A major advantage of DNA vaccination is the ability to induce both humoral and cellular immune responses. DNA vaccines are currently used in veterinary medicine, but their tendency to display low immunogenicity in humans has hindered their usage, despite excellent tolerability and safety profiles. Various approaches have been used to improve the immunogenicity of DNA vaccines. Recent human study data re-established the value of DNA vaccines, especially in priming high-level antigen-specific antibody responses. Data suggests that innate immune responses to the DNA vaccine plasmid itself contribute to the immunogenicity of DNA vaccines, however the underlying mechanisms responsible remain unclear. In this dissertation, we investigate the role of innate immunity in shaping antigen-specific adaptive immune responses following DNA vaccination. The current belief is that the cytosolic DNA sensing pathways govern DNA vaccine immunogenicity. To date, only the type I interferon inducing STING/TBK1 regulatory pathway has been identified as required for DNA vaccine immunogenicity. Surprisingly, neither the upstream receptor nor the downstream signaling molecules in this pathway have been characterized. I therefore investigated a candidate cytosolic DNA receptor, as well as the downstream transcription factors required for generation of antigen-specific immune responses. Additionally, the effects of pro-inflammatory signaling on DNA vaccine immunogenicity have yet to be comprehensively studied. Previous studies have only provided indirect evidence for the role of inflammatory v signaling in DNA vaccination. As such, I also investigated the role of the DNA sensing AIM2 inflammasome in DNA vaccination. My data indicates that AIM2 is a key modulator in DNA vaccination via a previously unrecognized connection to type I interferon. Importantly, this marks the first time a DNA vaccine sensor has been identified. Of note, this dissertation represents a departure from many published works in the field. Whereas previous studies have mostly utilized model antigens and only focused on the adaptive immune responses generated, I analyzed the effects on innate immunity as well. Using various innate gene knockout murine models, I quantified antigen-specific humoral and T cell responses, as well as serum cytokine and chemokines following immunization with a clinically relevant DNA vaccine. Overall, this data provides a basis for understanding the mechanisms of DNA vaccination, allowing for the design of more effective vaccines.

Introdução: O carcinoma epidermóide de cabeça e pescoço avançado é uma doença de difícil tratamento. Apesar dos avanços nas técnicas de diagnóstico e tratamento nos últimos 30 anos não ocorreram ganhos significativos em sobrevida. A falha no tratamento ocorre principalmente pela recidiva locorregional e freqüentemente impede a realização de tratamentos de resgate. Com o desenvolvimento da imunoterapia novas abordagens tem sido descritas para o combate ao câncer. Estudos em animais demonstraram a redução de tumores com a utilização de vacinas de DNA contendo a HSP-65 do Mycobacterium leprae. Neste estudo avaliou-se a utilização desta proteína em pacientes portadores de carcinoma epidermóide de cabeça e pescoço em estádio avançado e fora de possibilidades terapêutica curativa pelos métodos convencionais. Objetivos: Testar a viabilidade de realização da injeção intratumoral do DNA HSP65 nesse grupo de doentes, avaliar a resposta tumoral através da análise comparativa do volume, pesquisar a transfecção do DNA HSP65 do M. Leprae e verificar se o tratamento realizado apresentou impacto na evolução dos pacientes. Casuística e métodos: Foram incluídos 21 pacientes em três grupos. Cada grupo recebeu diferentes doses da vacina de DNA HSP-65 do Mycobacterium leprae: 150, 600 e 400µg, através de aplicações intratumorais guiadas por ultra-som com Doppler. Foram realizadas tomografias computadorizadas