Influência da vacinação materna na transferência de imunidade passiva contra as viroses respiratórias dos bovinos / Influence of maternal vaccination for the passive immune transfer against bovine respiratory viruses

O objetivo deste estudo longitudinal foi avaliar a influência da vacinação materna na transferência de anticorpos (ACs) contra as viroses respiratórias em bezerros. Para tanto, vacas e bezerros foram distribuídos em dois grupos conforme a realização (VAC, n=6) ou não (NVAC, n=4) da vacinação no pré-parto. Amostras sanguíneas foram obtidas após a parição (D0); em seguida, apenas os bezerros foram acompanhados até D180. ACs séricos foram determinados pela vírus-neutralização (VN) contra BVDV, BoHV-1, BRSV e BPI3-V. Vacas VAC apresentaram diferenças para ACs contra BoHV-1 (P=0,01) em D0. As frequências (%) de bezerros soropositivos para BoHV-1 foram maiores em VAC do D2 ao D120; para BRSV em D4, D8, D10 e D150 (P≤0,08); medianas de ACs contra BoHV-1 em VAC do D2 ao D120 (P=0,08). A vacinação das vacas no pré-parto foi fundamental para a transferência e a duração de ACs contra BoHV-1 e BRSV, porém o protocolo adotado não foi eficiente para o aumento de ACs para BVDV e BPI3-V. A eficácia parcial da vacinação materna não inviabiliza a sua recomendação devido à importância do Herpesvírus e do BRSV na DRB, porém estratégias para a melhoria nas respostas imunes contra as demais viroses devem ser estabelecidas.(AU)

The aim of this longitudinal research was to evaluate the influence of maternal vaccination for the passive immune transfer of antibodies (Abs) against respiratory viruses in calves. Therefore, cows and calves sourced from two groups according to having received (VAC, n=6) or not (NVAC, n=4) of vaccination at pre-partum period. Blood samples of cows and calves harvested after parturition (D0), and then only calves followed until the age of 180 days. Abs performed by virus neutralization (VN) against BVDV, BoHV-1, BRSV and BPI3-V. VAC cows presented differences for Abs against BoHV-1 (P=0.01) in D0. Frequencies (%) of seropositive VAC calves for BoHV-1 were higher in D2 to D120; to BRSV D4, D8, D10 and D150 (P≤0.08); higher medians of Abs against BoHV-1 in VAC at D2 up to D120 (P=0.08). Partial efficacy of vaccination of cows does not impair its recommendation due to the importance of Herpesvirus and BRSV in BRD, but strategies for improvement in immune responses against other viruses should be established.(AU)

Transferência de imunidade passiva (TIP) e dinâmica de anticorpos específicos em bezerros naturalmente expostos para as viroses respiratórias / Passive immune transfer (PIT) and dynamics of specific antibodies in calves naturally exposed to the respiratory viruses

Esta pesquisa avaliou a TIP e a dinâmica de anticorpos (ACs) específicos em bezerros naturalmente expostos aos agentes causadores da doença respiratória bovina (DRB). Foram selecionados 19 bezerros Holandeses alimentados com colostro proveniente de doadoras vacinadas para DRB. Amostras de soro foram obtidas antes e após a ingestão do colostro (48h) para a soroneutralização (SN). Os valores médios (log2) detectados após colostragem foram de 11,5±1,6 (BVDV), 8,8±1,3 (BoHV-1), 5,5±1,6 (BRSV) e 8,4±1,5 (BPIV-3). Cinco bezerros foram criados do nascimento aos 240 dias de vida, observando-se decréscimo nos títulos de ACs para BVDV, BoHV-1 e BPIV-3 ao longo do tempo (P≤0,001). As taxas de infecções detectadas entre o D14 e o D240 foram de 40% (2/5), 20% (1/5), 80% (4/5), e 60% (3/5), respectivamente, para BVDV, BoHV-1, BRSV e BPIV-3. A maioria dos bezerros manifestou broncopneumonia após as infecções virais. Os bezerros apresentaram ACs para todas as viroses às 48 horas de vida, porém os títulos adquiridos para o BRSV foram baixos. A susceptibilidade para as infecções variou de acordo com os níveis e a duração dos títulos de ACs maternos.(AU)

