Immunogenic Properties of Reverse Transcriptase of HIV Type 1 Assessed by DNA and Protein Immunization of Rabbits

Abstract

Genetic immunization may be one way to prime individuals for a subsequent broad anti-HIV-1 immune response. Reverse transcriptase of HIV-1 (RT) presents a selective target for attempts to arrest replication of HIV-1. Rabbits immunized with a plasmid carrying the gene for reverse transcriptase HIV-1 (RT DNA) developed potent antibody and cellular responses to the gene product. The immunogenic properties of RT DNA and recombinant reverse transcriptase were compared in rabbits. The specific immune responses were similar to those reported previously for HIV-1 infected humans. The array of B and T cell epitopes recognized in RT DNA-immunized rabbits was broader than in rabbits immunized with the recombinant RT. We localized seven novel B and T cell epitopes and concordance between B cell and helper T cell epitopes was observed. B cell epitopes of RT induced proliferation of peripheral blood mononuclear cells and were active as helper T cell epitopes. T cell-proliferative responses to the epitopes of RT preceded or paralleled the production of antibodies of the same specificity. Subdomains of reverse transcriptase involved in the enzymatic activity of RT were highly immunogenic. Anti-RT IgG partially inhibited reverse transcription in vitro.

Antibody responses against B‐cell epitopes of the hypervariable region 1 of hepatitis C virus in self‐limiting and chronic human hepatitis C followed‐up using consensus peptides

“…This is just one of the examples of T-cell/B-cell reciprocity in which helper T-cell epitopes determine antibody speci®city [for others see, for example, Walker et al, 1993;Ta È htinen et al, 1997;Isaguliants et al, 2000]. Cellular non-responsiveness to a T-helper cell epitope was associated with inability to form antibodies of the same speci®city (humoral non-responsiveness/tolerance) [Walker et al, 1993].…”

DNA-Encoding Enzymatically Active HIV-1 Reverse Transcriptase, but Not the Inactive Mutant, Confers Resistance to Experimental HIV-1 Challenge

“…Since we detected the formation of anti-double-stranded DNA antibodies in rabbits immunized with RT and DNA encoding RT we suspect that such a nucleic acid-protein complex occurred and was immunogenic in the immunized animals [23]. But the mutant enzyme will most likely also bind the primer, though perhaps not in such a way as to induce the same immune reaction as the active enzyme.…”

“…1a, b) and synthesized as described [13]. The half-time of dissociation of RT peptides in complex with HLA-A2 was predicted using a search engine at the web site: http:/ /bimas.dcrt.nih.gov/molbio/hla_bind/index.html.…”

“…ELISA was performed on 96-well plates (MaxiSorb, Nunc, Denmark) coated with RT or RT-derived peptides [13]. Recombinant RT was coated at a concentration of 0.2 Ìg/ml in carbonate-bicarbonate buffer, pH 9.4, for 16 h at 4° and peptides at 10 Ìg/ml for 16 h at 20° and then for 3 days at 4°.…”

Regulation of Transactivation Function of the Aryl Hydrocarbon Receptor by the Epstein-Barr Virus-encoded EBNA-3 Protein

“…Blood was collected 12 days after the second boost. Serum reactivity and specificity was tested by indirect ELISA on 96-well plates (MaxiSorp, Nunc, Denmark) coated with XAP2 peptide or unrelated antigens using a protocol described previously (26).…”