antes e após o tratamento, para avaliação da resposta tumoral através da comparação de volume tumoral. Realizaram-se biópsias antes e após o tratamento, e o material foi submetido a reação em cadeia da polimerase (Rt-PCR) para identificar a transfecção do DNA injetado. Durante o protocolo os pacientes foram acompanhados para observação de eventos adversos que pudessem ser relacionados à medicação. Resultados: Dos 21 pacientes, sete faleceram antes do término do protocolo. Nos 13 pacientes passíveis de análise, ocorreram quatro respostas parciais e estabilidade da lesão em um caso. Em nove casos houve progressão da doença. Dois pacientes encontram-se vivos em seguimento a mais de oitocentos dias do inicio do protocolo. Os eventos adversos ocorridos foram principalmente aumento da dor local e edema. Não foi possível comprovar a transcrição do DNA injetado no Rt-PCR pela ocorrência de um resultado falso positivo. Conclusões: A aplicação foi segura na dose de 400µg por aplicação. Não foi possível comprovar a transfecção de DNA de HSP65. Nos pacientes que apresentaram diminuição do volume tumoral parece ter havido benefício clínico. / Introduction: The squamous cell carcinoma of the head and advanced neck is an disease difficult to treat. Despite the advances in diagnosis and treatment in last the 30 years had not occurred major survival improvements. The treatment failure occurs mainly locorregionaly and recurrences frequently canot be rescued. immunotherapy has had encouraging results in the last years. Studies in animals had demonstrated the reduction of tumors with the DNA vaccine containing HSP-65 of the Mycobacterium leprae. In this study we evaluate the use of this protein in patients with avdanced head and neck carcinoma, stages II and IV without possibilities of curative treatment. Objectives: To test the viability of accomplishment of the intratumoral injection of DNA HSP65 in this group of patients, test its effectiveness through the comparative analysis of the volume, to verify transfeccion of the DNA injected and to see if the carried through treatment presented impact in the evolution of the patients. Patients and methods: 21 patients in 3 groups of doses 150,600 and 400µg of the vaccine of DNA HSP-65 of M leprae, through intratumoral applications guided by USG Doppler repeated 3 times every 21 days. CT scans before and after the treatment had been carried through, for evaluation of the tumoral response through the comparison of tumoral volume. We also did biopsis before and after the treatment, and the material was submitted the Rt-PCR in search of tranfeccion of the injected DNA. During the protocol the patients had been evalueted to rule observe adverse events that could be related to the medication. Results: Of 21 patients, seven died before the end of the protocol. In the 13 suitable for analysis, 4 partial responses and stability of the disese in 1 case had occurred. In 9 cases the tumors progressed. Two patients are still alive, with more than eight hundred days of the beginning of the protocol. The adverse events occurred mainly as an increase of local pain and edema. It was not possible to prove the transcription of the DNA injected in the Rt-PCR because of the occurrence of positive a false result. Conclusions: The application was secure in the dose of 400mcg . We saw reduction of tumoral volume in 5 of the 13 patients suitable for analysis, four partial responses and one stable disease. In the patients who had presented reduction of the tumoral volume there seems to be clinical benefit. It was not possible to prove the transfeccion of the injected DNA.