This research evaluated the PIT and the dynamics of specific antibody (Ab) for calves naturally exposed to the viral agents involved in Bovine Respiratory Disease (BRD). Nineteen Holstein calves fed colostrum from vaccinated donors for DRB. Serum samples were obtained before and after colostrum intake (48h) for serum neutralization (SN). Mean values (log2) detected after colostrum feeding were 11.5±1.6 (BVDV), 8.8 ±1.3 (BoHV-1) 5.5±1.6 (BRSV) and 8.4±1.5 (BPIV-3). Five calves were raised from birth to 240 days of life and presented a decrease in Ab titers for BVDV, BoHV-1 and BPIV-3 over time (P≤ 0.001). Infection rates from D14 to D240 were of 40% (2/5), 20% (1/5), 80% (4/5) and 60% (3/5), respectively for BVDV, BoHV-1, BRSV and BPIV-3. Most of the calves presented bronchopneumonia after seroconversion to the virus. Calves presented Ab for all viruses at 48 hours of life, however BRSV Ab titer were low. Levels and persistence of maternal antibody titers determined the susceptibility to viral infections.(AU)

Commentory on “LIVE, ORALLY GIVEN POLIOVIRUS VACCINE - EFFECTS OF RAPID MASS IMMUNIZATION IN POPULATION UNDER CONDITIONS OF MASSIVE ENTERIC INFECTION WITH OTHER VIRUSES.

The following is a commentary on the article “Sabin AB, Ramos-Alvarez M, Alvarez-Amezquita J, Pelon W, Michaels RH, Spigland I, et al. Live, orally given poliovirus vaccine: effects of rapid mass immunization on population under conditions of massive enteric infection with other viruses. Jama. 1960;173(14):1521-6.” Abstract (of the original article): The phenomenon of viral interference must be taken into account in planning the use of live poliovirus vaccine in areas where conditions favor the extensive dissemination of naturally occurring polioviruses. Experience with feeding a trivalent vaccine to 26,033 children in a tropical city of 100, 000 population led to the conclusion that interference was overcome by mass feeding of vaccine to 86% of all children under 11 years within a period of about four days, and that, because dissemination of the poliovirus was self-limited, a second feeding of trivalent vaccine was necessary to achieve immunization of almost all children. Recom-mendations are here formulated for the eradication of poliomyelitis, but they apply only to subtropical and tropical regions with extensive dissemination of various enteric viruses and not to temperate zones with good sanitation and hygiene during certain periods of the year and under conditions of low or absent dis-semination of enteric viruses.

Papel de los receptores tipo toll (TLRs) y receptores para dominios de oligomerización para la unión a nucleótidos (NLRs) en las infecciones virales / Role of toll-like receptors (TLRs) and nucleotide-binding oligomerization domain receptors (NLRs) in viral infections

Las células del sistema inmunitario (SI) son capaces de reconocer una gran variedad de microorganismos, a través de los receptores que se encuentran expresados y distribuidos a lo largo de su arquitectura celular. La interacción entre los patrones moleculares asociados a microorganismos o a daño (PMAM o PMAD) y los receptores reconocedores de patrones (RRP) presentes en las células del hospedero es un evento crítico que implica procesos intracelulares de señalización que finalizan en la expresión de mediadores tanto proinflamatorios como antivirales. Por consiguiente, de la integridad de estos receptores dependerá el buen funcionamiento de los distintos mecanismos de transducción de señal desde las membranas celulares al citoplasma y por ende, de la respuesta que el SI desencadene contra los patógenos entre ellos los agentes virales. De allí que, en esta revisión se discutirá el papel de los receptores tipo toll (TLRs) y receptores para dominios de oligomerización para la unión a nucleótidos (NLRs) en las infecciones virales, tomando como evidencia los estudios en humanos y ratones que a la fecha se conocen.

