PubMed Health⌕ Search

Biomedical subjects

A Orrego

Publications and source records attributed to A Orrego.

6 recordsLinked to original sources
PubMed1984

Antigenic variation during persistent infection by equine infectious anemia virus, a retrovirus.

The recurrent nature of equine infectious anemia has been attributed to relatively rapid antigenic variations in equine infectious anemia virus (EIAV) during persistent infection under selective immune pressures. This model was tested by serological and biochemical analysis of virus isolates recovered from separate febrile episodes in two experimentally infected ponies. Neutralization assays employing immune sera from the experimentally infected ponies demonstrated that distinct antigenic strains of virus predominate during sequential febrile episodes in a single pony. Analysis of the test strains of EIAV by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed varying electrophoretic mobilities for the respective virion glycoproteins gp90 and gp45. Furthermore, peptide mapping comparisons demonstrated structural variations between the gp90 components of the various strains. In contrast, the respective internal proteins of the virus strains displayed identical electrophoretic mobilities in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and, in general, produced identical tryptic peptide maps. The observed differences in glycoprotein electrophoretic mobility and peptide maps were highly reproducible and did not vary with repeated passage of the virus strains in cell culture. Thus, these results demonstrate the occurrence of glycoprotein-specific structural variations during persistent infection by EIAV and support the concept of antigenic variation in this retrovirus. This capacity to alter envelope glycoprotein structure, previously reported for visna virus, may represent an important mechanism of retrovirus persistence in the presence of immune responses by the animal host.

Animals↗
PubMed1982

Virulence and in vitro growth of a cell-adapted strain of equine infectious anemia virus after serial passage in ponies.

Five serial passages of a cell-adapted strain of equine infectious anemia (EIA) virus were conducted in Shetland ponies. The 13 recipient ponies became agar-gel immunodiffusion test-positive by 25 days after they were inoculated. The virulence of the cell-adapted strain of EIA virus markedly increased through 3 serial passages, although individual variation within passages was high. The 1st serial-passage recipient remained afebrile through 200 days, whereas a febrile episode occurred about every 185, 44, 35, and 33 days in the 2nd, 3rd, 4th, and 5th serial-passage recipients, respectively. Severe clinical signs of EIA were noted in the ponies at each serial passage, but the mean virulence rating of each passage, graded on frequency of febrile episodes and number of clinical signs evident within 200 days after ponies were inoculated, increased from 0 through 4, 21, 24, and 29 for the 1st through 5th serial passages, respectively. Isolates of EIA virus, made in fetal equine kidney cells, were obtained from plasma of 75% of the samples of blood collected during febrile episodes and from 45% of the samples collected during afebrile periods, indicating that the cell culture growth capacity of this strain of EIA virus may be relatively stable through 5 serial passages in Shetland ponies.

Animals↗
PubMedDate not supplied

Bronchogenic gastric cyst. A case report.

A case of congenital bronchogenic cyst in the gastric mucosa is presented. The cyst was lined by pseudostratified epithelium and covered with ciliated cells. Congenital bronchogenic cysts should be differentiated from acquired gastric cysts lined with ciliated metaplastic cells that evolve as a result of environmental factors.

Adult↗