Submitted by Priscila Nascimento (pnascimento@icict.fiocruz.br) on 2012-11-21T11:40:46Z No. of bitstreams: 1 carina-cantelli-pacheco-de-oliveira.pdf: 4119562 bytes, checksum: e15daef4939ba93f9357a8bbf218d494 (MD5) / Made available in DSpace on 2012-11-21T11:40:46Z (GMT). No. of bitstreams: 1 carina-cantelli-pacheco-de-oliveira.pdf: 4119562 bytes, checksum: e15daef4939ba93f9357a8bbf218d494 (MD5) Previous issue date: 2009 / Fundação Oswaldo Cruz. Instituto de Tecnologia em Imunobiológicos. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil. / O interferon beta (IFN-β) é uma proteína globular consistindo de cinco cadeias α-helicais e como biofármaco é principalmente utilizado para o tratamento da esclerose múltipla (EM). A EM é uma doença até o momento sem cura e das terapias imunomodulatórias disponíveis para melhoria do quadro da EM, o IFN-βé o biofármaco disponível mais bem caracterizado. Duas formas do IFN-βhumano recombinante são clinicamente utilizadas: IFN-β-1a, produzida em células de ovários de hamster chinês (CHO), similar ao IFN-βnativo; e a forma IFN-β-1b, produzida em sistema de Escherichia coli, não possuindo moléculas de açúcar na cadeia polipeptídica expressa. Testes para detecção e quantificação dos IFNs são principalmente do tipo ELISA sendo cruciais nos processos de desenvolvimento, monitoramento e no controle de qualidade, devido principalmente a relação sensibilidade/especificidade necessária. Os anticorpos monoclonais (Mabs) de alta afinidade, produzidos para estes testes são extremamente sensíveis e específicos e representam uma forma adequada de padronização de um ELISA para detecção e quantificação do IFN-β. Neste estudo, quatorze MAbs anti-IFN-βforam obtidos através da imunização genética e parcialmente caracterizados. Todos reconheceram no ELISA o IFN-βhumano recombinante. Os MAbs anti-IFN-βidentificados como AE9, AG8, AE6, AH7, AA11, AB1 e AA4 foram os mais reativos. Todos os quatorze MAbs foram isotipados e apresentaram um perfil com simultânea expressão tanto de IgM quantode IgG2a. Este perfil não-usual foi confirmado pela reação em cadeia da polimerase precedida da transcrição reversa específica para IgG e IgM. Somente um MAb denominado AG8 reagiu em Western-blotcom a isoforma monomérica de 18 KDa do IFN-β. Este estudo representou o primeiro passo em direção ao propósito de obtenção do ELISA descrito acima. / Beta interferon (IFN-β) is a globular protein consisting of five α-helical chains. As biopharmaceutical product it is mainly used for treatment of multiple sclerosis (MS). MS is a health disorder with no cure available so far. Its symptoms can be alleviated with immunomodulatory drugs. IFN-βis the most well characterized biopharmaceutical product in terms of structure and side affects. Two forms of human recombinant IFN-βare used in the treatment of MS: IFN-β-1a, expressed in Chinese hamster ovary cells, is similar to native IFN-β; and IFN-β-1b expressed in the Escherichia coli expression system. IFN-β-1b does not present glycosilation and therefore differs from native IFN-β. Tests to detect and to quantify IFNs are mainly enzyme-linked immunosorbent assays (ELISA). These tests are reliable and can be used in biopharmaceutical product development processes. Monitoring and quality control of IFN-βare quite important, mainly because of the physical and chemical nature of IFN-βas well the necessary sensitivity and specificity that allow for a precise characterization of the final product. Monoclonal antibodies (MAbs) used in ELISA to detect and quantify IFN-βusually present high affinity and specificity. In this study, fourteen MAbs against human recombinant IFN-βwere obtained by genetic immunization and partially characterized. All antibodies recognized human IFN-β. The anti-IFN-βMAbs AE9, AG8, AE6, AH7, AA11, AB1 and AA4 were the most reactives. All fourteen MAbs were subjected to antibody isotype characterization and presented a simultaneous expression of both IgM and IgG2a. Thisunusual profile was confirmed by specific reverse transcription polymerase chain reaction for IgG and IgM messenger RNA. Only MAb AG8 recognized the 18 KDa isoform of IFN-β. This study represents the first step towards the development of the ELISA described above.