The immune system (IS) cells are capable of recognizing a wide variety of microorganisms, through receptors that are expressed and distributed throughout the cell architecture. The interaction between the pathogen-associated molecular patterns or damage-associated molecular patterns (PAMPs or DAMPs) and pattern recognition receptors (PRR), present in host cells, is a critical event that involves intracellular signaling processes that end up in the expression of both, proinflammatory and antiviral mediators. Accordingly, the proper functioning of the different mechanisms of signal transduction from the cell membrane to the cytoplasm will depend on the integrity of these receptors (PRR); and therefore, the IS response triggered against pathogens including viral agents. Hence, in this review we discuss the role of toll-like receptors (TLRs) and nucleotide-binding oligomerization domain receptors (NLRs) in viral infections, using as evidence the studies in humans and mice known to date.

Variaciones en el número y función de los linfocitos asesinos naturales durante infecciones recurrentes o graves / Variation in NK cell number and function in individuals with recurrent or severe infections

Introducción. Existen pocos datos sobre los defectos que afectan el desarrollo y función de los linfocitos asesinos naturales ( natural killers, NK) en pacientes con un incremento anormal en la recurrencia de infecciones. Objetivo. Realizar una evaluación sistemática de las diferentes subpoblaciones y la función de estas células en pacientes con infecciones recurrentes. Materiales y métodos. Se incluyeron 20 pacientes con infecciones graves o recurrentes y se analizaron las subpoblaciones y la respuesta citotóxica de los linfocitos NK en sangre periférica. Los resultados de los pacientes se compararon con controles sanos pareados por edad y sexo. Resultados. Los pacientes con episodios infecciosos activos presentaron anormalidades transitorias en el porcentaje o el número absoluto de linfocitos NK. Se caracterizaron, además, cinco pacientes con alteraciones persistentes en la distribución de las subpoblaciones de linfocitos NK. Estas alteraciones se debieron principalmente a la disminución de células CD56 dim CD16 bright . Se evidenciaron, también, defectos en la función de los linfocitos NK en algunos de nuestros pacientes; sin embargo, estas alteraciones fueron transitorias y se asociaron principalmente a la fase activa de la enfermedad. Conclusiones. Nuestros resultados evidencian defectos transitorios en el número y función de los linfocitos NK en pacientes con infecciones recurrentes o graves, además de alteraciones persistentes en los LNK CD56 dim CD16 bright en algunos individuos. Es necesario profundizar en los mecanismos que conllevan al desarrollo de estos defectos inmunes y estudiar cómo estas alteraciones influyen en la respuesta inmune.

Introduction: The information about defects affecting natural killer cell (NK) development and activity in patients with an abnormal increase of recurrent infections is scarce. Objective: To perform a systematic analysis of NK abnormalities in patients with recurrent infections. Materials and methods: Our study enrolled twenty patients with severe or recurrent viral infections. Natural killer cell subsets, surface receptors expression and cytotoxicity were analyzed. Results were compared with those from age- and sex-matched healthy controls. Results: Transient alterations were observed in the percentages and absolute numbers of NK cells in patients with infection active episodes. We also described five patients with stable disturbances in the distribution of NK cell subpopulations. These defects are mainly due to a decrease in the CD56 dim CD16 bright cells in peripheral blood. In addition, NK cell function abnormalities were observed in some patients, however, those were always transient and mainly associated to active disease. Conclusions: These findings demonstrate transient alterations in the percentages and absolute numbers of NK cells in patients with recurrent or severe infection. Also, stable disturbances in CD56 dim CD16 bright NK cells are observed in these patients. Nevertheless, these parameters must be thoroughly studied to determine the mechanisms that entail these immune abnormalities and investigate how they alter the immune response.

