgE is thought to be produced by the B1 cells. Of the two types of B1 cells, B1a cells make the majority of the IgE. This IgE production is enhanced by MDSC accumulation and can be induced by MDSC adoptive transfer in a parasite-free mouse. Lastly, ADAM10 is the key sheddase for CD23 on B2 cells. When IgE is bound to its antigen to form an immune complex, IC, it binds CD23 and is internalized. After CD23 bound to IgE ICs is internalized, it is sorted into bexosomes. These bexosomes are transferred to dendritic cells which are responsible for presenting to T cells and inducing an increased antigen-specific immune response. Overall, ADAM10 is important for many aspects of the immune response.