Introdução: O carcinoma epidermóide de cabeça e pescoço avançado é uma doença de difícil tratamento. Apesar dos avanços nas técnicas de diagnóstico e tratamento nos últimos 30 anos não ocorreram ganhos significativos em sobrevida. A falha no tratamento ocorre principalmente pela recidiva locorregional e freqüentemente impede a realização de tratamentos de resgate. Com o desenvolvimento da imunoterapia novas abordagens tem sido descritas para o combate ao câncer. Estudos em animais demonstraram a redução de tumores com a utilização de vacinas de DNA contendo a HSP-65 do Mycobacterium leprae. Neste estudo avaliou-se a utilização desta proteína em pacientes portadores de carcinoma epidermóide de cabeça e pescoço em estádio avançado e fora de possibilidades terapêutica curativa pelos métodos convencionais. Objetivos: Testar a viabilidade de realização da injeção intratumoral do DNA HSP65 nesse grupo de doentes, avaliar a resposta tumoral através da análise comparativa do volume, pesquisar a transfecção do DNA HSP65 do M. Leprae e verificar se o tratamento realizado apresentou impacto na evolução dos pacientes. Casuística e métodos: Foram incluídos 21 pacientes em três grupos. Cada grupo recebeu diferentes doses da vacina de DNA HSP-65 do Mycobacterium leprae: 150, 600 e 400µg, através de aplicações intratumorais guiadas por ultra-som com Doppler. Foram realizadas tomografias computadorizadas antes e após o tratamento, para avaliação da resposta tumoral através da comparação de volume tumoral. Realizaram-se biópsias antes e após o tratamento, e o material foi submetido a reação em cadeia da polimerase (Rt-PCR) para identificar a transfecção do DNA injetado. Durante o protocolo os pacientes foram acompanhados para observação de eventos adversos que pudessem ser relacionados à medicação. Resultados: Dos 21 pacientes, sete faleceram antes do término do protocolo. Nos 13 pacientes passíveis de análise, ocorreram quatro respostas parciais e estabilidade da lesão em um caso. Em nove casos houve progressão da doença. Dois pacientes encontram-se vivos em seguimento a mais de oitocentos dias do inicio do protocolo. Os eventos adversos ocorridos foram principalmente aumento da dor local e edema. Não foi possível comprovar a transcrição do DNA injetado no Rt-PCR pela ocorrência de um resultado falso positivo. Conclusões: A aplicação foi segura na dose de 400µg por aplicação. Não foi possível comprovar a transfecção de DNA de HSP65. Nos pacientes que apresentaram diminuição do volume tumoral parece ter havido benefício clínico. / Introduction: The squamous cell carcinoma of the head and advanced neck is an disease difficult to treat. Despite the advances in diagnosis and treatment in last the 30 years had not occurred major survival improvements. The treatment failure occurs mainly locorregionaly and recurrences frequently canot be rescued. immunotherapy has had encouraging results in the last years. Studies in animals had demonstrated the reduction of tumors with the DNA vaccine containing HSP-65 of the Mycobacterium leprae. In this study we evaluate the use of this protein in patients with avdanced head and neck carcinoma, stages II and IV without possibilities of curative treatment. Objectives: To test the viability of accomplishment of the intratumoral injection of DNA HSP65 in this group of patients, test its effectiveness through the comparative analysis of the volume, to verify transfeccion of the DNA injected and to see if the carried through treatment presented impact in the evolution of the patients. Patients and methods: 21 patients in 3 groups of doses 150,600 and 400µg of the vaccine of DNA HSP-65 of M leprae, through intratumoral applications guided by USG Doppler repeated 3 times every 21 days. CT scans before and after the treatment had been carried through, for evaluation of the tumoral response through the comparison of tumoral volume. We also did biopsis before and after the treatment, and the material was submitted the Rt-PCR in search of tranfeccion of the injected DNA. During the protocol the patients had been evalueted to rule observe adverse events that could be related to the medication. Results: Of 21 patients, seven died before the end of the protocol. In the 13 suitable for analysis, 4 partial responses and stability of the disese in 1 case had occurred. In 9 cases the tumors progressed. Two patients are still alive, with more than eight hundred days of the beginning of the protocol. The adverse events occurred mainly as an increase of local pain and edema. It was not possible to prove the transcription of the DNA injected in the Rt-PCR because of the occurrence of positive a false result. Conclusions: The application was secure in the dose of 400mcg . We saw reduction of tumoral volume in 5 of the 13 patients suitable for analysis, four partial responses and one stable disease. In the patients who had presented reduction of the tumoral volume there seems to be clinical benefit. It was not possible to prove the transfeccion of the injected DNA.

Diss. (sammanfattning) Umeå : Umeå universitet, 2010. / Härtill 4 uppsatser.