HTLV em gestantes de dois municípios da região sul da Bahia e avaliação da transmissão materno-infantil / HTLV in pregnant women in two cities of southern Bahia and evaluation of maternal-infant transmission

A prevalência de HTLV- 1 no Brasil é diversa, dependendo tanto da região geográfica quanto do grupo analisado. Um estudo populacional realizado em Salvador detectou prevalência de 1,76%, além de maior prevalência em mulheres e associação com menores níveis de escolaridade e renda. Como a via mais frequente de transmissão vertical do HTLV-1 é a amamentação e considerando a maior prevalência nas mulheres, é muito importante a realização de exames de triagem para HTLV-1 como parte do prénatal. Até o momento, não existem estudos publicados sobre a soroprevalência do HTLV-1 em gestantes na região sul da Bahia. No presente estudo, as gestantes foram selecionadas em dois centros de referência regionais de saúde do sul da Bahia. Um total de 2.766 gestantes atendidas na sala de pré-parto entre novembro de 2008 e maio de 2010 foram analisados. Um questionário foi aplicado, e todas as amostras de plasma reagentes foram testadas em duplicata e confirmadas por Western blot e PCR. Além disso, mulheres positivas foram contactadas e visitadas. Os membros da família que estavam presentes durante a visita foram convidados a serem testados para o HTLV...

The prevalence of HTLV-1 in Brazil is diverse, depending on both the geographic region and the group analyzed. A study conducted on general population revealed that the prevalence in Salvador was 1.76%. Besides, it was also found that the prevalence was higher amongst women and that the virus was associated with lower education and lower income. As the most frequent pathway of vertical transmission of HTLV-1 is breast-feeding, and considering the higher prevalence in women, it is very important to perform screening examinations for anti-HTLV-1...

Use of minocycline in viral infections.

Repurposing of old drugs is a useful concept as it helps to minimize costs associated with the research and development of a new drug. Minocycline, a common second generation antibiotic, has been shown to possess several other beneficial effects other than its intended uses. The antiviral role of minocycline has generated considerable interest from the last decade. It was first shown to be beneficial in preventing human immunodeficiency virus (HIV) infections and later it was reported to improve cognitive deficiencies associate with neuroAIDS. However, its antiviral efficacies are not limited to retroviruses alone. In animal models or in vitro systems of flaviviral infections (especially Japanese encephalitis virus), minocycline has been shown to be highly effective. However, not all effects are based on direct inhibition of viral replication. The general anti-inflammatory and immunomodulatory properties of minocycline are also responsible in part, in imparting the protective effects. Owing to the fact that minocycline is well tolerated by most people and that the drug has nearly 40 years history of usage, it is an exciting prospect to try out in other viral infections.

Viral infections detected by serology and PCR of perilymphatic fluid in children with idiopathic sensorineural hearing loss

The etiology of sensorineural hearing loss [SNHL] in children may be viral. This cross-sectional study aimed to determine the role of viral infectious agents in children with idiopathic SNHL Of 119 children with SNHL aged 3-168 months undergoing cochlear implant surgery at a hospital in Tehran, no cause could be established in 18 cases [15.1%]. Cytomegalovirus [CMV] and herpes simplex virus [HSV] active infections [detected by DNA-PCR, confirmed by serology] were found in the perilymphatic fluid of 16.7% [3/18] cases of idiopathic SNHL Serology was performed on blood samples from 11 of these cases: specific antibodies against CMV, Toxoplasmo spp., HSV and rubella were determined in all cases; acute T. gondii infection was detected in 7 cases and rubella IgG was found in only 1 case. Neonatal screening for CMV, HSV and T. gondii may be helpful in the Islamic Republic of Iran

Intrinsic Cellular Defenses against Virus Infection by Antiviral Type I Interferon

Intrinsic cellular defenses are non-specific antiviral activities by recognizing pathogen-associated molecular patterns (PAMPs). Toll-like receptors (TLRs), one of the pathogen recognize receptor (PRR), sense various microbial ligands. Especially, TLR2, TLR3, TLR4, TLR7, TLR8 and TLR9 recognize viral ligands such as glycoprotein, single- or double-stranded RNA and CpG nucleotides. The binding of viral ligands to TLRs transmits its signal to Toll/interleukin-1 receptor (TIR) to activate transcription factors via signal transduction pathway. Through activation of transcription factors, such as interferon regulatory factor-3, 5, and 7 (IRF-3, 5, 7) or nuclear factor-kappaB (NF-kappaB), type I interferons are induced, and antiviral proteins such as myxovirus-resistance protein (Mx) GTPase, RNA-dependent Protein Kinase (PKR), ribonuclease L (RNase L), Oligo-adenylate Synthetase (OAS) and Interferon Stimulated Gene (ISG) are further expressed. These antiviral proteins play an important role of antiviral resistancy against several viral pathogens in infected cells and further activate innate immune responses.

