Immune response to respiratory syncytial virus in young Brazilian children

We have evaluated the cellular and humoral immune response to primary respiratory syncytial virus (RSV) infection in young infants. Serum specimens from 65 patients <=12 months of age (39 males and 26 females, 28 cases <3 months and 37 cases > or = 3 months; median 3 ± 3.9 months) were tested for anti-RSV IgG and IgG subclass antibodies by EIA. Flow cytometry was used to characterize cell surface markers expressed on peripheral blood mononuclear cells (PBMC) from 29 RSV-infected children. There was a low rate of seroconversion in children <3 months of age, whose acute-phase PBMC were mostly T lymphocytes (63.0 ± 9.0 percent). In contrast, a higher rate of seroconversion was observed in children >3 months of age, with predominance of B lymphocytes (71.0 ± 17.7 percent). Stimulation of PBMC with RSV (2 x 10(5) TCID50) for 48 h did not induce a detectable increase in intracellular cytokines and only a few showed a detectable increase in RSV-specific secreted cytokines. These data suggest that age is an important factor affecting the infants' ability to develop an immune response to RSV

Detection of rotavirus in sewage and creek water: efficiency of the concentration method

Simian rotavirus SA-11, experimentally seede, was recovered from raw domestic sewage by a two-step concentration procedure, using filtration through a positively charged microporous filter (Zeta Plus 60 S) followed by ultracentrifugation, effecting an 8000-fold concentration. By this method, a mean recovery of 81 per centñ7.5 of the SA-11 virus was achieved.

Serotypes and electropherotypes of human rotavirus detected in the city of São Luís (MA), Brazil

A total of 22 (65) of 34 representative rotavirus-positive specimens from infants with acute gastroenteritis were electropherotyped (RNA genome segments) and serotyped using an enzyme immunoassay with monoclonal antibodies (ELISA with MAbs). Serotype 3 was predominant during the 10-month study period (41), followed by serotype 1 (27) and serotype 4 (9). Serotype 2 was not found. Rotavirus strains were grouped into 3 major electropherotypes designated V, W and Z, each corresponding to a single serotype, i.e., serotypes 1, 3 and 4, respectively. Three strains that could not be typed by the serologic technique showed the W electrophoretic profile. The relative migration of the gene segments 7-9 was the main feature distinguishing the predominant serotype 3 from the other serotypes. The migration of segments 2 and 5 was also important for differentiating serotype 4 strains. The present study strengthens the view that electropherotyping, when used in conjunction with serotyping, can help characterize atypical and unusual strains, as well as rotaviruses that cannot be typed by the serologic technique.

Sindrome "mononucleose simile" na infancia. Incidencia da infeccao por citomegalovirus diagnosticada atraves de deteccao imunoenzimatica de anticorpos IgM. / Mononucleosis-like syndrome in childhood. Incidence of cytomegalovirus infection diagnosed by immunoenzymatic detection o IgM antibodies

Testando anticorpos IgM anti-citomegalovirus, pela tecnica imunoenzimatica ELISA, em 82 criancas com doenca "mononucleose simile" (reacao de Paul-Bunnell-Davidsohn negativa), os Autores diagnosticaram 5 casos (6%) de infeccao aguda por este agente. A presenca de linfonodomegalia cervical e exsudato de amigdalas em alguns destes pacientes sugere que a apresentacao clinica da citomegalomononucleose na infancia poderia, por vezes, ser distinta da forma classica do adulto