In recent years, heterologous prime-boost vaccination constructs have emerged as a promising strategy to generate broad and protective immunity against a variety of pathogens. The utility of DNA vaccination in priming the immune system, in particular, has improved the immunogenicity of vaccines against difficult pathogens such as HIV-1. In addition, many vaccine formulations include an adjuvant to augment immune responses. However, the mechanisms and profiles of many adjuvants remain largely unknown, particularly in the context of such combination immunization approaches. My thesis research studied the effects of several adjuvants, QS-21, aluminum hydroxide, MPL, and ISCOMATRIX™ adjuvant in the context of a previously described pentavalent HIV-1 Env DNA prime-protein boost vaccine, DP6-001. In a murine model, we quantified HIV antigen-specific humoral and T cell responses, as well as pro-inflammatory serum cytokine and chemokines, both shortly after immunization and at the termination of studies. Our data indicates that each candidate adjuvant generates a unique pattern of biomarkers as well as improved immunogenicity in the context of the DP6-001 DNA prime-protein boost vaccine. Additionally, we examined the impact of several innate signaling pathways on the adaptive immunity raised by DP6-001 and adjuvants, as well as on the unique serum cytokine profiles. These studies provide valuable information in selection of an adjuvant for inclusion in future prime-boost strategies, with the goal of enhancing immunogenicity while minimizing reactogenicity. Furthermore, these studies provided insight about the utility of different current adjuvants in a prime-boost formulation, and the unique immune environment induced by DNA priming.

Despite 30 years of intensive research，an effective human immunodeficiency virus (HIV) vaccine still remains elusive. The desirable immune response capable of providing protection against HIV acquisition is still not clear. The accumulating evidence learned from a recent vaccine efficacy correlate study not only confirmed the importance of antibody responses, but also highlighted potential protective functions of antibodies with a broad repertoire of HIV-1 epitope specificities and a wide range of different antiviral mechanisms. This necessitates a deep understanding of the complexity and diversity of antibody responses elicited by HIV-1 vaccines. My dissertation characterizes antibody response profiles of HIV-1 Env antibodies elicited by several novel immunogens or different immunization regimens, in terms of magnitude, persistence, epitope specificity, binding affinity, and biological function. First, to overcome the challenge of studying polyclonal sera without established assays, we expanded a novel platform to isolate Env-specific Rabbit mAbs (RmAb) elicited by DNA prime-protein boost immunization. These RmAbs revealed diverse epitope specificity and cross-reactivity against multiple gp120 antigens from more than one subtype, and several had potent and broad neutralizing activities against sensitive Tier 1 viruses. Further, structural analysis of two V3 mAbs demonstrated that a slight shift of the V3 epitope might have a dramatic impact on their neutralization activity. All of these observations provide a useful tool to study the induction of a desired type of antibody by different immunogens or different immunization regimens. Since heavily glycosylated HIV Env protein is a critical component of an HIV vaccine, we wanted to determine the impact of the HIV Env-associated glycan shield on antibody responses. We were able to produce Env proteins with a selective and homogeneous pattern of N-glycosylation using a glycoengineered yeast cell line. Antigenicity of these novel Env proteins was examined by well-characterized human mAbs. Immunogenicity studies showed that they were immunogenic and elicited gp120- specific antibody responses. More significantly, sera elicited by glycan-modified gp120 protein immunogens revealed better neutralizing activities and increased diversity of epitopes compared to sera elicited by traditional gp120 produced in Chinese Hamster Ovary (CHO) cells. Further, we examined the impact of the delivery order of DNA and protein immunization on antibody responses. We found that DNA prime-protein boost induced a comparable level of Env-specific binding Abs at the peak immunogenicity point to codelivery of DNA. However, antibody responses from DNA prime-protein boost had high avidity and diverse specificities, which improved potency and breadth of neutralizing Abs against Tier 1 viruses. Our data indicate that DNA vaccine priming of the immune system is essential for generation of high-quality antibodies. Additionally, we determined the relative immunogenicity of gp120 and gp160 Env in the context of DNA prime-protein boost vaccination to induce high-quality antibody responses. Immunized sera from gp120 DNA primed animals, but not those primed with gp160 DNA, presented with distinct antibody repertoire specificities, a high magnitude of CD4 binding site-directed binding capabilities as well as neutralizing activities. We confirmed the importance of using the gp120 Env form at the DNA priming phase, which directly determined the quality of antibody response.

