HIV-1 subtypes among blood donors from Rio de Janeiro, Brazil.

The prevalence of HIV infection in Brazil is one of the highest in the world. In addition, transfusion-transmitted HIV accounts for 2.3% of all AIDS cases in Brazil. The objective of this study was to evaluate genetic diversity and distribution of HIV-1 strains circulating in the blood-donor population. We characterized 43 seropositive blood units collected from volunteer blood donors residing throughout Rio de Janeiro, Brazil. Viral RNA was extracted from plasma, reverse transcribed, and amplified by nested polymerase chain reaction (PCR) using HIV group M degenerate primers. Genetic heterogeneity was evaluated by direct automated cycle sequencing of the following gene fragments: gag p24 (399 bp), env C2V3 (345 bp), and env gp41 (369 bp). Phylogenetic analysis reflected the complexity of the Brazilian HIV epidemic: the majority of specimens, 33 of 43 (76.7%) were subtype B, and 6 of 43 (14%) were subtype F. The remaining 4 samples (9.3%) involved potential mosaic viruses of subtypes B and F or B and D. This survey is the first to document HIV-1 genetic variation in the Brazilian blood-donor population.

PIP: Brazil has the highest prevalence of HIV infection in Latin America and one of the highest such prevalences in the world. By 1996, 110,000 AIDS cases had been cumulatively reported by the Brazil National AIDS Program. HIV-1 subtypes B and F have previously been described in Brazil, accounting for 85% and 15% of infections, respectively. Findings are presented from a study conducted to evaluate the genetic diversity and distribution of HIV-1 strains circulating in the blood donor population. The authors characterized 43 HIV-seropositive blood units collected from volunteer blood donors living throughout Rio de Janeiro. Viral RNA was extracted from plasma, reverse transcribed, and amplified by nested polymerase chain reaction using HIV group M degenerate primers. Genetic heterogeneity was assessed through the direct automated cycle sequencing of gene fragments gag p24 (399 bp), env C2V3 (345 bp), and env gp41 (369 bp). 33 of the 43 (76.7%) specimens were of subtype B and 6 (14%) of subtype F, while the remaining 4 (9.3%) involved potential mosaic viruses of subtypes B and F or B and D.

[Anti-HBs antibodies from rabbits and their use as reagents for serological tests in the diagnosis of hepatitis B]. / Anticorpos anti-HBs obtidos em coelhos e sua utilizacão como reagentes para testes sorológicos no diagnóstico da hepatite B.

By the method of affinity chromatography a partially purified antigen was obtained after passing the plasma of an asymptomatic carrier of HBsAg through a column of Sepharose 4B linked to angi-HBs. This antigen was inoculated in rabbits using a schedule of 1,0 mg in the first dose and 4 other doses of 0,5 mg with intervals of approximately 15 days. Observing that blood samples collected after the 5th inoculation showed no change in antibody levels, the animals were bled on the 62th day and these immune sera were standardized with the following tests for the detection of HBsAg: Reverse passive hemagglutination (R-PHA) - using specific gamma globulin that was obtained from rabbit sera by affinity chromatography and reaching an optimal concentration of 10 micrograms/ml to sensitise SRBC at 5% fixed in glutaraldehyde. Counter immuno electrophoresis (CIEP) - using the rabbit immune sera diluted to 1/20 as a reagent for the detection of HBsAg. The immune sera was also used to conjugate new Sepharose 4B for affinity chromatography and was found having a linking capacity of approximately 0,5 to 1,0 mg of HBsAg per ml of Sepharose after complete saturation.

Anticorpos anti-HBs obtidos em coelhos e sua utilizacao como reagentes para testes sorologicos no diagnostico da hepatite B. / Anti-HBs antibodies obtained in rabbits and its use as reagents for serological tests in the diagnosis of hepatitis B

Pela tecnica de cromatografia de afinidade utilizando-se a resina de Sepharose 4B ligada ao anti-HBs, obteve-se na passagem de plasma de portador assintomatico de antigeno HBs, um antigeno parcialmente purificado. Este antigeno foi utilizado para a inoculacao em coelhos, num esquema de cinco doses, sendo a primeira dose de 1 mg e as quatro subsequentes de 0,5 mg, com intervalos aproximadamente de quinze dias.Obsevando-se que os titulos nao mais variaram apos a quinta inoculacao os animais foram sangrados no 62o dia e os anticorpos anti-HBs obtidos foram padronizados atraves dos seguintes metodos para deteccao de antigeno HBs: a) Hemaglutinacao passiva reversa (HAPR) - utilizando-se a gamaglobulina especifica obtida de soro imune dos coelhos atraves de cromatografia de afinidade, alcancando uma concentracao otima de apenas 10 micros/ml para a sensibilizacao de hemacias de carneiro a 5%, fixadas com glutaraldeido. b) Contraimunoeletroforese (CIEF) - utilizando-se o soro imune diluido ate 1/20 como reagente para a deteccao do antigeno HBs. O soro imune anti-HBs foi tambem utilizado para a conjuncao com uma nova resina de Sepharose 4B tendo uma captacao aproximada de 0,5 a 1,0 mg de antigeno HBs por ml de resina apos completa saturacao