Reação de hemaglutinação passiva para o imunodiagnóstico da neurocisticercose humana: I. Padronização e avaliação do teste de hemaglutinação passiva para a detecção de anticorpos anti-Cysticercus cellulosae

Foi padronizada e avaliada a reação de hemaglutinação passiva (RHA) para pesquisa de anticorpos específicos, anti-Cysticercus cellulosae, no líquido cefalorraquiano (LCR). Foram utilizadas hemácias humanas O Rh-formolizadas e sensibilizadas com extrato antigênico salino total de cisticercos, ainda pouco estudado. De 115 amostras estudadas de LCR de pacientes com neurocisticercose, 94 foram reagentes, resultando em 81,7% de sensibilidade, com intervalo de confiança de 95% de probabilidade (IC95%) abrangendo de 74,5% e 88,9%. Também foram ensaiadas 89 amostras de LCR de indivíduos do grupo controle, sendo tão reagentes em 94,4%, com IC95%, de 89,6% a 99,2%. Os valores preditivos positivo e negativo obtidos para a RHA foram, respectivamente, de 1,4% e 99,9%, considerando a prevalência média de neurocisticercose na América Latina de 0,1%. Os resultados indicam que a RHA como um método simples, altamente reprodutível e moderadamente sensível para a detecção de anticorpos específicos no LCR, porém apropriados para a triagem de infectados.A passive haemagglutination test (PHA) for human neurocysticercosis was standardized and evaluated for the detection of specific antibodies to Cysticercus cellulosae in cerebrospinal fluid (CSF). For the assay, formaldehyde-treated group O Rh-human red cells coated with the cysticerci crude total saline extract (TS) antigen were employed. A total of 115 CSF samples from patients with neurocysticercosis was analysed, of these 94 presented reactivity, corresponding to 81.7% sensitivity, in which confidence limit of 95% probability (CL95%) ranged from 74.5% to 88.9%. Eighty-nine CSF samples derived from individuals of control group presented as nonreactive in 94.4% (CL95% from 89.6% to 99.2%). The positive and negative predictive values were 1.4% and 99.9%, respectively, considering the mean rate of that this assay provide a rapid, highly reproducible, and moderately sensitive mean of detecting specific antibodies in CSF samples

Reação de hemaglutinação passiva para o imunodiagnóstico da neurocisticercose humana: II - Comparação de duas metodologias para o preparo de reagente para a reação de hemaglutinação passiva na detecção de anticorpos anti-Cysticercus cellulosae no líquido cefalorraquiano

A comparison of two different standardized reagent procedures for the passive haemagglutination test (PHA) in the detection of specific antibody to Cysticercus cellulosae in cerebrospinal fluid (CSF) was carried out. The formaldehyde-treated group O Rh-human red blood cells (HuRBC) and glutaraldehyde-treated sheep red blood cells (SRBC) were the supplies for the reagents preparation and, in the tests, they were designated as PHA-1 and PHA-2, respectively. For both reagents the cells were coated with the cysticerci total saline extract (TS) antigen. PHA-1 and PHA-2 were assessed in a total of 204 CSF from patients with neurocysticercosis, from non-related infections and from healthy individuals. The positivity and specificity indices obtained were respectively 81.7% and 94.4% for PHA-1 and for PHA-2, 88.7% and 96.6%. Since no significant differences were observed between the results provided by two reagents, at level of significance of 0.05, either processes of cell sensitization can alternatively be used according to the own laboratory convenience.São descritas duas metodologias para o preparo de reagente para a reação de hemaglutinação passiva (RHA) destinada à pesquisa de anticorpos anti-Cysticercus cellulosae no líquido cefalorraquiano (LCR). Foram utilizadas hemácias humanas O Rh-formolizadas (HA-1) e hemácias de carneiro tratadas com glutaraldeído (HA-2), sensibilizadas com extrato antigênico salino total (ST) de cisticercos. Cento e quinze amostras de LCR de pacientes com neurocisticercose foram ensaiadas pelos testes HA-1 e HA-2, resultando em positividade de 81,7% e 88,7%, respectivamente. A especificidade obtida foi de 94,4% para HA-1 e 96,6% para HA-2. Não foi observada diferença significativa quanto à capacidade diagnostica dos reagentes na RHA em neurocisticercose (p < 0.05)