Relationship among epidemiological parameters of six childhood infections in a non-immunized Brazilian community

Epidemiological parameters, such as age-dependent force of infection and average age at infection () were estimated for rubella, varicella, rotavirus A, respiratory syncytial virus, hepatitis A and parvovirus B19 infections for a non-immunized Brazilian community, using the same sera samples. The for the aforementioned diseases were 8.45 years (yr) [95 percent CI: (7.23, 9.48) yr], 3.90 yr [95 percent CI: (3.51, 4.28) yr], 1.03 yr [95 percent CI: (0.96, 1.09) yr], 1.58 yr [95 percent CI: (1.39, 1.79) yr], 7.17 yr [95 percent CI: (6.48, 7.80) yr] and 7.43 yr [95 percent CI: (5.68, 9.59) yr], respectively. The differences between average ages could be explained by factors such as differences in the effectiveness of the protection conferred to newborns by maternally derived antibodies, competition between virus species and age-dependent host susceptibility. Our seroprevalence data may illustrate a case of the above-mentioned mechanisms working together within the same population.

Consensus recommendations on immunization, 2008.

JUSTIFICATION: There is a need to formulate recommendations regarding use of new vaccines which have become recently available/will soon be available and to review/revise recommendations about existing vaccines in light of recent information. PROCESS: Following an IAPCOI meeting in March 2008, a draft statement was prepared and circulated among the meeting participants to arrive at a consensus. OBJECTIVES: To formulate recommendations pertaining to use of Tdap, human papilloma virus (HPV) vaccines and rotavirus vaccines and to revise recommendations pertaining to use of pneumococcal and inactivated poliovirus vaccines (IPV). These recommendations are primarily for pediatricians in office practice. RECOMMENDATIONS: IAP COI recommends (i) offering Tdap vaccine instead of Td/TT vaccine to all children/ adolescents who can afford to use the vaccine at the age of 10-12 yrs; (ii) offering HPV vaccine to all females who can afford the vaccine at the age of 10-12 years; (iii) offering both seven valent pneumococcal conjugate vaccine (PCV 7) and 23 valent pneumococcal polysaccharide vaccine (PPV 23) in all high risk children who can afford the vaccine; (iv) offering IPV in addition to oral poliovirus vaccine (OPV) in all children who can afford the vaccine at the age of 6, 10, 14 weeks and a booster at 15-18 months; (v) the use of oral rotavirus vaccines after one-to-one discussion with parents beginning age 6 weeks; and (iv) the use of PCV 7 in healthy children aged below 2 years after one-to-one discussion with parents at the age of 6, 10, 14 weeks and booster at 15-18 months.

Disease associations of mannose-binding lectin & potential of replacement therapy.

Mannose-binding lectin (MBL) is an important component of the immune defence able to bind to repeating mannose based structural patterns typical of microbial surface (bacteria, viruses, fungi, parasites) leading to opsonization and phagocytosis, and activation of the complement pathway resulting in lysis of the pathogen. MBL thus plays a very important role in the first line of host immune response. MBL deficiency has been implicated in susceptibility and modulating the severity in viral, bacterial, fungal, and protozoan infections. High MBL levels, on the contrary might be helpful to intracellular organisms, which take the advantage of C3 opsonization and C3 receptor on monocytes/macrophages to enter their host. MBL replacement therapy to help patients with MBL deficiency has undergone phase I clinical trials. Phase II and III trials and production of recombinant MBL for replacement therapy are currently underway.