A formulação HIVBr18, previamente desenvolvida e testada, é uma vacina de DNA que codifica 18 epítopos CD4, promíscuos e conservados do HIV-1, e que após imunização de camundongos transgênicos para diversas moléculas de HLA de classe II humanas, observou-se proliferação de linfócitos T CD4+ e CD8+ e produção de IFN-? direcionadas a múltiplos epítopos codificados pela vacina. Abordamos aqui estratégias baseadas na fusão ou combinação dos epítopos codificados pela vacina HIVBr18 à glicoproteína D (gD) do HSV-1, e também na coadministração de plasmídeos que codificam citocinas (IL-2, -12, -15 e GM-CSF) visando aumentar a imunogenicidade de HIVBr18. A sequencia de DNA que codifica os 18 peptídeos da vacina HIVBr18 foi amplificada por PCR e clonada em um plasmídeo que abrigava a sequencia da gD do HSV-1. dando origem ao plasmídeo pVAX-gDh-HIVBr18. Animais imunizados com gDh-HIVBr18 apresentaram resposta imunológica similar ao grupo que recebeu somente HIVBr18, não sendo diferente também daqueles que receberam plasmídeos gDh-HIVBr18 que sofreram alterações nas sequências para melhorar o padrão de distribuição hidrofóbica e permitir a migração da proteína de fusão para o meio extracelular. Construímos e testamos um plasmídeo bicistrônico que expressa gDh e HIVBr18 isoladamente, mas também não observamos aumento na resposta imune induzida. A coadministração com o plasmídeo HIVBr18 e plasmídeos que codificam as citocinas IL-12, IL-15 e GM-CSF, proporciona um aumento na magnitude da resposta imunológica induzida contra o pool de peptídeos codificados pela vacina, entretanto sem alteração da amplitude da resposta. Além disso, o plasmídeo de GM-CSF induziu maior número de células T CD4+ polifuncionais. Demonstramos também que a coadministração do plasmídeo que codifica GM-CSF, induz uma resposta imune celular de maior magnitude mesmo em uma condição de dose reduzida. Entretanto, observamos que esta citocina não é um bom adjuvante quando utilizamos como vetor de imunização um adenovírus que expressa os 18 epítopos / The formulation HIVBr18, previously developed and tested, is based on a DNA vaccine encoding 18 conserved and promiscuous HIV-1 CD4 epitopes and after immunization of transgenic mice for many human HLA class II molecules using this DNA vaccine, could be observed proliferation of CD4+ and CD8+ T cells and IFN-y production directed to multiple epitopes encoded by the vaccine. We intend to explore here, strategies based on fusion or combination of epitopes encoded by HIVBr18 vaccine with glycoprotein D (gD) of HSV- 1 and also the coadministration of cytokine-encoding plasmids (pIL-2, -12, -15 and pGM -CSF) aiming to enhance immunogenicity of HIVBr18. The DNA sequence of epitopes encoded by HIVBr18 vaccine was amplified by PCR and cloned into a plasmid that contained the sequence of gD, giving rise to plasmid pVAX-gDh-HIVBr18. After mice immunization, animals immunized with this construct showed similar immune response to the group that received HIVBr18, and also the group of animals that received gDh-HIVBr18 plasmid that had been modified by exchange in peptides order to assure to the molecule a better hydrophobic distribution and allow translocation to the extracellular face of cell membrane. We constructed and injected mice with a bicistronic plasmid expressing gDh and HIVBr18, simultaneously and isolated, but no increase in the magnitude of the immune response was observed. HIVBr18 coadministration with cytokine-encoding plasmids pIL-12, pIL-15 and pGM-CSF, provides an increase in the magnitude of immune response induced against the peptides encoded by the vaccine, and similar breadth. In addition, co-immunization with pGM-CSF induced greater number of polyfunctional CD4 + T cells. We also demonstrate that, even in a low dose approach coadministration of pGM-CSF induced a higher immune response than HIVBr18 alone in the same dose. However, we observed that this cytokine is not a good adjuvant when used in combination with an adenovirus that expresses the 18 HIV-1 epitopes.