Effect of L-glutamine and L-alanyl-L-glutamine supplementation on the response to delayed-type hypersensitivity test (DTH) in rats submitted to intense training

O treinamento intenso e o exercício exaustivo podem ocasionar imunossupressão em atletas por meio da diminuição da concentração plasmática de glutamina. O presente estudo verificou inicialmente o efeito da suplementação com L-glutamina e L-alanilL-glutamina sobre a resposta ao teste de hipersensibilidade do tipo tardio (HTT) em ratos submetidos ao treinamento intenso em natação durante seis semanas. Posteriormente, foi avaliado o efeito dessas intervenções nutricionais sobre a contagem total e porcentual de leucócitos e concentração sérica de anticorpos IgG anti-albumina de soro bovino, em animais submetidos ao teste de exaustão e recuperados durante o período de 3 horas. Não houve efeito do treinamento e da suplementação sobre a resposta ao teste de HTT. Animais suplementados apresentaram maior concentração de glutamina no plasma (PIntense training and exhaustive exercise may cause immunesupression in athletes by reducing plasma glutamine concentration. Initially, this study verified the effect of L-glutamine and L-alanyl-L-glutamine supplementation on the response to delayed-type hypersensitivity test (DTH) in rats submitted to intense swimming training for six weeks. Later on, we assessed the effect of these nutritional interventions on total and differential white blood cell counts and on concentration of anti-bovine serum albumin IgG antibodies, in animals submitted to exhaustion test and a three-hour recovery period. There was no effect of training and supplementation on the response to DTH. Supplemented animals presented greatest plasma glutamine concentration (

Positive Selection Results in Frequent Reversible Amino Acid Replacements in the G Protein Gene of Human Respiratory Syncytial Virus

Human respiratory syncytial virus (HRSV) is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly temporal pattern of genetic variation, with a replacement of dominant genotypes occurring during consecutive years. In the present study we utilized phylogenetic methods to detect and map sites subject to adaptive evolution in the G protein of HRSVA and HRSVB. A total of 29 and 23 amino acid sites were found to be putatively positively selected in HRSVA and HRSVB, respectively. Several of these sites defined genotypes and lineages within genotypes in both groups, and correlated well with epitopes previously described in group A. Remarkably, 18 of these positively selected tended to revert in time to a previous codon state, producing a “flip-flop” phylogenetic pattern. Such frequent evolutionary reversals in HRSV are indicative of a combination of frequent positive selection, reflecting the changing immune status of the human population, and a limited repertoire of functionally viable amino acids at specific amino acid sites

Stability of anti-HIV antibodies in serum samples stored for two to eighteen years periods

Introduction: The antibodies have an important role in the serodiagnosis, constituting the most widely used biomarkers to detect and confirm various diseases. Objective: To investigate the reproducibility of anti-human immunodeficiency virus (HIV) antibodies reactivity, to assess the stability of the sera samples stored at -20&#186;C for two to eighteen years. Method: Sera were collected in the period 1988-2004 for routine anti-HIV antibodies diagnostic testing. The remaining samples stored at -20&#186;C, were analyzed in this study. Serum sample stability was assessed by enzyme-linked immunosorbent assay/enzyme immunoassay (ELISA/EIA), indirect immunofluorescence assay (IFA), and Western blot (WB) for detecting anti-HIV antibodies. The previously found results (1988-2004) and those obtained in 2006 were subjected to Kappa index analysis. Result: In the period 1988-to 2004, the degree of concordance of the ELISA/EIA, IFA and WB results were considered, good (k = 0.80), regular (k = 0.35), and good (k = 0.63), respectively. Conclusion: Regarding HIV serologic test, the serum samples were stable for 18 years in ELISA/EIA and for 4 years in IFA technique, however, for the WB methodology it was not possible to determine the time of stability of the anti-HIV antibodies