Lower respiratory tract infection caused by respiratory syncytial virus in infants: the role played by specific antibodies

INTRODUCTION: Respiratory syncytial virus (RSV) is a major etiological agent of lower respiratory tract infection in infants. Genotypes of this virus and the role of the infants' serum antibodies have yet to be fully clarified. This knowledge is important for the development of effective therapeutic and prophylactic measures. OBJECTIVES: To evaluate the types and genotypes of RSV causing respiratory tract infection in infants, to analyze the association of subtype-specific serum antibodies with the occurrence of infection and to evaluate the presence of subtype-specific antibodies in the infants' mothers and their association with the profile of the childrens' serum antibodies. METHODS: This was a prospective study on infants hospitalized with respiratory infection. Nasopharyngeal secretions were collected for viral investigation using indirect immunofluorescence and viral culture and blood was collected to test for antibodies using the Luminex Multiplex system. RESULTS: 192 infants were evaluated, with 60.9 percent having RSV (73.5 percent- A and 20.5 percent B). Six genotypes of the virus were identified: A5, A2, B3, B5, A7 and B4. The seroprevalence of the subtype-specific serum antibodies was high. The presence and levels of subtype-specific antibodies were similar, irrespective of the presence of infection or the viral type or genotype. The mothers' antibody profiles were similar to their infants'. CONCLUSIONS: Although the prevalence of subtype-specific antibodies was elevated, these antibodies did not provide protection independently of virus type/genotype. The similarity in the profiles of subtype-specific antibodies presented by the mothers and their children was consistent with transplacental passage.

INTRODUÇÃO: O vírus sincicial respiratório é um dos principais agentes etiológicos das infecções do aparelho respiratório inferior em lactentes. Os genótipos deste vírus e o papel dos anticorpos séricos ainda não estão esclarecidos. Este conhecimento é importante para o desenvolvimento de medidas terapêuticas e profiláticas. OBJETIVOS: Avaliar: os tipos e genótipos do vírus sincicial que causam infecção respiratória em lactentes e a associação dos anticorpos séricos subtipo-específicos com a ocorrência de infecção; a presença de anticorpos subtipo-específicos nas mães e sua associação com o perfil de anticorpos da criança. MÉTODOS: Estudo prospectivo incluindo lactentes hospitalizados com infecção respiratória. Foi coletada secreção de nasofaringe para investigação viral usando imunofluorescência indireta e cultivo viral. Foi coletado sangue para pesquisa de anticorpos usando o sistema Luminex Multiplex. RESULTADOS: Avaliados 192 lactentes: 60,9 por cento com vírus sincicial (73,5 por cento - A e 20,5 por cento - B). Seis genótipos de vírus sincicial respiratório foram identificados: A5,A2,B3,B5,A7 e B4. A soroprevalência dos anticorpos subtipos-específicos foi alta. A presença e o nível de anticorpos subtipos-específicos foram semelhantes, independentemente da presença de infecção, tipo e genótipo do vírus. As mães e as crianças apresentaram perfis semelhantes de anticorpos. CONCLUSÕES: A prevalência dos anticorpos subtipos-específicos foi elevada mas estes anticorpos não conferiram proteção, independentemente do tipo/genótipo do vírus. A semelhança dos perfis de anticorpos das mães e das crianças foi compatível com transmissão transplacentária.

Development of a Web-based Program for the Identification of Human Leukocyte Antigen Antibody Specificities / 대한진단검사의학회지

BACKGROUND: Panel reactive antibody (PRA) test is used to determine whether a patient awaiting transplantation is previously sensitized. Tail analysis algorithm is widely used to identify antibody specificities, but it is very difficult to perform manually. METHODS: To develop a web-based program, PHP (5.1.2), Apache (2.0.55), and MySQL (5.0.22) were used. Tail analysis algorithm was applied to identify specificities, which analyzed statistically 2 x 2 tables representing reactivities to broad antigens, splits and cross reactive groups (CREG). Exploiting two CREG classifications of Rodey (R) and Takemoto (T), antibody specificities were identified by 3 methods (ABC, R-ABC, T-ABC) simultaneously. Performance of the system was evaluated using 159 samples that showed > or =6 PRA% by a lymphocytotoxicity assay. RESULTS: A web-based system that can identify HLA antibody specificities was implemented on www.koreanhla.com. Among 159 samples tested, antibody specificities were identified in 151 (95.0 %), but not in 8 samples with PRA >97%. Among the 151 samples, 110 showed broad or split specificities and 41 CREG specificities. CONCLUSIONS: We developed a web-based computer program for the identification of HLA antibody specificities. Accessible to everyone on the internet, this program should be of help in sharing PRA results among laboratories.

Human immunodeficiency virus type 1 neutralization by plasma from B or F genotype infected individuals

Anti-human immunodeficiency virus type 1 (HIV-1) "binding antibodies" (antibodies capable of binding to synthetic peptides or proteins) occur throughout HIV-1 infection, are high-titered and highly cross-reactive, as confirmed in this study by analyzing plasma from B and F genotype HIV-1 infected individuals. Plasma from individuals infected with clade F HIV-1 displayed the most frequent cross-reactivity, in high titers, while Bbr plasma showed much higher specificity. Similarly, neutralization of a reference HIV-1 isolate (HIV-1 MN) was more frequently observed by plasma from F than B genotype infected individuals. No significant difference was seen in neutralization susceptibility of primary B, Bbr or F clade HIV-1 by plasma from individuals infected with the classical B (GPGR) or F HIV-1, but Bbr (GWGR) plasma were less likely to neutralize the F genotype primary HIV-1 isolates. The data indicate that both B and F genotype derived vaccines would be equally effective against B and F HIV-1 infection, with a slightly more probable effectiveness for F than B genotype. Although the Bbr variant appears to induce a much more specific humoral immune response, the susceptibility in neutralizing the Brazilian HIV-1 B genotype Bbr variant is similar to that observed with the classical B genotype HIV-1.

Rapid characterization of S. mansoni expression library clones of potential interest

Uma biblioteca de expressao de cDNA de verme adulto de S. mansoni foi selecionada utilizando-se soros de macacos babuinos em fase inicial da infeccao. Os clones que reagiram positivamente com os soros de infeccao recente foram examinados quanto a reatividade contra soros normais e soros de infeccao heterologa. Com a finalidade de se conseguir melhor discriminacao entre reatividade positiva com o anticorpo especifico e aquela devido aos anticorpos anti-E. coli residuais, um clone de cDNA nao relacionado ao S. mansoni foi plaqueado em mistura com o clone positivo. O plano de fundo negativo proporcionado pelo clone nao relacionado forneceu o contraste necessario para discriminar a reacao positiva especifica...