Papel de los receptores tipo toll en las infecciones virales: el VIH-1 como modelo / The role of toll-like receptors in viral infections: HIV-1 as a model

Los receptores tipo toll son un componente esencial de la respuesta inmune innata y adaptativa, pues se encargan del reconocimiento de los diferentes agentes patógenos y desencadenan respuestas dirigidas a eliminarlos y a desarrollar memoria inmunológica. Durante las infecciones virales se activan diferentes receptores tipo toll que, generalmente, inducen una respuesta inmune protectora pero, también, pueden hacer parte de los mecanismos patogénicos del virus. Una de las infecciones virales en la que los receptores tipo toll participan de esta respuesta dual, es la infección por el VIH-1, en la cual varios de estos receptores se activan para desarrollar respuestas antivirales dirigidas por los interferones tipo 1; pero, la replicación y la diseminación del virus también se favorecen por las señales derivadas de la estimulación de dichos receptores, en particular, por las infecciones asociadas con microorganismos oportunistas, lo cual favorece la progresión de la infección por el VIH-1. Un entendimiento integral del comportamiento de estos receptores durante las infecciones virales, permitirá diseñar estrategias profilácticas o terapéuticas basadas en la modulación de su expresión y función, en particular, utilizando agonistas de estos receptores que sean eficaces en la lucha por el control de las infecciones virales.

The toll-like receptors are an essential component of the innate and adaptive immune response. They are responsible for the recognition of different pathogens agents and trigger responses directed at eliminating the pathogens as well as the development of immunological long-term memory. During viral infections, several different toll-like receptors are activated. These generally induce a protective immune response, but at the same time, can also be part of the pathogenic mechanisms of the viral infection. One of the viral infections in which toll-like receptors participate is the HIV-1 infection. Here, several receptors are activated to develop antiviral responses mediated by interferon type I; however virus replication and spreading dissemination are also favoured by signals derived from stimulation of the toll-like receptors. Individuals co-infected with opportunistic microorganisms are particularly affected, promoting the progression of HIV- 1 infection. An integral understanding of the behavior of toll-like receptors during viral infections will allow the design of prophylactic and/or therapeutic strategies, based on the modulation of the expression and function of these receptors. Agonists of these receptors can be used effectively to control these viral infections.

Vacinação em situações especiais / Vaccination in special situations

OBJETIVOS: Revisar a indicação, contra-indicação e eficácia da vacinação em algumas situações especiais: imunossupressão, prematuridade, gestação e pós-exposição. FONTES DOS DADOS: Revisão sistemática dos artigos sobre o tema publicado nas 2 últimas décadas pesquisados nas bases de dados MEDLINE, SciELO e Lilacs. Consulta às normas do Programa Nacional de Imunização, Brasil, 2001 a 2004, e normas do Programa Nacional de DST/AIDS, Brasil, 2004. Consulta aos temas livres publicados em anais de congressos internacionais e nacionais de pediatria e doenças infecciosas, nos últimos 5 anos. SíNTESE DOS DADOS: Algumas situações especiais, como imunossupressão, prematuridade, gestação e exposição às doenças infecciosas, colocam os indivíduos em maior risco de adoecer ou apresentar eventos adversos pós-vacinais. Essas situações requerem esquemas vacinais diferenciados, podem indicar adiamento da vacinação e mesmo contra-indicá-la. De modo geral, as vacinas inativadas, ou de toxóides, podem ser aplicadas, levando-se sempre em consideração a possibilidade de resposta imunogênica insuficiente. Para indivíduos imunossuprimidos, as vacinas de vírus e bactérias vivos devem ser evitadas devido ao risco de disseminação do agente vacinal. O cuidado na imunização deve incluir não só o paciente, mas seus contatos no domicílio, creche, etc. CONCLUSÕES: Esquemas adequados para cada uma dessas situações aumentam a possibilidade de obter melhor proteção vacinal e diminuem o risco de eventos adversos indesejáveis. Após exposição às doenças infecciosas, indivíduos imunodeficientes ou imunossuprimidos que não tiveram os títulos de anticorpos pós-vacinais avaliados devem ser considerados não protegidos, e medidas profiláticas disponíveis, incluindo imunização passiva, devem ser aplicadas, mesmo para aqueles previamente vacinados.