Abordagens atuais no desenho de vacinas contra o HIV-1 estão focadas em imunógenos que codificam proteínas inteiras do HIV-1 e visam induzir respostas citotóxicas específicas. É concebível que vacinas bem-sucedidas devem induzir respostas contra múltiplos epitopos do HIV-1, coincidindo com seqüências das cepas circulantes do vírus, conhecido por sua grande variabilidade genética. Sabe-se que células T CD4+ são necessárias para indução de respostas efetivas de linfócitos T CD8+ citotóxicos. Neste trabalho, nós avaliamos a imunogenicidade de uma vacina de DNA codificando 18 epitopos para linfócitos T CD4+, conservados e ligadores de múltiplas moléculas HLA-DR em camundongos BALB/c e em quatro linhagens de camundongos transgênicos para moléculas de HLA classe II. Os camundongos imunizados apresentaram respostas de amplitude e magnitude significativas com proliferação e secreção de citocinas por linfócitos T CD4+ e T CD8+. Onze dos 18 epitopos para linfócitos T CD4+ presentes na vacina foram reconhecidos pelas linhagens de camundongos transgênicos para moléculas de HLA classe II. Em suma, 17 dos 18 epitopos codificados pela vacina foram reconhecidos. As células induzidas pela vacina apresentaram um perfil polifuncional com tipo 1 de citocinas, incluindo produção de IFN- , TNF- e IL-2. A vacina também induziu células T CD4+ de memória central de longa duração, capazes de fornecer auxílio contínuo para células T CD8 +. Pela capacidade da vacina HIVBr18 de induzir respostas contra múltiplos epitopos de linfócitos T CD4+ conservados que podem ser reconhecidos no contexto de múltiplas moléculas de HLA classe II, esse conceito vacinal pode solucionar o problema da variabilidade genética viral assim como aumentar a cobertura populacional. Portanto, essa vacina, pode ser útil se utilizada isoladamente ou como fonte de auxílio cognato para células T CD8+ HIV-específicas induzidas por outros imunógenos gerando resposta em uma grande proporção dos vacinados / Current HIV vaccine approaches are focused on immunogens encoding whole HIV antigenic proteins that elicit cytotoxic CD8+ responses. It is conceivable that successful vaccines have to elicit responses to multiple epitopes, to match circulating strains of HIV, a virus known for its high genetic variability. It is known that CD4+ T cell responses are necessary for effective CD8+ antiviral responses. Here we assessed the immunogenicity of a DNA vaccine encoding 18 conserved, multiple HLA-DR-binding HIV CD4 epitopes in BALB/c and four strains of HLA class II-transgenic mice. Immunized mice displayed CD4+ and CD8+ proliferative and cytokine T cell responses of significant breadth and magnitude. Eleven out of the 18 encoded epitopes were recognized by CD4+ T cells from HLA class IItransgenic strain. Overall, 17 out of the 18 encoded peptides were recognized. The induced T cell response had a polyfunctional type 1 cytokine profile, including IFN- , TNF- and IL-2. The vaccine also induced long-lived central memory CD4+ T cells, which might provide sustained help for CD8+ T cells. By virtue of inducing broad responses against conserved CD4+ T cell epitopes that can be recognized in the context of widely diverse, common HLA class II alleles, this vaccine concept may cope both with HIV genetic variability and increased population coverage. The vaccine may thus be usefull either as a standalone approach or as a source of cognate help for HIV-specific CD8+ T cells elicited by conventional immunogens, eliciting responses in a wide proportion of vaccinees