Vacinas contra varicela e vacina quádrupla viral / Varicella vaccines and measles, mumps, rubella, and varicella vaccine

OBJETIVOS: Apresentar uma revisão atualizada sobre os estudos de eficácia, eventos adversos e esquema vacinal da vacina contra varicela e a nova apresentação combinada com a vacina contra sarampo, caxumba e rubéola. FONTES DOS DADOS: Revisão bibliográfica utilizando a base de dados MEDLINE e LILACS no período de 1999 a 2006. SíNTESE DOS DADOS: A vacina contra varicela tem uma eficácia entre 70 a 90 por cento contra a infecção e 95 a 98 por cento de proteção contra as formas graves. É uma vacina bem tolerada e pouco reatogênica. Após o seu licenciamento, foram comprovados apenas três casos de transmissão do vírus vacinal de pessoas previamente saudáveis para contatos domiciliares, que desenvolveram doença leve. Apesar das evidências de que a proteção conferida pela vacina pode diminuir com o passar dos anos, ainda não é possível afirmar que seja necessário, no momento, a aplicação de uma segunda dose, tendo em vista a exposição ao vírus selvagem. Após a vacinação universal, as chances de estímulo natural deverão diminuir, e muito provavelmente será necessário a aplicação de doses de reforço. Recentemente foi licenciada a vacina quádrupla viral, um produto combinado com a vacina contra sarampo, caxumba, rubéola e varicela com elevadas taxas de soroconversão. CONCLUSÃO:A vacina contra varicela é recomendada pela Sociedade Brasileira de Pediatria (SBP) para as crianças a partir de 1 ano de idade. Esperamos que, em breve, a vacina quádrupla viral esteja disponível no Brasil, pois o uso de vacinas combinadas possibilita uma maior cobertura vacinal.

Immunogenetics and infectious diseases: special reference to the mayor histocompatibility complex

Many studies have tried to identify genetic markers for infectious diseases, some of them have focused on human leukocyte antigens (HLA). The products of HLA genes interact with surface-specific receptors of T lymphocytes, resulting in activation of the host's immune response. Association of bacterial, viral, parasitic and fungal infections with the host's HLA has been widely investigated. The type and strength of this association differs among distinct populations, as well as among racial and/or ethnic groups. The new molecular methods for the identification of the HLA alleles, and the resulting new nomenclature, have contributed to a better understanding of this system. Unfortunately, this information has not been adequately transmitted to clinicians, which hampers the understanding of the association between the HLA system and diseases. We revised relevant studies on the association of HLA genes with infectious diseases, demonstrating their importance in the pathogenic mechanisms, through increased susceptibility or protection against infections and their complications.

Recombinant viruses as vaccines against viral diseases

Vaccine approaches to infectious diseases are widely applied and appreciated. Amongst them, vectors based on recombinant viruses have shown great promise and play an important role in the development of new vaccines. Many viruses have been investigated for their ability to express proteins from foreign pathogens and induce specific immunological responses against these antigens in vivo. Generally, gene-based vaccines can stimulate potent humoral and cellular immune responses and viral vectors might be an effective strategy for both the delivery of antigen-encoding genes and the facilitation and enhancement of antigen presentation. In order to be utilized as a vaccine carrier, the ideal viral vector should be safe and enable efficient presentation of required pathogen-specific antigens to the immune system. It should also exhibit low intrinsic immunogenicity to allow for its re-administration in order to boost relevant specific immune responses. Furthermore, the vector system must meet criteria that enable its production on a large-scale basis. Several viral vaccine vectors have thus emerged to date, all of them having relative advantages and limits depending on the proposed application, and thus far none of them have proven to be ideal vaccine carriers. In this review we describe the potential, as well as some of the foreseeable obstacles associated with viral vaccine vectors and their use in preventive medicine.