A formulação HIVBr18, previamente desenvolvida e testada, é uma vacina de DNA que codifica 18 epítopos CD4, promíscuos e conservados do HIV-1, e que após imunização de camundongos transgênicos para diversas moléculas de HLA de classe II humanas, observou-se proliferação de linfócitos T CD4+ e CD8+ e produção de IFN-? direcionadas a múltiplos epítopos codificados pela vacina. Abordamos aqui estratégias baseadas na fusão ou combinação dos epítopos codificados pela vacina HIVBr18 à glicoproteína D (gD) do HSV-1, e também na coadministração de plasmídeos que codificam citocinas (IL-2, -12, -15 e GM-CSF) visando aumentar a imunogenicidade de HIVBr18. A sequencia de DNA que codifica os 18 peptídeos da vacina HIVBr18 foi amplificada por PCR e clonada em um plasmídeo que abrigava a sequencia da gD do HSV-1. dando origem ao plasmídeo pVAX-gDh-HIVBr18. Animais imunizados com gDh-HIVBr18 apresentaram resposta imunológica similar ao grupo que recebeu somente HIVBr18, não sendo diferente também daqueles que receberam plasmídeos gDh-HIVBr18 que sofreram alterações nas sequências para melhorar o padrão de distribuição hidrofóbica e permitir a migração da proteína de fusão para o meio extracelular. Construímos e testamos um plasmídeo bicistrônico que expressa gDh e HIVBr18 isoladamente, mas também não observamos aumento na resposta imune induzida. A coadministração com o plasmídeo HIVBr18 e plasmídeos que codificam as citocinas IL-12, IL-15 e GM-CSF, proporciona um aumento na magnitude da resposta imunológica induzida contra o pool de peptídeos codificados pela vacina, entretanto sem alteração da amplitude da resposta. Além disso, o plasmídeo de GM-CSF induziu maior número de células T CD4+ polifuncionais. Demonstramos também que a coadministração do plasmídeo que codifica GM-CSF, induz uma resposta imune celular de maior magnitude mesmo em uma condição de dose reduzida. Entretanto, observamos que esta citocina não é um bom adjuvante quando utilizamos como vetor de imunização um adenovírus que expressa os 18 epítopos / The formulation HIVBr18, previously developed and tested, is based on a DNA vaccine encoding 18 conserved and promiscuous HIV-1 CD4 epitopes and after immunization of transgenic mice for many human HLA class II molecules using this DNA vaccine, could be observed proliferation of CD4+ and CD8+ T cells and IFN-y production directed to multiple epitopes encoded by the vaccine. We intend to explore here, strategies based on fusion or combination of epitopes encoded by HIVBr18 vaccine with glycoprotein D (gD) of HSV- 1 and also the coadministration of cytokine-encoding plasmids (pIL-2, -12, -15 and pGM -CSF) aiming to enhance immunogenicity of HIVBr18. The DNA sequence of epitopes encoded by HIVBr18 vaccine was amplified by PCR and cloned into a plasmid that contained the sequence of gD, giving rise to plasmid pVAX-gDh-HIVBr18. After mice immunization, animals immunized with this construct showed similar immune response to the group that received HIVBr18, and also the group of animals that received gDh-HIVBr18 plasmid that had been modified by exchange in peptides order to assure to the molecule a better hydrophobic distribution and allow translocation to the extracellular face of cell membrane. We constructed and injected mice with a bicistronic plasmid expressing gDh and HIVBr18, simultaneously and isolated, but no increase in the magnitude of the immune response was observed. HIVBr18 coadministration with cytokine-encoding plasmids pIL-12, pIL-15 and pGM-CSF, provides an increase in the magnitude of immune response induced against the peptides encoded by the vaccine, and similar breadth. In addition, co-immunization with pGM-CSF induced greater number of polyfunctional CD4 + T cells. We also demonstrate that, even in a low dose approach coadministration of pGM-CSF induced a higher immune response than HIVBr18 alone in the same dose. However, we observed that this cytokine is not a good adjuvant when used in combination with an adenovirus that expresses the 18 HIV-1 epitopes.